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Патент USA US3055988

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Sept 25, 1962
s. sHARlN ETAL
3,055,978
CONTROL CIRCUIT
Filed Dec. l5, 1956
5 Sheets-Sheet l
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S. SHARIN ETAL
CONTROL -CIRCUIT
3,055,978
Filed Dec. l5, 1956
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s.sHAR1N ETAL
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CONTROL CIRCUIT
Filed Deo. 15, 1956
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3,055,973
CONTROL CIRCUIT
Filed Dec. 13, 1956
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SAMUEL SHAHIN
THDMAS R. SHERIDAN
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HAJIME J. KIsI-n
Sept. 25, 1962
s. sHARlN ETAL
3,055,978
CONTROL CIRCUIT
Filed Dec. 13, 1956
5 Sheets-Sheet 5
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United States Patent Chfice
1
3,055,978
CONTROL CIRCUIT
Samuel Sharin and Thomas R. Sheridan, Brooklyn, and
Anthony Liguori and Hajime James Kishi, Huntington
Station, NX., assignors to Radio Corporation of
America, a corporation of Delaware
Filed Dec. 13, 1955, Ser. No. 628,088
2l Claims. (Cl. 17S---23)
3,055,978
Patented Sept. 25, 1962
2
system, whereby a code character received distorted is
automatically retransmitted by the transmitting terminal
station until it is correctly received at the receiving
terminal station.
Circuits for performing the code converting and error
detecting functions outlined above are presently available
in the art.
known.
Both electronic and mechanical circuits are
The mechanical circuits, including the use of
priming windings, relays and so on, are not completely
The invention relates to control circuits. More par
satisfactory because they create difficult mechanical main
ticularly, the invention relates to an electronic code con
tenance problems. Such circuits tend to be complicated
verting and error detecting control circuit which can be
in construction and operation. The electronic circuits
adapted for use in a telegraph communication system.
presently
available require a number of vacuum tubes.
Telegraph printing devices are designed for the most
part to receive `and/or transmit the code characters of a 15 While some of the problems encountered in using the
mechanical circuits are eliminated by the use of the elec
standard fixed-length telegraph code, for example, the
tronic
circuits, the number of vacuum tubes needed in
five-unit fixed-length telegraph code. Each code char
the electronic circuits now available presents the problem
acter of the five-unit »telegraph code includes an arrange
of heat dissipation and makes the circuits expensive to
ment of marking and spacing elements. A code char
acter may include five marking elements, five spacing ele 20 construct and maintain in terms of components and power
consumption. Because of the number of vacuum tubes
ments or a combination of marking and spacing elements
needed, the electronic circuits tend to be bulky and awk
arranged in a predetermined manner. Marking elements
ward to handle, thereby adding to the problems encoun
are generally defined as intervals of current flow, while
tered
in designing equipment including a code couver-ting
spacing elements are generally defined as intervals of no
and error detecting circuit of this type.
current iiow. The transmission of a telegraph message 25
it is an object of the invention to provide an improved
signal between remotely located telegraph terminal sta
electronic
circuit for converting code characters of a
tions using such a telegraph code, for example, by means
given telegraph code into the corresponding code charac
of a radio frequency transmission system, has not been
yters of a different telegraph code, including equipment for
entirely satisfactory. Marking elements included in a
detecting the reception by the circuit of a distorted code
30
code character may -be deleted by atmospheric conditions,
character
of the given telegraph code.
while spacing elements may be filled in by noise, and so
on.
As the ratio of marking elements to spacing elements
is not the same in each character of the five-unit tele
Another object of the invention is to provide a more
compact, simpler and improved code converting and
graph code, it is diii'icult to design equipment for detecting
error detecting circuit using magnetic cores to perform
ing the transmission thereof and, thereafter, placing the
necessary correcting equipment in operation.
converting and error detecting circuit using single mag
functions heretofore performed by other equipment.
an erroneous code character which has been distorted dur 35
The objects of the invention are accomplished by a code
Various telegraph codes known in the art as protected
telegraph codes have been developed to remove this diffi
netic cores and a number of magnetic core shift registers.
Each of the shift registers includes a number of magnetic
culty. The marking and spacing elements in the code 40 cores connected to form a chain or train of magnetic cores
in a manner known in the art. An incoming telegraph
characters of a protected telegraph code are arranged such
message signal including code characters of a given tele
that a received distorted code character can be readily
graph code is applied from suitable receiving equipment
detected. For example, the code characters of the seven
to
a distributing circuit. In describing the invention, it
unit, fixed-length protected telegraph code each include
a ratio of three marking elements to four spacing elements. 45 will be assumed that the incoming message signal includes
code characters of the seven-unit telegraph code and that
A distorted code character including more or less than
the circuit of the invention is required to convert the code
three marking elements can be detected by providing
characters of the seven-unit telegraph code into the corre:
equipment rfor counting the marking elements in each code
sponding code characters of the five-unit telegraph code.
character as it is received, the equipment being arranged
to place the necessary correcting equipment in operation 50 However, as will be discussed, the circuit may be designed
for use with other telegraph codes without departing from
upon the detection of a distorted character.
the spirit of the invention.
In the use of a protected telegraph code, code charac
The distributing circuit includes an arrangement of
ters are first produced using the standard telegraph code.
single magnetic cores and functions to distribute the signal
Equipment is provided ata telegraph transmitting terminal
station for converting the code characters into the corre 55 elements included in a received code character to a pair
spending code characters of the protected telegraph code
and for transmitting the converted code characters to a
telegraph receiving terminal station. Equipment is pro
of magnetic core shift registers which are designated as a
mark shift register and a space shift register, respectively.
Each code character of the seven-unit telegraph code
includes three marking elements and four spacing ele
vided at the receiving terminal station for converting the
code characters of the protected telegraph code into the 60 ments. The marking and spacing elements are arranged
in a predetermined order for each code character of the
corresponding code characters of the standard telegraph
seven-unit telegraph code. The distributing circuit func
code and for feeding the code characters of the standard
tions to establish an electrical condition in various ones of
telegraph code to an utilization circuit such as a telegraph
the magnetic cores in the mark shift register according to
printing device. Additional equipment is provided for
the order in which the marking elements appear in an
checking each code character of the protected telegraph
incoming code character of the seven-unit telegraph code.
code as it is received and for placing the necessary correct
The distributing circuit also functions to establish an elec
ing equipment in operation upon the detection of a dis
trical condition in various ones of the magnetic cores in
torted or erroneous character. The correcting equipment
the space shift register according to the order in which the
may function to cause the printing of a given code char
acter in place of the distorted code character received or 70 spacing elements appear in the incoming code character
of the seven-unit telegraph code. As a result of this ac
to cause the operation of an automatic repetition request
tion, the incoming code character is stored in the mark
3,055,978
3
`and space shift registers in a binary form when the mark
and space shift registers are considered as a single unit.
In addition to being applied to the magnetic core dis
tributing circuit, the incoming telegraph message signal
is simultaneously applied to an error detecting circuit.
The error detecting circuit includes a magnetic core
shift register designated as a mutilation shift register
and a single magnetic core. The error detecting circuit
functions to count the number of marking elements in
the incoming code character by the operation of the
mutilation shift register. Each code character of the
seven-unit telegraph code includes three marking ele
ments. If more than or less than three marking ele
ments are counted in a code character, a distorted code
character has been received and is detected.
IFollowing the establishment of an incoming code char
acter in the mark and Space shift registers in binary
form and the determination of the number of marking
elements in the code character by the operation of the
mutilation shift register, the binary information corre 20
A
driving unit 11. The driving unit 11 functions to apply
the signal elements included in each code character of
the message signal to a magnetic core distributing cir
cuit 1Z over lead 13 and to a magnetic core error detect
ing circuit 14 over lead 9.
The magnetic core dis
tributing circuit 12 includes a number of single magnetic
cores which are interconnected so as to perform func
tions which will be described in detail. The magnetic
core error detecting circuit 14 includes a mutilation mag
netic core shift register and a single magnetic core.
The operation of magnetic cores and of magnetic core
shift register, per se, is known in the art, and, therefore,
a detailed description thereof is unnecessary. A mag
netic core is a circuit element having a rectangular
hysteresis loop of low coercive force. Certain materials
such as molybdenum~permalloy and manganese-magne
sium ferrite exhibit a substantial rectangular hysteresis
loop. Input, output and shift windings are arranged on
sponding to the incoming code character is applied from
the mark and space shift registers to a code converter.
The code converter which may, for example, include a
diode matrix of a type known in the art, functions in
response to the binary information to convert the income 25
the core. A magnetic core is capable of being mag
netized to saturation in either one of two directions.
In one direction, a positive or active state is said to
arise in which the direction of retentivity is opposite to
that which would result from the application of a shift
current or sensing pulse to the shift winding of the core.
In the second direction, a negative or inactive state is said
to arise in which the direction of retentivity is the same
ing code character of the seven-unit telegraph code into
as that which would result from the application of a
the corresponding code character of the iive-unit tele
shift current pulse to the shift winding on the core. When
graph code. The converted code character is applied
applied to a magnetic core in the active state, a shift
to an output circuit which, in turn, functions to apply
the converted code character to an utilization circuit 30 current pulse will cause the inactive state to appear.
When applied to a magnetic core already in the inactive
connected thereto. If the mutilation shift register has
state, a shift current pulse will cause no change in state.
determined that the incoming code character is distorted,
A magnetic core in the active or positive state is said to
the single magnetic core included in the error detecting
contain a “one,” and a magnetic core in the negative or
circuit is operated to apply a control signal to the out
inactive state is said to contain a “zero” When a mag
put circuit. The output circuit yfunctions to apply the
control signal to the utilization circuit along with the
conversion of the distorted code character received. The
utilization circuit, for example, a telegraph printing de
netic core is shifted from an active state to an inactive
state, a voltage is induced in its output winding for ap
plication to an utilization circuit connected thereto. A
shift current pulse will have no substantial effect on a
vice, functions to process a code character received, in
the absence of a control signal received from the output 40 magnetic core in the inactive state, and substantially no
voltage will be induced in its output winding.
circuit, in the normal manner. When a code character
is received from the output circuit accompanied by a
control signal, equipment included in the utilization cir
cuit may be placed in operation to bring about the corn
pletion of certain prearranged procedures. The equip 45
ment may be included in an automatic repetition request
system which functions to cause a code character of
the seven-unit telegraph code originally received distorted
to be retransmitted by the telegraph transmitting termi
nal station until it is received correctly, as indicated
If a “one” is stored in a ñrst magnetic core in a chain
of magnetic cores included in a shift register such that
the core is in an active state, the application of a shift
current pulse to the shift winding on the core causes a
voltage to be induced in the output winding on the core.
The output winding on the ñrst magnetic core is con
nected to the input winding on a succeeding core in the
chain. The voltage induced in the output winding on
the first magnetic core is applied to the input winding on
the next magnetic core in the chain, causing a “one” to be
A
stored in the next magnetic core. Thus, the “one” is
code converting and error detecting circuit is disclosed
transferred from the first magnetic core to a second mag
by the invention which is more compact and simpler
netic core included in the shift register. Additional shift
than the code converting and error detecting circuits pre
55 current pulses can be selectively applied to the magnetic
viously available in the art.
cores in the chain of magnetic cores to cause the “one”
A more detailed description of the invention follows
to
advance core-by-core along the chain of magnetic cores
with reference to the accompanying drawing, in which:
included in the shift register. As a result of the actions
FIGURE l is a block diagram of a code converting
outlined above, a single magnetic core, as well as a mag
and error detecting circuit according to the invention;
FIGURES 2a, 2b and 2c together show a circuit dia 60 netic core shift register, can be adapted to per-form vari
by the operation of the multilation shift register.
gram of one embodiment of a code converting and error
ous functions.
In the code converting and error detecting circuit of
the invention, as shown in the block diagram given in
FIGURE l, the magnetic cores included in the distribut
block diagram of FIGURE l;
i
ing circuit 12 4function to distribute the signal elements
vFIGURE 3 is a timing diagram used in explaining the
of each seven-unit code character received to a mark shift
operation of the circuit diagram shown in FIGURE 2;
register 1‘5 over lead 16 and to a space shift register 17
and
over lead 18. Upon the reception of each marking ele
FIGURE 4 is a block diagram of an automatic tele
ment in a code character, a control pulse is applied
graph communication system in which the code convert
ing and error detecting circuit of the invention may find 70 from the distributing circuit 12 to the mark shift register
detecting circuit constructed according to the arrange
nient of the invention shown by way of example in the
application.
Referring to the block diagram shown in FIGURE l,
a telegraph message signal is applied from suitable re
15 over lead 16 such that a “one” is stored in a mag
netic core included therein. As a result »of this action,
a “one” is stored in certain of the magnetic cores included
in the mark shift register 1S according to the order in
The rnes
sage signal is applied from the input terminal 10 to a 75 which the marking elements appear in a code character
ceiving equipment to an input terminal 10.
5
3,055,978
received. Upon the reception of each spacing element in
the code character, a control pulse is applied from the
distributing circuit y12 to thc space shift register 17 over
lead 18 such that a “one” is stored in certain of the mag
netic cores included in the space shift register 17 accord
ing to the order in which the spacing elements appear
in the code character received. Upon the reception of a
complete and correct code character of the seven-unit tele
graph code, therefore, a “one” will be stored in three
of the magnetic cores included in the mark shift register
15 over lead 16 such that a “one” is stored in a mag
netic cores therein. A “one” will be stored in four of
the magnetic cores included in the space shift register
17, and a “zero” will >be stored in the remaining mag
netic cores therein. :In other words the code character
received is stored in one sense in the mark shift register
15 and in the opposite sense in the space shi-ft register
17. The code character is said to be stored in a binary
form in the registers 15, 17.
As a code character is received by the distributing cir
cuit 12 over lead 13, the signal elements included therein
values have been assigned to various positive and negative
terminals connected to suitable sources of potential and
arranged in the circuit diagram. The values, however,
are given only by way of example, and can be altered
to meet the requirements of a particular `application with
out departing from `the spirit of the invention.
The operation of the code converting and error detect
ing circuit according to the invention requires two input
trains of timing pulses. Referring to FIGURE 3, the
first train of timing pulses includes a series of pulses P3
through P21 shown by the larger arrows. The pulses
P3 through P21 occur at regular intervals, -for example,
at approximately 208 microsecond intervals. The second
train of timing pulses includes a series of pulses P3'
through P241’ shown by the smaller arrows. The pulses
Pf3’ through P20’ of the second train are interspersed
in time between the pulses P3 through P21 of the ñrst
train such that each of the pulses P3’ through P20’ of
the second train »occurs between succeeding pulses P3
through P21 of the ñrst train. The pulses P3’ through
P26’ are taken to be one-half cycle behind the pulses P3
through P21 as a reference. The 4second train of pulses
are applied to the error detecting circuit 14 over lead
9. The marking elements in the code character received
P3’ through P20’ is continuous throughout the circuit of
the invention, while the first train of pulses P3 through
P21 is gated to perform «the logic of the circuit. The
respective trains of timing pulses have been shown for
are counted by the operation of the mutilation register
included in the error detecting circuit 14. -If the correct
num-ber of marking elements are counted, namely, three,
no further circuit operations occur as a -result of the
simplicity of drawing and description as being supplied
operation of the error detectin-g circuit 14. The mark
by a timing wave generator 26. In actual practice, one
and space shift registers 15, 17 are operated to apply the
or both of the trains of timing pulses may be supplied as
binary information stored therein to a code converter
19 over leads 20l and 21, respectively. The code convert 30 a function of other equipment included in a telegraph
receiving terminal station of which the circuit of the in
er 19, which may, for example, include a diode matrix
vention is a part. One of the trains of pulses may be
acter of the tive-unit telegraph code. The converted code
character is applied from the code converter 19 to an
output, magnetic core shift register 22 over lead 23. The
shift register 22 `functions to apply the code character to
an utilization circuit via an output terminal 24.
If the mutilation shift register included, in the error
detecting circuit 14 detects a distorted code character,
supplied as a `function of a frequency correction unit
connected between the timing wave generator 26 and the
input circuit of the invention, the frequency correction
unit functioning to synchronize `the timing pulses sup
plied by the timing wave generator 26 with the incoming
telegraph message signal. An example of a timing wave
generator using magnetic cores that can be adapted for
40 use with the code converting and error detecting cir
cuit of the invention is given in copending United States
patent application Serial Number 616,275, tiled October
16, 1956 on behalf of H, J. Kishi, A. Liguori and T. R.
45
Sheridan for Timing Circuit, now Patent No. 3,012,228,
issued Dec. 5, 1961.
The embodiment of the invention shown in the circuit
diagram given in FIGURE 2 includes a first- magnetic
core shift register l15 designated as a mark shift register
and a second magnetic core shift register 17 designated
50 as a space shift register. The space shift register 17
includes a chain of fourteen magnetic cores 40 through
detecting circuit 14 to the utilization circuit connected
53 arranged in two rows of seven magnetic cores each.
thereto via output terminal 24. The utilization circuit
The type of magnetic core shift register shown is gen
preferably includes equipment responsive to the recep
tion of the control signal to first
erally referred to as a two core per bit shift register.
The even numbered magnetic cores constitute a line of
the utilization circuit in response to the conversion of the
storage cores, while the odd numbered magnetic cores
distorted code character and, thereafter, to effect a cor
constitute a line of temporary storage cores. Input, out
rection of the distorted code character, and so on.
put and shift windings are arranged on each of the mag
netic cores 45 through 53.
cuit of the invention in the manner outlined above is 60 respective windings on each of the magnetlc cores in
controlled by timing pulses supplied .by a timing wave
generator 26. The timing pulses prod-uced by the opera
tion of the generator 26 are applied to a driving unit 27.
The driving unit 27 functions to supply timing pulses
in the proper sequence and at the desired rates of fre
quency to the error detecting circuit 14 over lead 28, the
Assuming for the moment that a current flows through
the input winding 54 on the first magnetic core 40 in
the space shift register 17, the negative voltage induced
distributing circuit 12 over lead 29, the mark and space
in the input winding 54 causes the magnetic core 40 to
shift registers 1'5 and 17 over lead 30, the code converter
assume an active state having a “one” stored therein.
19 over lead 31 fand to the output shift register 22 over
lead 32. The various circuit components are operated in 70 If a shift current pulse is thereafter applied to the shift
winding 55, a voltage is induced in the output winding
the proper timed sequence in response to the timing pulses
to perform the functions described.
56. The voltage induced in the output winding 56 causes
current to be applied to the input winding 57 on the next
An embodiment of the invention is shown .by way of
magnetic core 41 in the chain over a connection 58 in
example only in the circuit diagram given in FIGURE 2.
To assist in an understanding of the invention, voltage 75 cluding an unidirectional impedance device 59, for ex
ample, a rectitier. Various other unidirectional imped
L.
3,055,978
8
81 through S7 in response to shift current pulses applied
ance devices are used elsewhere in the circuit. The
at first to the shift windings on the line of storage cores
devices are shown in FIGURE 2 and are identified in the
and, thereafter, to the shift windings on the line of tem
specification as rectiliers. It is to be understood that the
porary storage cores. The distributing circuit 12 includes
embodiment of the invention is not limited to the use
three single magnetic cores 88 through 9i) which are con
of the particular type of device shown but that other Cil nected together in a manner to be described. As pre
devices known in the art which are adapted to pass cur
viously mentioned, the distributing circuit 12 and error
rent therethrough in only one direction may be used
without departing from the spirit of the invention. The
rectifier 59 is poled in the proper direction to permit the
detecting circuit 14 are responsive to the signal elements
included in a received code character which are applied
thereto by a driving circuit 11. The driving circuit 11
passage of current from the output winding 56 to the
includes a gating triode vacuum tube 91, a blocking os
input winding 57. The magnetic core 4d assumes an
cillator triode vacuum tube 92 and a driving triode Vac
inactive state having a “Zero” stored therein. The sec
uum
tube 93.
ond magnetic core 41 operates in response to the voltage
The mark and space shift registers 15, 17 function to
induced in the input winding 57 to assume an active
store a received code character in binary form in re
state having a “one” stored therein. Thus, the “one” is 15 sponse to the operation of the magnetic cores 88 through
transferred or advanced from the first magnetic core 40
9i) in the distributing circuit 12. The binary information
to the second magnetic core 41.
is applied from the respective mark and space shift reg
When a shift current pulse is applied to the shift wind
isters 15, 17 to a code converter 19. The code converter
ing 60 on the magnetic core 41, a voltage is induced in
19 preferably includes a diode or rectifier matrix. Ex
the output winding 61. Current is applied from the out
amples of this type of code converter are known in the
put winding 61 to the input winding 62 on the third mag
art and need not be described in detail. One example of
netic core 42 in the chain over a connection 63 includ
a code converter using a rectifier matrix which can be
ing a rectifier 64. Magnetic core 41 assumes an inactive
readily adapted for use in the circuit of the invention is
state having a “zero” stored therein. The magnetic core
shown .and described in Patent Number 2,724,739, issued
42 is operated in response to the voltage induced in the 25 on November 22, 1955, to James S. Harris for Code Con
input winding 62 to assume an active state having a “one”
version System. The rectifier matrix functions in re
stored therein. The “one” is advanced from the second
sponse to the binary information applied thereto to con
magnetic core 41 to the third magnetic core 42. When
vert a received code character of a given telegraph code
the “one” is advanced out of the magnetic core 41, a
30 into the corresponding code character of a different tele
voltage is also induced in the input winding 57. The
rectifier 59 in the connection 58 is, however, poled in the
proper direction to prevent current from being applied
from the code converter 19 to an output shift register 22
to the output winding 56 on the magnetic core 40. As a
result, the “one” is not fed back from the second mag
netic core 41 to the first magnetic core 40.
The output shift register 22 includes a chain of twenty
magnetic cores 97 through 116 arranged in two rows of
graph code. The converted code character is .applied
in a manner to be described.
ten magnetic cores each. As in the case of the other mag
The remaining magnetic cores in the space shift reg
netic core shift registers included in the circuit of the
ister 17 are connected together and operate in the same
invention, the operation of the output shift register 22
manner as the magnetic cores 40, 41. By ñrst applying
is similar to that described in connection with the space
a"`shift current pulse to the shift windings on the even
numbered magnetic cores constituting the line of storage 40 shift register 17. The odd numbered magnetic cores con
stitute a line of storage cores, while the even numbered
cores and then applying a shift current pulse to the shift
magnetic cores constitute a line of temporary storage
windings on the odd numbered magnetic cores constitut
cores. A “one” inserted in a magnetic core of the output
ing the line of temporary storage cores, a “one” is ad
shift register 22 is advanced core-by-core along the chain
vanced from core to core along the chain of magnetic
of magnetic cores 9‘7 through 116 in response to shift
cores. Thef‘one” is advanced out of a magnetic core
current pulses applied at first to the shift windings on
in the line of storage cores and into a magnetic core in
the line of storage cores and, thereafter, to the shift wind
the line of temporary storage cores. Upon the applica
ings on the line of temporary storage cores.
tion of .a shift current pulse to the shift windings on the
The distributing circuit 12, error detecting circuit 14,
magnetic cores in the line of temporary storage cores,
the “one” is advanced out of the magnetic core in the line 50 mark shift register 1‘5, space shift register 17, code con
verter 19 and output shift register 22 are operated in
of temporary storage cores and into the next magnetic
proper time sequence in response to current pulses ap
core in the line of storage cores, .and so on.
plied thereto from a second driving unit 27. The driv
The mark shift register 15 includes a chain of fourteen
ing unit 27 includes gating triode vacuum tubes 117
magnetic cores 65 through 78 arranged in two rows of
through 119, blocking oscillator triode vacuum tubes 120
seven magnetic cores each and is similar in construction
and operation to that of the space shift register 17. The 55 through 122 and driving triode vacuum tubes 123 through
125. Driving unit 27 functions to supply the required
odd numbered magnetic cores constitute a line of storage
current pulses in response to the operation of the timing
cores, while the even numbered magnetic cores constitute
wave generator 26 in a manner to be described. In the
a line of temporary storage cores. A “one” inserted in
interests of conservation of space, various ones of the
the first magnetic core 65 is advanced core-by-core along
the chain of magnetic cores 65 through 78 in the same 60 triode vacuum tubes inc‘luded in the circuit of the inven
tion which are similar in construction and function may
manner as described in connection with the space shift
be combined in actual practice as duo-triode vacuum
register >17 .
tubes. This construction has been shown in the drawing
The error detecting circuit 14 includes a mutilation
shift register, indicated generally by the reference nu
meral 79, and a single magnetic core 3f). rlîhe mutila
tion shift register 79 includes seven magnetic cores 81
through 87 arranged in a first row of four magnetic cores
and in _a second row of three magnetic cores. The op
eration of the mutilation shift register 79 is similar to that
wherever possible.
In the operation of the invention, a first train of tim
ing pulses of predetermined frequency including the pulses
P3' through P20" shown by the smaller arrows in FIG
URE 3 is applied from the timing wave generator 26 to
the control grid of the tube 118 over an electrical path
described, in detail, in connection with the space shift 70 including lead 126 and coupling capacitor 127. The
register 17. The odd numbered magnetic cores con
timing pulses may, for example, occur at approximately
stitute a line of storage cores, while the even numbered
208 microsecond intervals. The gating tube 118 is nor
magnetic cores constitute a line of temporary storage
mally biased beyond cut off, and is rendered conducting
cores. A “one” inserted in the first magnetic core 81 is
advanced core-by-core along the chain of magnetic cores .75 in response to each timing pulse applied to the control
3,055,978
grid thereof from the timing Wave generator 26. During
the intervals in which the tube 118 is conducting, current
is caused to flow over lead 128 and through the primary
10
of each of the timing pulses supplied by the timing wave
generator 26 over lead 164. During the periods in which
winding 129 of a magnetic core transformer 130 included
tube 119 is conducting, current is caused to flow over
tube 121, raising the potential on the control grid to a
level such that tube 121 conducts. As the current through
the same manner as described in connection with tube
in the plate circuit of the blocking oscillator tube 121. UI lead 166 and through the primary winding 167 of a
transformer 163 included in the plate circuit of the biocli
A positive voltage is induced in the secondary winding 131
ing oscillator tube 122. The tube 122 operates in exactly
of transformer 130 which is applied to the control grid of
121. A positive pulse is produced by the operation of
tube 122 which is applied to the control grid of the
10 driving tube 125 over an electrical path including lead
applied to the control grid of tube 121 also increases
169. The tube 125 functions to produce a negative, shift
until a point of saturation is reached. The current through
current pulse in the plate circuit thereof for each positive
the primary winding 129 stops increasing, and a positive
pulse applied to its controi grid. A series of shift cur
voltage is no longer induced across the secondary wind
rent pulses appears in the plate circuit of tube 125. At
ing 131. A charge on capacitor 132, built up during the
the time that the above circuit operations are occurring,
time that voltage was being induced in the secondary
the positive pulses produced by the operation of tube
winding 131, leaks olf onto the control grid of tube 121.
122 are also applied from the control grid of tube 122
Tube 121 continues to conduct until the control grid goes
to the control grid of a driving, triode vacuum tube 170
negative with respect to the cathode. A sharp, positive
over an electrical circuit including lead 171 and resistor
pulse of a duration determined largely by the transformer
172. Tube 170 is rendered conducting in response to
magnetizing inductance and to a lesser degree by the value
each of the positive pulses applied to the control grid
of capacitor 132 is produced which is applied over lead
thereof such that a series of negative, shift current pulses
133 from the control grid of tube 121 to the control grid
appears in the plate circuit of the tube 170. The shift
of the driving tube 124. Tube 124 becomes conducting.
current pulses appearing in the respective plate circuits
The positive pulse applied to the control grid of tube 124
of tubes 125 and 170‘ will be one hundred and eighty de
is amplified, and appears as a negative, shift current pulse
grees out of phase, in time relation, with the shift cur
in the plate circuit of tube 124. In this manner, a series
rent pulses appearing in the respective plate circuits of
of shift current pulses appears in the plate circuit of tube
tubes 124 and 149.
the primary winding 129 increases, the positive voltage
124.
As each shift current pulse is produced by the opera
tion of tube 124, current flows over an electrical path
including lead 134, the shift windings 55 and 135- through
140 on the magnetic cores 40, 42, 44, 46, 48, 50 and
52, respectively, in the space shift register 17, the shift
windings 141 through 147 on the magnetic cores 65, 67,
69, 71, 73, 75 and 77, respectively, in the mark shift
register 15 and the input winding 148 on magnetic core
88 in the distributing circuit 12. The Voltage induced
in the input winding 148 upon the reception of each of
the shift current pulses causes a “one” to be inserted in
the magnetic core 88.
In addition to the above circuit operations, each posi
tive pulse produced by the operation of tube 121 is ap
plied from the control grid of tube 121 to the control
grid of a driving triode vacuum tube 149 over an elec
trical path including lead 150 and resistor 151. Tube
149 conducts in response to each positive pulse applied
to the control grid thereof from the control grid of tube
121, and a series of shift current pulses appears in the
plate circuit of tube 149. As each shift current pulse i
is produced by the operation of tube 149, current flows
over an electrical path including lead 152, the shift wind
ings 153 through 162 on the magnetic cores 98, 100, 102,
104, 106, 108, 110, 112, 114, and 116, respectively, in
the output shift register 22 and the input winding 163
on the magnetic core 80 included in the error detecting
circuit 14. The voltage induced in the input winding 163
upon the reception of each shift current pulse causes a
“one” to be inserted in the magnetic core 80. There
fore, a “one” is inserted in the magnetic cores 80, 88 in
In describing a complete cycle of operation, it will be
assumed that a “one” has -been inserted in the magnetic
cores 80, 88 as a result of the circuit operations outlined
above in response to the application of 'a timing pulse
P2’ from the timing wave generator 26 to the control
grid of gating tube 118. While the timing pulse P2’ is
not shown in- FIGURE 3, it is to be understood that
such a pulse P2’ will be supplied ‘by the timing Wave gen
erator 26 to the control grid of »tube 118 one half cycle
at the operating frequency before the appearance of the
timing pulse P3 lat the control grid of tube 119. It will
be further assumed that a “one” has been inserted in the
magnetic core 81 and that a “Zero” is stored in the re
maining magnetic cores 82 through 87 of the mutila
tion shift register 79 'by circuit operations to be described.
The reception of the timing pulse P3 causes tube 119 to
conduct. A negative pulse is applied from the plate of
tube 119 to the plate circuit of tube 1122, and tube 122
conducts. A positive pulse is applied from the control
grid of tube 122 to the control grid of :tube 125, causing
tube 125 to produce a shift current pulse in its plate
circuit. Current flows over an electrical path including
lead 175, the shift windings 60 and 176 through 181
on magnetic cores 41, 43, 45, 47, 49, 51 and 53, re
spectively, in the space shift register »17, the shift wind
ings 182 through 88 on the magnetic cores 66, 68, 70,
72, 74, 76 and '78, respectively, in the mark shift regis
ter 15, the shift Iwinding 189 on magnetic core 90, the
shift winding 190 on magnetic core 89‘ and the shift
winding 191 on magnetic core 88.
At the `same time, the positive pulse «appearing at the
response to the shift current pulses produced as a result 60 control grid of tube 122 is applied to the control grid
of tube 170 over lead 171, and a shift current pulse is
of each positive pulse appearing at the control grid of
produced in the plate circuit of tube 170. Current flows
over an electrical path including lead 192, the shift wind
A second train of timing pulses including the timing
pulses P3 through P21 shown by the larger arrows in 65 ings 193 through 202 on the magnetic cores 97, 99, 101,
103, 105, 107, 109, 111, 113 and 115, respectively, in
«FIGURE 3 is applied from the timing wave generator
the `output shift register 22 and the shift windings 203
26 to the control grid of the gating tube 119 over an
through 205 on the magnetic cores 82, 84 and 861, re
electrical path including lead 164 and coupling capacitor
spectively,
in the mutilation shift register 79. The voltage
165. The timing pulses applied to the control grid of
induced in the shift winding 191 on the magnetic core 88
tube 121.
tube 119 occur at regu'lar time intervals such that each
of the timing pulses is applied to the control grid of tube 70 in the distributing circuit 12 causes the “one” stored in
119 one half cycle at the operating frequency before a
timing pulse of the Ifirst train is applied to the control
grid of tube 118. Tube 119 is normally biased beyond
cut off, and is rendered conducting upon the reception 75
L
the magnetic core 88 to 'be `advanced out of the core.
Current flows over an electrical path including the out
put winding 206 on the magnetic core 88, rectifier 207,
lead 208 and the input winding 54 on the first magnetic
core 40 in the space shift register 17. A “one” is in
3,055,978
11
serted in the first magnetic core 40 of the space shift
register 17, while a “Zero” is stored in the magnetic core
88 of the distributing circuit 12. No further circuit opera
tions occur at this time, and the “one” stored in the mag
voltage induced in the input windings 214, 215 on mag
netic cores 90, 89, respectively, causes a “one” to be in
serted into each of the magnetic cores 89, 90.
While the above circuit operations are occurring, the
appearance of the timing pulse P4’ on the control grid
Ynetic core `81 and in the magnetic core 80 of the error
of tube 118 causes a shift current pulse to be produced
detecting circuit 14 remain undisturbed.
in the plate circuit of tube 124. Voltage is induced in
In describing the operation of the invention in response
the shift `windings 55, 135 on the magnetic cores 40, 42,
-to the reception of a code character, it will be assumed
respectively, in the space shift register 17 such that the
that the next code character in an incoming telegraph
“one” stored in the respective cores is advanced into the
message signal is the letter character S of the seven-unit 10 succeding magnetic cores in the chain thereof included in
telegraph code. However, the operation will be similar
the space shift register 17. The “one” is advanced out
to that described upon the reception of any other code
of magnetic core 42 and into magnetic core 43, while the
character of the seven-unit telegraph code. The letter
“one” is advanced out of magnetic core 40 and into mag
character S of the seven-unit telegraph code includes the
netic core 41. A Voltage is also induced in the input
second, fourth and sixth elements as marking and `the
winding 148 on magnetic core 88 of the distributing cir
first, third, fifth and seventh elements as spacing. The
cuit 12, causing a “one” to be inserted into the magnetic
signal elements are applied in series from suitable receiv
core
88.
ing equipment to input terminal 11i’ such that they coin~
The neXt timing pulse P5 applied to the control grid
cide in time with the timing pulse P3’ through P20’ ap
of tube 119 from the timing wave generator 26 over
plied to the control grid of tube 118 from the timing 20 lead 164 causes a shift current pulse to appear in the
wave generator 26. In the cycle of operation to be de~
plate circuit of tube 125. The “one” stored in each of
scribed, the first signal element `of the letter character S,
the magnetic cores 41, 43 of the space shift register 17
namely, a spacing element, is applied to the input 1ter
is advanced into the succeeding magnetic cores 42, 44,
minal 10 at the same time that the timing pulse P3’ is
respectively, in the chain thereof. A voltage is induced
25
»applied to the control grid of tube 118. As the first sig
in the shift windings 189, 1911 and 191 on the magnetic
nal element is a spacing element, that is an interval dur
cores 90, 89 and 88, respectively, in the distributing cir
ing which no current iiows, no change in the status of
cuit 12 over lead 175. The “one” is advanced out of
the circuit ‘occurs in response to the reception of the iirst
the magnetic core 9i? and into the first magnetic core 65
signal element. However, the application of the timing
in the mark shift register 15 over an electrical path in
pulse P3’ to the control grid of tube 113 results in the 30 cluding output winding 216 on magnetic core 9b, lead
production of a shift current pulse in the plate circuit
217, rectifier 218 and the input winding 219 on the
of tube 124. Voltage is induced in the shift winding 55
magnetic core 65. The voltage induced in the shift
on magnetic core 4t? in the space shift register 17 and in
windings 1911, 191 on magnetic cores 89, 88, respectively,
the input winding 148 on magnetic core 88 in the dis
causes a “one” to be advanced out of the respective cores
tributing circuit 12. rl'he “one” stored in magnetic core
at the same time. The output winding 2211 on the mag
«40 is advanced into the magnetic core 41 of the space
netic core 89 is connected in parallel with the output
shift register 17, and a “one” is inserted in the magnetic
winding 206 on the magnetic core 88 with respect to
core 88 in the manner previously described. A “zero”
ground. The terms ground, as used in the specifica
is now stored in the magnetic core 4t) of the `space shift
40 tion, is to be understood as refering to a point of fixed
register 17.
reference potential. As indicated by the location of the
As shown in FIGURE 3, the neX-t timing pulse P4 is,
dots adjacent the respective windings 228, 2116, the cur
thereafter, applied to the control grid of tube 119 from
rent flowing through one of the output windings is of a
the timing wave generator 26. A shift current pulse
polarity opposite to that íiowing through the other out~
appears in the plate circuit of tube 125. Voltage is in
put winding. ln other words, the output of the mag
duced in the shift winding 6i) on the magnetic core 41
netic core 89 is phased in the opposite sense with re
in the space shift register 17 and in the shift windings 189,
spect to ground as compared to the output of the mag
190 and 191 on the magnetic cores 90, 89, and 88, re
netic core 88. By alternating current transformer theory,
spectively, in the distributing cincuit 12. The “one”
the flux linkages cancel one another such that the net
stored in the magnetic core 41 is advanced into the mag
output of the two magnetic cores with respect to ground
netic core 42 of the space shift register 17 , while the “one” 50 is substantially zero. No effective energy is applied to
stored in the magnetic core 88 is inserted over lead 208
into the magnetic core 40.
the input winding S4 on the magnetic core 4i) of the
space shift register 71 over lead 28S and a “one” is not
inserted in the magnetic core 40.
At the time of the timing pulse P5, a shift current
The second signal element of the letter character S
is -applied to the input terminal 10 4simultaneously with
the appearance of the timing pulse P4’ on the control 55 pulse also appears in the plate circuit of tube 170. A
grid of tube 118. The second signal element is marking
voltage is induced in the shift winding 2113 on the mag
and, therefore, a current pulse is applied from the ter
netic core 82 in the mutilation shift register 79 over lead
minal 10 to the control grid of gating tube 91. Tube 91
192. The “one” is advanced out of the magnetic core
which is normally biased beyond cut-off conducts in re
sponse to the current pulse, and a negative pulse is ap 60 "o2 and into the succeeding magnetic core 83 in the chain.
At this time, therefore, a “one” is stored in the magnetic
plied «from the plate circuit of tube 91 to ythe plate circuit
core 44 in response to the reception of the timing pulse
of blocking oscillator tube 92 over lead 147. A positive
P2’ and in the magnetic core 42 of the space shift reg
pulse is produced by the operation of tube 92 which is
ister 17 representing the first signal element, a spacing
applied to the control grid of driving tube 93 over lead
148.
Tube 93 conducts, causing a negative, shift cur
element.
A “one” is stored in the magnetic core 65 of
65 the mark shift register 15 representing the second signal
rent pulse «to appear in the plate circuit thereof. Current
element, a marking element. ln addition, the “one” in
flows over an electrical path including lead 209', the shift
the mutilation shift register '79 is now stored in the mag
windings 210 through 213 on the magnetic cores 81, 83,
netic core 83, indicating that one marking element in
S5 and 87, respectively, in the mutilation shift register 79
and the input windings 214, 215 on magnetic :cores 90, 70 the letter character S has vbeen counted.
The circuit operations which follow upon the recep
89, respectively, in the distributing circuit 12. The volt
tion of the third through seventh signal elements in the
age induced in the shift winding 210 on the magnetic
letter character S are similar to those described. Upon
the reception of a spacing element, a “one” is inserted
in the first magnetic core 4@ of the space shift register
Ymagnetic core 82 of the mutilation shift register 79. The 75
core `81 in the mutilation shift register 79 causes the “one”
stored in the magnetic core `81 to be advanced into the
3,055,978
13
14
17. Upon the reception of a marking element, a “one”
is inserted in the first magnetic core 65 of the mark shift
register 15, a cancellation of the outputs of the other
magnetic cores 89, 88 in the distributing circuit 12 taking
place such that the magnetic core 40 retains its status
in which a "Zero” is stored therein. Thus, the reception
For each signal element received, therefore, a “one”
is stored in a magnetic core of either the mark shift regis
ter 15 or the space shift register 17 but not both. Since
a “one” is inserted in -the first magnetic core 65 and ad
vanced through the mark shift register 15 for each mark
ing element received, the magnetic cores having a “one”
stored therein are arranged in the mark shift register 15
according to the order in which the marking elements
of the third signal element, a spacing element, and of
the timing pulses P5', P6 results in a “one” being stored
in the magnetic cores 46, 44 and' 4t) of the space shift
appear in Ithe incoming code character. Since a “one”
register 17. The “one” originally stored in magnetic 10 is inserted in the first magnetic core 4t) and advanced
core 65 is advanced first into magnetic core 66 and,
through the space shift register 17 for each spacing ele
thereafter, into the magnetic core 67 of the mark shift
ment received, the magnetic cores having a “one” stored
register 15. Upon the reception of the fourth signal ele
therein are arranged in the space `shift register 17 accord
ment, a marking element, and of the timing pulses P6',
ing to the order in which the spacing elements appear in
P7, a “one” is stored in the magnetic cores 48, 46 and
the incoming code character. The code character, name
42 of the space shift register 17. A “one” is stored in
ly, the letter character S in the example given, is estab
the magnetic cores 69, 65 of the mark shift register 15.
lished in the mark and space shift registers 15, 17, respec
In addition, the “one” stored in the magnetic core 83
tively, in binary form during the interval of time between
will be first advanced into the magnetic core 84 and,
the timing pulses P3' through P10 shown in FIGURE 3.
thereafter, into the magnetic core 85 of the mutilation 20 Upon the reception of the timing pulse P10', the “one”
register 79, indicating that the second marking element
stored in each of the magnetic cores 52, 48, 44 and 40
in the letter character S has been counted.
is advanced into the magnetic cores 53, 49, 45 and 41,
Following the reception of the fifth signal element, a
respectively, of the space shift register 17. The “one”
spacing element, and' of the timing pulses P7', P8, a
stored `in each of the magnetic cores 75, 71 and 67 is
“one” is stored in the magnetic cores Si), 4S, 44, 40 of
advanced into the magnetic cores 76, 72 and 68, respec
the space shift register 17, while a “one” is stored in the
tively, of the mark shift register 15.
magnetic cores 71, 67 of the mark shift register 15. The
To review, a “one” is now stored in the magnetic core
reception of the sixth signal element, a marking element,
S7, indicating that three marking elements have been
and of the timing pulses P8', P9 causes a “one” to be
counted, and in the magnetic core 80 of the error de
stored in the magnetic cores 52, 50, 46 and 42 of the 30 tecting circuit 14. In this connection, it should be noted
space shift register 17, and a “one” to be stored in the
that the “one” stored in the magnetic core 80‘ will be
magnetic cores 73, 69 and 65 of the mark shift register
reinforced upon the appearance of each shift current
15. The “one” stored in the magnetic core S5 is first
pulse in the plate circuit of tube 149. The binary in
advanced into the magnetic core 86 and, thereafter, into
formation corresponding to the received letter character
the magnetic core 87 of the mutilation shift register '79,
S stored in the mark and space shift registers 15, 17, re
indicating that the third marking element in the letter
spectively, is ready for application to the diode matrix 19.
character S has been counted. The reception of the
Each of the temporary storage magnetic cores 78, 76, 74,
seventh and final signal element, a spacing element, and
72, 71), 68 and 66 in the mark shift register 15 is con
of the timing pulses P9', P10 causes a “one” to be stored
nected
over identical electrical circuits including leads
in the magnetic cores 52, 4S, 44 and 46 of the space
shift register 17, representing the first, third, fifth and
223 through 229, respectively, to separate input terminals
seventh signal elements of the letter character S as spac
ing. A “one” is stored in the magnetic cores 75, 71 and
an electrical circuit is completed from the magnetic core
1M through 7M of the diode matrix 19. For example,
78 to the input terminal 1M including output windings
230, 231, lead 223, resistor 232 and capacitor 233 by
67 of the mark shift register 15, representing the second,
fourth and sixth signal elements of the letter character
S as marking.
Referring to the space shift register 17, the output
winding 221 on the last magnetic core 53 in the chain
of magnetic cores therein is series connected with a ter
minating resistor 222. As a “one” is advanced out of
passed to ground, and so on.
45
Each of the temporary
storage magnetic cores 53, 51, 49, 47, 45, 43 and 41 in
the space shift register 17 is connected over similar elec
trical circuits including leads 234 through 240, respec
tively, to the input terminals 1S through 7S of the diode
the magnetic core 53, it is, therefore, terminated across 50 matrix 19. Thus, the magnetic core 53 is connected to
input terminal 1S over an electrical circuit including out
the resistor 222. For example, the “one” originally in
put windings 241, 242, lead 234, resistor 243 and capaci
serted in the space shift register 17 upon the reception of
tor 244 by-passed to ground, and so on. It is clear that,
the timing pulse P2' is advanced out of the magnetic core
as the shift curren-t pulses appearing in the plate circuit
53 and terminated across the resistor 222 upon the re
ception of the timing pulse P10. In this manner, any 55 of tube 125 are applied to the shift windings on the tem
porary storage cores in the respective shift registers 15, 17
information in the form of a “one” stored' in one or more
upon the `reception of the timing pulses P3 through P16),
of the magnetic cores 40 through 53 prior to the recep
a parallel output is obtained which is presented to the in
tion of the letter character S is completely cleared out of
put terminals 1M through 7S of the diode matrix `19.
the space shift register 17 when all of the signal elements
in the letter character S are received. The only infor 60 The output will vary as the information in the form of
“ones” representing the signal elements received is ad
mation stored in the space shift register 17 following the
vanced core-by-core along the chains of magnetic cores
reception of the timing pulse P10 will be that corre
in the respective shift registers 15, 17. The diode mat
sponding to the arrangement of spacing elements in the
rix 19, however, is controlled such that it cannot accept
letter character S. A “one” is stored in the magnetic
cores 52, 48, 44 and 40, the remaining magnetic cores in 65 the signal energy applied to the input terminals 1M
through 7S unless and until a battery is connected there
the space shift register 17 having a “zero” stored therein.
to. The battery is supplied to the diode matrix 19 only
The construction and operation of the mark shift reg
at the time of the timing pulse P11, and, therefore, the
ister 15 is similar to that described in connection with
diode matrix 19 remains inoperative in response to the
the space shift register 17. The only information stored
parallel output of the shift registers 15, 17 while the in
in the mark shift register 15 following the reception of
the timing pulse P10 will be that corresponding to the 70 coming letter character S is being established in the shift
registers 15, 17 in binary form.
arrangement of marking elements in the letter character
The application of the timing pulse P11 from the tim
S. A “one” is stored in the magnetic cores 75, '71 and
ing wave generator 26 to the control grid of tube 119 over
67, the remaining magnetic cores in the mark shift reg
lead 164 causes a shift current pulse to appear in the
ister 15 having a “zero” stored therein.
75 plate circuit of tube 125. The “ones” stored in the mag
3,055,978
16
netic cores 76, 72 and 68 of the mark shift register 15
are advanced out of the respective magnetic cores such
that a current pulse is applied to the input terminals 2M,
beyond cut-off. Upon the application of the current
pulses to the control grids thereof, tubes 268, 270, 271
conduct. The respective plates of tubes 267 through
4M and 6M of the diode matrix 19 over leads 224, 226
274 are connected to input windings on the magnetic
and 228, respectively. At the same time, the “ones”
stored in the magnetic cores 53, 49, 45 and 41 of the
space shift register 17 are advanced out of the respective
magnetic cores such that a current pulse is applied to
the input terminals 1S, 3S, 5S and 7S of the diode matrix
19 over leads 234, 236, 238 and 240, respectively. The
input terminals 1M through 7S are paired such that each
pair includes a marking terminal and a spacing terminal.
Seven pairs of terminals are provided each representing
cores 114, 112, 110, 108, 106, 104, 100, 98 ofthe output
shift register 22 over leads 281 through 288 respectively.
When one or more of the gating tubes 267 through 274
is rendered conducting by the application of a current
pulse to the control grid thereof from the diode matrix
19, a negative, current pulse is applied from the plate
circuit of the conducting tube to the input winding on
the magnetic core in the output shift register 22 to which
it is connected. In the example given, tubes 268, 270,
271 conduct. A current pulse is applied from the -plate
a signal element included in an incoming code character.
vA current pulse is applied to one of the terminals in each 15 circuit of tube 268 to the input windings 289, 290 on
the magnetic core 112 of the output shift register 22
pair depending upon whether the corresponding signal
over lead 282. A current pulse is also applied from the
element is marking or spacing. The letter character S in
plate circuit of tube 270 to the input windings 291, 292
cludes the first, third, iifth and seventh elements as spac
on the magnetic core 108 of the output shift register 22
ing and the second, fourth and sixth elements as marking.
Therefore, a current pulse is applied in the example given 20 over lead 284. In addition, a current pulse is applied
from the plate circuit of tube 271 to the input windings
to the input terminals 1S, 2M, 3S, 4M, 5S, 6M and 7S
293, 294 on the magnetic core 106 of the output shift
of the diode matrix 19.
register 22 over lead 285. A “one” is inserted in the
Simultaneously with the application of the timing pulse
magnetic cores 112, 108 and 106 of the output shift
P11 to the control grid of tube 119, the timing wave gen
erator 26 functions to apply the timing pulse P11 to the 25 register 22.
While the above circuit operations are occurring, the
control grid of the gating tube 117 over an electrical
positive pulse appearing at the control grid of ytube 120
circuit including llead 251 and coupling capacitor 252.
is applied to the control grid of a driving triode vacuum
A negative pulse is applied from the plate of tube `117
tube 295 over an electrical path including lead 255, lead
to the plate circuit of blocking oscillator tube 120 over
lead 253. The tube 120 functions to produce a positive 30 296 and resistor 297. Tube 295 conducts such that a
negative, current pulse is applied from the plate circuit
pulse which is applied from the control grid of tube 120
to the control grid of a cathode follower tube 254 over
an electrical circuit including lead 255, lead 256 and re
of tube 295 to the positive terminal of a source of po
tential over an electrical circuit including lead 298, the
senting the letter character S of the seven-unit telegraph
register 22.
input windings 299, 300 on the magnetic core 116 of
sistor 250. A positive pulse is applied from the cathode
of tube 254 to the diode matrix 19, as battery, over an 35 the output shift register 22 and the input windings 301
through 303 on the magnetic cores 85, 83, and 81, re
electrical circuit including a current boosting transformer
spectively, in the mutilation shift register 79. A “one”
257 and lead 258. The diode matrix 19 thereupon func
is inserted in the magnetic core 116 of the output shift
tions to convert the binary information received repre
The polarity of the input windings 301,
code into the letter character S of the five-unit code. The 40 302 is such that the status of the magnetic cores 85, 83,
respectively, having a “zero” stored therein, is confirmed.
operation of the diode matrix 19 is similar to that de
The polarity of the input winding 303 on the magnetic
scribed in detail in Patent Number 2,724,739 issued on
core 81 is determined such that a “one” is inserted in
November 22, 1955, to J. S. Harris for Code Conversion
the magnetic core 81. The “one” ywill remain stored in
System, and need not, therefore, be described in detail
at this time. The diode matrix 19, per se, forms no part 45 the magnetic core 81 of the mutilation shift register 79
until the next code character is received. At that time
of the instant invention.
a new count of the marking elements included in the
The letter character S in the five-unit telegraph code
subsequent code character will be made, causing the
includes the iirst and third elements as marking, while
“one” to be advanced out of the magnetic core 81 and
the second, fourth and iifth elements are spacing. The
diode matrix 19 is designed to supply a current pulse at 50 along the chain of magnetic cores in the mutilation shift
register 7 9 in the manner described above.
the respective outpu-t terminals thereof for each spacing
In addition to the above circuit operations, the timing
element and no current pulse at the respective output ter
pulse P11 performs still another function. A “one” is
minals thereof for each marking element. A current
at this itme stored in the single magnetic core 80 ‘and in
pulse will, therefore, appear at the output terminals 2,
4 and 5. In addition to the five numbered signal element 55 the last magnetic core 87 of the mutilation shift register
79 in »the error detecting circuit 14. As described above,
output terminals, the diode matrix -19` includes the output
the application of the timing pulse P11 to the control
terminals labeled Signal I, Alpha and Beta. A current
grid of tube 117 from the timing wave generator 26 over
pulse appears at one of the last-mentioned output ter
lead 251 causes a positive pulse -to be produced by oper
minals in response to the reception by the diode matrix
19 of a corresponding control function character of the 60 ation of tube 120. The positive pulse is applied from
the control grid of tube 120 to the control grid of driving
seven-unit telegraph code. The respective output ter
tube 123 over lead 304. A shift current pulse appears
minals of the diode matrix 19 are connected over iden
in the plate circuit of tube 123. Current iioWs over an
tical circuits including leads 259 through 266 to the con
electrical circuit including lead 305, the shift winding 306
trol grids of separate gating triode vacuum tubes 267
through 274, respectively. In the example given, a cur 65 on magnetic core 80 and the shift winding 307 on mag
netic core 87, causing the “ones” to be advanced out of
rent pulse is applied from the output terminal 2 of the
the respective magnetic cores 80, 87. The output wind
diode matrix 19 to the control grid of tube 268 over the
ings 308, 309 on the magnetic cores 87, 80, respectively,
electrical circuit including an integrating network com
are series connected, and are mounted on the respective
prising resistor 275 and capacitor 276, a back-biasing net
work including resistors 277, 278 and capacitor 279, cou 70 magnetic cores 87, 80 such that the output of the mag
netic core 87 is opposite in phase with respect to ground
pling capacitor 280 and lead 260. A current pulse is also
as compared to the output of the magnetic core 80. The
applied from the output terminals 4 and 5 to the respec
net flux linkages of the two magnetic cores 87, 80 becomes
tive control grids of tubes 270, 271 over similar electrical
circuits including leads 262, 263, respectively.
The gating tubes 267 through 274 are normally biased 75
substantially Zero.
The shift windings 308, 309 are included in an elec# `
17
3,055,978
trical circuit forming a load for the cathode follower
tube 254, the electrical circuit also including lead 310,
resistor 311, capacitor 312 try-passed to ground, rectifier
313, resistor 314 and the current boosting transformer
257. The junction of the resistor 314 and rectifier 313 is
connected «to the control grid of a driving -triode vacuum
tube 315 over an electrical circuit including rectifier 316,
a network including resistor 313 and capacitor 317, lead
319, coupling capacitor 329 and resistor 321. As Will
be discussed, the tube 315 yfunctions to insert a “one” in
the mutilation magnetic core 102 of the output shift
18
22 is advanced core-by-core such that it is cleared out of
the output shift register 22. Upon the reception of the
timing pulse P12', no voltage is induced in the output
winding 322 on the magnetic core 116, tube 323` remains
cut-off and an interval of current flow or marking element
appears at the output terminal 329; upon the reception of
timing pulse P13', voltage is induced in the output winding
322, tube 323 conducts and an interval of no current flow
or spacing element appears at the output terminal 329;
upon the reception of the timing pulse P14', no voltage is
induced in the output Winding 322, tube 323 remains cut
register 22 when a mutilated or erroneous character is
off and an interval of current flow or marking element ap
detected by the error detecting circuit 14. It has been
assumed so far, however, that three marking elements
have been counted by the mutilation shift register 79 in
dicating the reception of a proper code character. In
this situation, the cancellation of the flux linkages by
pears at output terminal 329; and upon the reception of
the timing pulses P15', P16', voltage is induced in the out
put winding 322, tube 323 conducts and two successive
intervals of no current flow or spacing elements appear at
the output terminal 329.
The letter character S of the
the simultaneous advancement of a “one” out of the
five-unit telegraph code comprising the first or start ele
magnetic cores 80, 87 effectively produces a ground con
ment as spacing, the first and third signal elements as mark
nection such that current flows over the electrical cir 20 ing and the second, fourth and fifth signal element-s as
cuit including resistor 314, rectifier 313, capacitor 312
by-passed to ground, resistor 311, lead 310 and the shift
windings 369, 3118 on the magnetic cores 8G, 87, respec~
tively. A positive pulse is not lapplied to the control
grid of tube 315. Tube 135 which is normally biased 25
beyond cut-off remains quiescent, and a “one” is not in~
serted into the mutilation magnetic core 102 of the out
put shift register 22.
The letter character S of the five»unit telegraph code
spacing appears at the output terminal 329 for application
to `a utilization circuit.
The circuit operations which occur upon the reception
of any correct code character of the seven-unit telegraph
code are the same as outlined above. The code character
is received, converted and applied to the output terminal
329, the error detecting circuit 14 functioning to deter
mine that the incoming code character includes three
marking elements. If the control function character Sig
is now ready to be advanced out of the output shift 30 nal I of the seven-unit telegraph code is received, the diode
register 22 and applied to a utilization circuit. Upon
matrix 19 functions `to insert a “one” in the magnetic core
the application of the timing pulse P11' to the control
grid of tube 118, a shift current pulse appears in the
104 of the output shift register 22 by causing tube 272 to
conduct in response to a pulse applied to the control grid
plate circuit of tube 149.
thereof over lead 264. Tube 273 is made to conduct upon
Current flows over the elec
trical circuit including lead 152, the shift windings 162, 35 the reception of the control function character Alpha of
169, 158 and 157 on the magnetic cores 116, 112, 108
the seven-unit telegraph code, and a “one”_ is inserted in
and 106, respectively, of the output shift register 22 and
the magnetic core `98 of the output shift register 22. The
the input Wind-ing 163 on the magnetic core 80 of the
reception of the control function character Beta of the
error detecting circuit 14. A “one” is inserted into the
seven-unit telegraph code causes tube 274 to conduct, and
magnetic core Si) and is reinforced upon the appearance 40 a “one” is inserted in the magnetic core 100 of the output
of each subsequent shift current pulse in the plate circuit
shift register `22. As there is, in effect, no conversion to
of tube 149 in the manner already described. The
a five-unit code character upon the reception of the three
“ones’7 stored in the magnetic cores 116, 112, 188 and
last-mentioned code characters of the seven-unit telegraph
106 are advanced out of these magnetic cores and into
code, current pulses will not appear on any of the signal
the succeeding magnetic cores in the chain thereof in 45 output terminals 1 through 5 in these instances. A “one”
the output shift register' 22 such that a “one” is stored
will be stored in the start magnetic core 116 and in only
in the magnetic cores 113, 109 and 197. It will be re
one of the other magnetic cores 97 through 115 in the
membered that a “one” was stored in the last magnetic
output shift register 22, depending upon Which of the
core 116 of the output shift register 22 upon the reception
control function characters Signal I, Alpha or Beta of
of the timing pulse P11. A voltage is induced in the 50 the seven-unit telegraph code has been received. When the
output 'winding 322 on the magnetic core 116 such that
output shift register 22 is cleared `of the information stored
a positive pulse is applied to the control grid of a gating
therein, a control pulse will appear at the output terminal
triode vacuum tube
23 over an electrical circuit includ
329 at a time determined according to which one of mag
ing lead 324, rectifier 325, a network connected to ground
netic cores 104, 100 or 98 has had a “one” stored therein.
including resistor 32u and capacitor 327 yand coupling ca 55 The utilization circuit or equipment connected to the out
pacitor 328. Tube 323 which is normally biased beyond
put terminal 329 can be designed to operate in response to
cutoff conducts. As a result, an interval of no current
the control pulse to perform the function desired.
flow or spacing element appears at the output terminal
The description has been directed up to this point to the
329. This spacing element is designated as the start
operation of the invention upon the reception of a correct
element `for the five-unit code character to follow.
code character »of the seven-unit telegraph code, that is a
The following circuit operations can be determined
code character including three mm‘king elements. When a
from the description already given. Current will flow
distorted code character of the seven-unit telegraph code
through the shift `windings 193 through 202 on the mag
is received, that is a code character including more than or
netic cores 97, 99, 101, `183, `105, 107, 1119, .111, 113 and
less than three marking elements, the code character is
115 upon the application of each ofthe timing pulses P12, 65 stored in the mark and space shift registers 15, 17, respec
P13, P14, P715, P16, P17, P18, P19 and P20 from the
tively, in the manner outlined above. As the signal ele
timing Wave generator 26 to the control grid of tube 119.
ments are received, the marking elements are counted by
Current will flow through the shift windings 153 through
the mutilation shift register 79. If the incoming code char
162 on the magnetic cores 98, 101i, 102, 104, 106, 108,
acter includes no marking elements, the “one” remains
110, 112, 114, and V116 upon the application of each of 70 stored in the magnetic core 81 of the mutilation shift regis
the timing pulses P12', P13', P14', P15', P16', P17', P18',
ter 79. If only one marking element is received, the
P19', and P20' to the control grid of tube 118 from the
“one” is advanced out of the magnetic core 81 and into
timing Wave generator 26. The letter character S repre
sented by a “one” and by the absence of a “one” stored
magnetic core 83. If two marking elements are counted,
the “one” is advanced out of the magnetic core 81 and
in certain of the magnetic cores in the output shift register 75 into the magnetic core `85. If more than three marking
3,055,978
2i)
elements are counted, the “one” is completely cleared out
of the mutilation shift register 79 such that a “zero” is
stored in each of the magnetic cores 81 through 87.
When the fourth marking element is received, a voltage
will be induced in the output winding 334 on the magnetic
matically requested to repeat the transmission of the code
character originally received distorted.
At the time of the timing pulse P11, current is applied
to the shift windings 301 through 303 on the magnetic
cores S5, 83, and ‘81, respectively. A “one” is either in
core 87. The “one” stored in the magnetic core 87 at
this 4time is advanced out of the magnetic core 87 and ter
serted in the magnetic core 81 or the presence of a “one”
therein is confirmed in the case where a code character
minated across a resistor 330i. As a result, a “one” is no
previously received included no marking elements. A
longer stored in any of the magnetic cores 81 through 87
“one” stored in the magnetic core `83 or in the magnetic
and can not, therefore, be advanced through the mutila l0 core 85 is advanced out of the respective magnetic cores
tion shift register 79 upon the reception of additional
such that a “zero” is stored therein. Normally, a “one”
marking elements.
advanced out of magnetic core 83 would be inserted in
lf a code character is received including more than or
magnetic core 84, while a “one” advanced out of mag
less than three marking elements, therefore, a “one” will
netic core 85 would be inserted in magnetic core 86.
not be stored in the last magnetic core 87 of the mutilation
However, at the time that timing pulse P11 is received,
shift register 79 at the time of the timing pulse P11. When
tube 170 conducts. Current also flows over the electrical
the timing pulse P11 is received, the binary information
circuit including lead 192 and the shift windings 203
corresponding to the distorted code character received will
through 205 on the magnetic cores S2, 84 and 86, respec
be advanced out of the mark and space shift registers 15,
tively. This action prevents a “one” from being inserted
17, respectively, and into the diode matrix 19. A “one” 20 into any of the magnetic cores 82, 84 and 86. A “one”
is inserted into the magnetic core 116 of the output shift
is, therefore, inserted in magnetic core 81, and the re
register 22. A shift current pulse appears in the plate
maining magnetic cores 82 through 87 in the mutilation
circuit of tube 123 such that current flows over the elec
shift register 79 are each made to have a “zero” stored
trical circuit including lead 305, the shift winding 306 on
therein. At the time of the timing pulse P11', a “one”
magnetic core 80 and the shift winding 307 on the mag 25 is inserted into the magnetic core 80 of the error detect
netic core 87. The “one” stored in the magnetic core 80
ing circuit 14.
is advanced out of magnetic core 80 such that a voltage is
A complete cycle of operation has been described. Re
induced in the output winding 309. As a “zero” is stored
ferring to FIGURE 3, the seven-unit code >character is
in the magnetic core 87, no voltage is induced in the output
received upon the reception of the timing pulses occur
winding 308 on the magnetic core 87 . No cancellation of 30
ilux linkages occurs, and the output of the magnetic core
80 is phased with respect to ground such that current flow
over the electrical circuit including lead 310, resistor 311,
ring during the time interval between the timing pulse
P3 and the timing pulse P10’. At the time of the timing
pulse P11, the conversion of the received code character
takes place, and the number of marking elements counted
in the received code character is checked, including the
capacitor 312 yby-passed to ground and resistor 314 is
blocked.
35 insertion of a “one” into the magnetic core 102 of the
The application of the battery pulse to the diode matrix
output shift register 22 if a distorted code character is de
19 over lead 258 by the `operation of tube 254 causes a
tected. The conversion plus the mutilation signal, if pres
positive pulse to be applied to the control grid of tube 315
ent, is applied to the utilization equipment via output
over the electrical circuit including rectifier 316, the net
terminal 329 upon the reception of the timing pulses oc
work including resistor 318 and capacitor 317, lead 319, 40 curring during the time interval between the timing pulse
coupling capacitor 320 and resistor 321. Tube 315 con
P11’ and the timing pulse P20’. Attention is called to
ducts, and a current pulse is applied from the plate circuit
the fact that the mark and space shift registers 15, 17,
of tube 315 to the input windings 331, 332 on the core 102
respectively, will be cleared of the information stored
of the output shift register 22 over lead 333. A “one” is
therein corresponding to the code character received dur
stored in the magnetic core 102.
In this connection, it should be noted that the tube 315
ing this later time interval. At the end of a cycle of op
eration, a “one” is stored in the magnetic core 80 and in
can conduct only at the time of the timing pulse P11 by
the magnetic core '81 included in the mutilation shift reg
the application of the battery pulse to the diode matrix
ister 79 of the error detecting circuit 14. The circuit of
19. This prevents tube 315 conducting in a situation
the invention is ready to receive and process the next
where more than three marking elements are counted 50 code character of an incoming telegraph message signal.
by the multilation shift register 19, causing a voltage to
It was stated earlier in the description by Way of ex
be induced in the output winding 308 on magnetic core
ample that the timing pulses included in the respective
87 at a time prior to the reception of the timing pulse
trains thereof supplied by the timing wave generator 26
P11. As `a result of this action, a “one” would other
might be 208 microseconds apart in time. Following
wise be inserted in the magnetic core 102 of the output 55 this example, it may be seen, therefore, that a complete
shift register 22 at the wrong time in the sequence of
cycle of operation would require only 3.536 milliseconds.
operation, disrupting the proper operation of the inven
While the invention has been described in connection with
tion.
the conversion of code characters of the seven-unit tele
The conversion `of the ldistorted code character received
graph code into corresponding code characters of the tive
is applied from the `output terminals 1 through 5 to the 60 unit telegraph code, the invention may be used in other
magnetic cores 114, 112, 110, 108 and 106. The diode
applications using different fixed-length telegraph codes
matrix 19 is preferably designed such that a current pulse
without departing from the spirit thereof. The adaption
will not appear at any of the output «terminals Signal I,
of the invention for use in such other applications would
Alpha or Beta upon the reception of a distorted code
only require a corresponding change in the timing se
character. The information stored in the output shift
quence involving engineering skill, an adjustment of the
register 22 is, thereafter, applied to` -the utilization equip 65 number of magnetic cores in the various shift registers,
ment via output terminal 329 in the form of a start
and so on.
element, the conversion of the distorted character fol
A functional block `diagram of a telegraph communi
lowed in time by a control pulse, indicating that a dis
cation system in which the code converting and error
torted code character has been received. The utilization 70 `detecting circuit of the invention may find application is
equipment includes equipment design to produce a de
shown in FIGURE 4. The telegraph communication sys
sired function in response to the control pulse. For
tem shown is an automatic error correction system. The
example, an automatic repetition request system may be
communication system includes at least two stations 1
placed in operation such that the conversion is ignored
and 2 which are electrically connected together over dif
and the telegraph transmitting terminal station is auto 75 ferent electrical paths 340, 341 for two way communica
3,055,978
21
tion. Code characters are produced by the operation of
a telegraph transmitter 342 at the first station 1 for trans
22
control unit 354 is controlled by a receiver timing unit
359. Signal energy is applied from a frequency stand
mission over a channel A to a transmitter unit 343. Code
ard unit 360 to a frequency correction unit 361 over
characters are also produced by the operation of a sec
lead 362. The receiver unit 348 includes equipment for
ond telegraph transmitter 344 for transmission over a 5 producing a train of control signals of a frequency corre
second channel B to the transmitter unit 343. Each code
sponding to the frequency of the signal elements in
character transmitted over channel A and over channel B
cluded in the multiplex signal received by the receiver
includes tive signal elements arranged according to the
unit 348 over the electrical path 340. The train of
fixed-length, five-unit telegraph code. In addition, start
control signals is applied over lead 363 to the frequency
and other control information is forwarded to the trans 10 correction unit 361. Timing signals produced by the
mitter unit 343 over the respective channels A and B.
receiver timing unit 359 are also applied to the frequency
The five-unit code characters, which may each include,
correction unit 361 over a lead 364. The frequency
for example, signal elements transmitted over the respec
correction unit 361 compares the frequency of the con
tive channels A, B in para-llel form, are received in order
trol signals received over lead 363 with the frequency
by the transmitter unit 343 and are applied, in turn, from
of the timing signals received over lead 364. If the
the transmitter unit 343 to a transmitter control unit 345
over lead 346. The transmitter control unit 345 functions
to convert the tive-unit code characters into seven~unit
code characters. The converted code characters are
control signals are early compared to the timing signals,
the frequency of the signal energy applied from the fre
quency correction unit 361 to the receiver timing unit
359 over lead 365 is adjusted so that the timing signals
thereafter applied from the transmitter control unit 345 20 produced by the operation of the receiver timing unit
359 are advanced. lf the control signals are late, the
mitter unit 343 is operated to transmit the converted code
timing signals are retarded. Timing signals of the proper
_characters appearing on channels A, B over the electrical
frequency and in a given order are applied from the
path 340 to the receiver unit 348 at the second station 2
receiver timing unit ‘359 to the receiver control unit
in multiplex fashion. As the code characters are trans 25 354 over leads represented by lead 366 and to the re
mitted over the electrical path 346, equipment is provided
ceiver unit 348 over leads represented by lead 367.
in the transmitter unit 343 for storing on a continuous
interconnections represented by lead 368 are completed
basis the last three code characters transmitted over chan
between the receiver control unit 354 and the frequency
nel A and the last three code characters transmitted over
correction unit 361. Timing signals produced by the
channel i3.
operation of the receiver control unit 354 are applied
in order to accomplish the transmission of rthe code
over lead 363 to the frequency correction unit 361,
characters over channels A, B, the transmitter unit 343
while timing signals produced by the operation of the
and transmitter control unit 345 must operate in a pre~
frequency correction unit 361 are applied over lead
determined time sequence. Thus, the code characters
368 to the -receiver control unit 354. The receiver unit
are first received in order over the channels A, B by the 35 343 and the receiver control unit 354 are operated in
transmitter control unit 345. The transmitter cont-rol
the proper time sequence in response to the timing signals
unit 345 operates to convert the code characters and to
applied thereto to perform the functions outlined above.
apply the converted code characters back to the trans
While the above description has been directed to the
mitter unit 343. The transmitter unit 343 thereafter
equipment used to complete the transmission of code
operates to transmit the converted code characters in 40 characters »from the ñrst station 1 to the second station
multiplex fashion over the electrical path 340. A trans
Z, the description applies equally well, with one excep
mitter timing unit 349 is provided which is operated in
tion, to the equipment used to complete the transmission
response to signal energy of a predetermined frequency
of code characters from the second station 2 to the first
applied to the transmitter timing unit 349 from a fre
station 1. For ease of description, the corresponding
quency standard unit 35d over lead 351. The trans 45 equipment used to complete the transmission of message
mitter timing unit 349 operates to produce timing signals
signals between the two stations 1 and 2 in the different
back to the transmitter unit 343 over lead 347. The trans
of a predetermined frequency which are applied in a
directions has been identified by the same reference nu~
given order over leads »represented by lead 352 to the
merals, the reference numerals identifying the equipment
transmitter unit 343 and over leads represented by lead
used to complete the transmission of message signals
353 to the transmitter control unit 345. The transmitter 50 from station 2 to station 1 being primed. Code char
unit 343 and transmitter control unit ‘1345 operate in
acters produced by the operation of the telegraph trans
response to the timing signals to perform the functions
mitters 342', 344', as well as necessary control informa
outlined above.
tion, are transmitted over the respective channels A',
The multiplex signal transmitted over the electrical
B' to the transmitter unit 343'. The tive-unit code char~
path 340, which may include, `for example, a radio fre»
acters are converted into seven-unit code characters by
quency transmission system, is received by the receiver
the transmitter control unit li345'. The converted code
unit 348 located at the second station 2. The seven
characters are then transmitted by the operation of the
unit code characters are applied, in turn, from the re
transmitter unit 343' in multiplex fashion over the elec
ceiver unit 348 .to a receiver' control unit 354 over lead
trical path 341, the transmitter unit 343’ including equin
355. The receiver control unit 354, which may be con~ 60 ment for storing on a continuous basis the last three code
structcd according Ito the invention, converts the seven
characters transmitted over channel A’ and the last three
unit code characters into five-unit code characters. As
code characters transmitted over channel B'. The mul
previously described in detail, equipment is included in
tiplex signal is received by the receiver unit 348’ and the
the receiver control unit 354 for counting the number of
seven-unit code characters converted into five-unit code
marking elements in each seven-unit code character re 65 characters by the receiver control unit 354'. The con
ceived. It will be assumed for the moment that all the
verted code characters are then distributed in the proper
code characters are properly received without distortion.
manner over the channels A', B’ to the telegraph printers
The converted, tive-unit code characters are applied from
357', 358', respectively.
the receiver control unit 354 back to the receiver unit
Up to this point. it has been assumed that the code
348 over lead 356. The receiver unit 348 functions to 70 characters in the respective multiplex signals transmitted
distribute the code characters transmitted over channel
`over the electrical paths 3401. 341 are received bv the
A to a first telegraph printer 357 and the code char
receiver units 348, 348', respectively. without distortion.
acters transmitted over channel B to a second telegraph
The operation of the stations 1. 2 without the provision
printer 358.
for error correction to be described would be similar to
The timing of the receiver unit 348 and of the receiver 75 that which would occur in any simple two Way com
3,055,978
munication system. If one of the code characters trans
mitted over channel A and received by the receiver unit
348 at the second station 2 is detected by the receiver
control unit 354 as -a distorted character (a code char
acter including more than or less than three marking ele
ments), a control signal is applied f-rorn the receiver con
trol unit 354 to the receiver unit 348 over lead 356 in
the manner outlined above. The receiver unit 348 goes
the transmission of the last three code characters trans
mitted over channel B. When the code character pre
viously received distorted is received correctly, the normal
transmission of code characters from the telegraph trans
mitter
`and from
344the
.to telegraph
the telegraph
transmitter
printer 34
358’ to
over
thechannel
telegraph
printer 358’ over channel B’ resumes. The correction
of the code character transmitted over channel B and
received distorted by the received unit 348 does not affect
into cycling in response to the control signal, halting the
further distribution of the code characters transmitted l O either the transmission of code characters from the tele
graph transmitter 342 to the telegraph printer 357 over
over channel A to the telegraph printer ‘357. At the
same time a control signal is applied from the receiver
unit 348 to the transmitter unit 343' over lead 369. The
transmitter unit 343' interrupts the ltransmission of the
code characters transmitted over channel A’ by the op
channel A or the transmission of the code characters
from the telegraph transmitter 342’ to the telegraph
printer 357’ over channel A’. The correction of a code
15 character received distorted over one of the channels A
eration of the telegraph transmitter 342’ and proceeds
to transmit a repetition request signal or Signal l plus
the last three code characters transmitted over channel
A’ and stored by equipment in the transmitter unit 343’.
or B proceeds independently of the correction of a code
character received distorted over the other channel. The
control unit 354', and a control signal is applied from
the circuit operations outlined above.
The operation of the communication system in the
correction of a code character received distorted over
channel A and of a code character received distorted
The repetition request signal is detected by the receiver 20 over channel B may proceed at the same time following
the receiver control unit 354’ to the receiver unit 345’
over lead 356'. The receiver unit 348’ goes into cycling
and prevents the distribution of the repeated code char
acters transmitted over channel A’ to the telegraph printer
357’. At the same time a control signal is applied from
the receiver unit 348’ to the transmitter unit 343 over
lead 370. The transmitter unit 343 operates in response
to the control signal to interrupt the transmission of the
reverse direction to correct code characters received dis
torted by the receiver unit 348’ over channels A’ or B’
is exactly the same as when code characters are received
distorted by the receiver unit 348 over channels A or
B. lf a code character is received distorted over channel
A' or B', the transmitter unit 343’ is operated to repeat
the code character until it is correctly received by the
code characters produced by the telegraph transmitter 30 receiver unit 348’.
342 for transmission over channel A. The transmitter
An automatic error correction system of the type de
343 unit proceeds to transmit a repetition request signal
scribed requires that one station in the system be the
or Signal I plus the last three code characters transmitted
master, while a second station in the system be the slave.
over channel A which were stored by equipment in the
As shown in FIGURE 4, the ñrst station 1 is the master
transmitter unit `343. The loop time delay of the error 35 station in that the transmitter timing unit 349 is op
correction system is such that the code character received
erated in response to signal energy applied thereto from
distorted by the receiver unit 348 is stored in the trans
the frequency standard unit 35i@` over lead 351. The sec
mitter unit 343. If the code character previously re
ond station 2 is the slave station in that the transmitter
ceived distorted is now received correctly by the receiver
timing unit 349’ is operated in response to signal energy
unit 348, the receiver unit 348 goes out of cycling. The
applied thereto from the receiving timing unit 359 over
communication system resumes its normal condition of
operation in which code characters are transmitted from
the telegraph transmitter 342 to the telegraph printer 357
lead 373.
The stations 1, 2 in the automatic error cor
rection system must be arranged for synchronous opera
tion to insure the proper operation of the correction
over channel A and in which code characters are trans
loops. vlf the transmitting timing units 349, 349' were
mitted from the telegraph transmitter 342’ to the tele
both operated in response to signal energy applied there
graph printer 357’ over channel A’. If, however, the
to from a frequency standard unit, a phase di'tference
code character is again received distorted, the above se
would exist which would vary by the amount that the
quence of operations will continue until the code char
two frequency standard units differed in frequency. By
acter is received correctly by the receiver unit' 34‘8.
applying the signal energy from the receiving timing unit
The correction of the code character received distorted 50 359 to the transmitter timing unit 349', the operation
by the receiver unit 348 over channel A does not aítect
of the receiver timing unit 359‘ being controlled by the
the transmission of the code characters from the tele
frequency correction unit 361, a synchronously operated
»graph transmitter 344 to the telegraph printer 358 over
system is provided.
channel B and from the telegraph transmitter 344' to
The code converting and error detecting circuit of the
the telegraph printer 358’ over channel B'. The trans 55 invention by using magnetic cores in the manner de
mission of the code characters over the channels B, B’
scribed to perform functions previously performed by
proceeds in the normal manner. If a code character
other equipment is more compact and simpler in opera
transmitted over channel B should be received distorted
tion than circuits known heretofore. Because of these
by the receiver unit 348, the receiver unit 348 goes into
features, the circuit of the invention is valuable and
cycling. The distorted code character is not distributed
readily adaptable for use in performing code conversion
to the telegraph printer 358, and a control signal is ap
and error detection in systems, for example. of the type
plied -from the receiver unit 348 to the transmitter unit
described in connection with FlGURE 4. While a single
343’ over lead’371. The transmitter unit 343’ interrupts
diplex or two channel Ámultiplex telegraph communica
the transmission of the code characters transmitted over
tion system is shown in FIGURE 4, the error correction
channel B’ by the telegraph transmitter 344’ and proceeds 65 system described above, including the circuit of the in
to transmit over channel B' a repetition request signal
vention, may be incorporated in other multiplex tele
plus the last lthree code characters transmitted over chan
graph communication systems known in the art.
nel B', which were stored by equipment in the transmit
What `is claimed is:
ter unit 343'. The receiver unit 348’ prevents the dis
l. In combination7 a source of code characters each
tribution of the repeated code characters to the telegraph
including a ñxed number of signal elements arranged in a
printer 358', -and a control signal'is applied from the re
predetermined ratio of signal elements of one nature to
ceiver unit 348’ to the‘transmitter unit 343 over ’lead
signal elements of another nature, said signal elements
372.` The transmitter unit 343 interrupts the transmission
appearing in a diiferent order in each of said code char
of the code characters transmitted over channel B by
acters, a first storage device, a second storage device
the telegraph transmitter 344 and proceeds to repeat
separate from said first storage device, a distributing cir
3,055,978
as@
cuit coupled between said source and both of said devices
and arranged upon the reception by said distributing cir
cuit of a received code char: cter to establish an electrical
of appearance of said spacing elements, an error detecting
circuit coupled to said source and arranged upon the re
condition in said first device according to the order of
ception by said error detecting circuit of said received
code character to count the number of said marking ele
appearance of said signal elements of one nature and an
ments included therein, and an output circuit including a
electrical condition in said second device according to the
order of appearance of said signal elements of another
nature, and means including a code converter coupled
to both of said devices and responsive to the electrical
conditions established in said devices.
2. in combination, a source of code characters each
including -a predetermined ratio of signal elements of one
nature to signal elements of another nature, said signal
elements appearing in a different order in each of said
code characters, a distributing circuit coupled to said
source, an error detecting circuit coupled to said source,
code converter coupled to both of said devices and to
said error detecting circuit, said output circuit being re
sponsive to the electrical conditions established in said
devices and to the operation of said error detecting circuit.
5. ln combination, a source of code characters each
inciuding a predetermined ratio of signal elements of
one nature to signal elements of another nature, said
signal elements appearing in a diii’erent order in each of
said code characters, first and second shift registers each
including a chain of magnetic cores capable of assuming
one of two states, a distributing circuit including a plu
rality of magnetic cores coupled between said source and
both of said registers, means for operating said circuit
upon the reception of a code character by said circuit to
operating said distributing circuit upon the reception by 20 cause certain of the magnetic cores in said first register
said distributing circuit of a received code character to
to assume one of said states according to the order of
a first storage device coupled to said distributing circuit,
a second storage device separate from said ñrst storage
device and coupled to said distributing circuit, means for
establish an electrical condition in said first device ac
cording to the order of appearance of said signal elements
of one nature and an electrical condition in said second
device according to the order of appearance of said signal
elements of another nature, means included in said error
detecting circuit responsive to the reception by said error
detecting circuit of said received code character to count
appearance of said signal elements of one nature and
certain of the magnetic cores in said second register to
assume said one state according to the order of appear
ance of said signal elements of another nature, and means
coupled to both of said registers and responsive to the
electrical conditions established in said registers.
6. In combination, a source of code characters each
the number of said signal elements of one nature included
including a predetermined ratio of signal elements of one
therein, and an output circuit coupled to both of said de 30 nature to signal elements of another nature, said signal
vices and to said error detecting circuit, said output cir
cuit being responsive to the electrical conditions estab
lished in said devices and to the operation of said error
detecting circuit.
3. in combination, a source of code characters each
including a predetermined ratio of signal elements of
one nature to signal elements of another nature, said sig«
nal elements appearing in a diiîerent order in each of
said code characters, a distributing circuit coupled to said
source, an error detecting circuit coupled to said source,
a ñrst storage device coupled to said distributing circuit,
a second storage device separate from said first storage
device and coupled to said distributing circuit, a second
source of signal energy in the form of a train of timing
pulses coupled to said distributing circuit and to said
error detecting circuit, means included in said distributing
circuit responsive to said timing pulses upon the reception
by said distributing circuit of a received code character
elements appearing in a different order in each of said
:code characters, first and second shift registers each in
cluding a chain of magnetic cores, a distributing circuit
coupled between said source and both of said registers,
means for operating said distributing circuit upon the
reception by said distributing circuit of a received code
character to establish an electrical condition in said first
register according to the order of appearance of said sig
nal elements of one nature and an electrical condition in
said second register according to the order of appear
ance of said signal elements of another nature, a third
shift register including a chain of magnetic cores coupled
to said source, means for operating said third register
upon the reception by said third register of said re
ceived code character to count the number of said signal
elements of one nature included therein, and an output
circuit coupled to said iirst, second and third registers,
said output circuit being responsive to the electrical con
to establish an electrical condition in said first device ac
ditions established in said first and second registers and
cording to the order of appearance of said signal elements 50 to the operation of said third register.
of one nature and an electrical condition in said second
7. A combination as claimed in claim 6 and wherein
device according to the order of appearance of said signal
said distributing circuit includes a plurality of magnetic
cores, said plurality of magnetic cores being operated
upon the reception by said distributing circuit of each of
elements of another nature, means included in said error
detecting circuit responsive to said timing pulses upon the
reception by said error detecting circuit of said received
code character to count the number of said signal ele
said signal elements of one nature to apply a control
ments of one nature included therein, and means includ
pulse to said first register and upon the reception by said
distributing circuit of each of said signal elements of
ing a code converter coupled to both of said devices and
to said error detecting circuit, said last-mentioned means
register.
being responsive to the electrical conditions established 60
8. In combination, a source of code characters each
including a predetermined ratio of signal elements of one
in said devices and to the operation of said error detecting
circuit.
4. In combination, a source of code characters each
another nature to apply a control pulse to said second
nature to signal elements of another nature, said signal
elements appearing in a different order in each of said
including a combination of seven serially appearing signal
code characters, ñrst and second shift registers each in
elements arranged in a ratio of three marking elements 65 cluding a chain of magnetic cores, a distributing circuit
including a plurality of magnetic cores coupled between
to four spacing elements, the »marking and spacing ele
ments appearing in a different order in each of said code
characters, a first storage device, a second storage device
said source and both of said registers, a second source
of signal energy in the form of timing pulses, driving
means coupled between said second source and said dis
separate from said íirst `storage device, a `distributing cir
cuit coupled between said source and both of said devices 70 tributing circuit, said distributing circuit arranged to be
operated by said driving means in response to said timing
and arranged upon the reception by said distributing cir
cuit of a received code character to establish an electrical
pulses upon the reception of la received code character by
condition in said iirst `device according to the order of
appearance of said marking elements and an electrical
said distributing circuit to establish an electrical condi
tion in said first register according to the order of ap
Y condition in said second device according to the order 75 pearance of said signal elements of one nature and an
3,055,978
27
255
electrical condition in said second register according to
output circuit upon the counting by said register of a
number other than a predetermined number of said mark
the order of appearance of said signal elements of an
ing elements in said received code character.
other nature, a third shift register including a chain of
magnetic cores coupled to said iirst source and to said
14. In combination, a source of code characters each
driving means and arranged to be operated by said driv Lu including a fixed number of signal elements arranged in
a predetermined ratio of signal elements of one nature to
ing means in response to said timing pulses upon the re
ception of said received code character by said third
register to count the number of said signal elements of
one nature included therein, and means including a code
converter coupled to said iirst, second and third registers,
said last-mentioned means being responsive to the elec
trical conditions established in the tirst and second regis
ters and to the operation of said third register.
9. ln combination, a source of code characters each
including seven signal elements arranged in a ratio of
three marking elements to four spacing elements, said
signal elements of another nature, said signal elements
appearing in »a different order in each of said code charac
ters, iirst and second storage devices, a distributing circuit
-coupled between said source and both of said devices and
arranged upon the reception by said distributing circuit
of a received code character to establish an electrical con
dition in said iirst device according to the order of ap
pearance of said signal elements of one nature and an
electrical condition in said second device according to
the order of appearance of said signal elements of an
other nature, a shift register including `a chain of mag
signal elements appearing in a different order in each of
said code characters, first and second shift registers each
netic cores coupled to said source, an output circuit cou
including a chain of magnetic cores, a distributing cir
pled to and responsive to the operation of both of said
cuit including a plurality of magnetic cores coupled be 20 devices, a single magnetic ycore coupled between said
tween said source and »both of said registers, a second
register and said output circuit, timing means connected
source of signal energy in the form of timing pulses, driv
ing means coupled between said second source and said
ception by said register of said received code character
distributing circuit, said distributing circuit arranged to
to said register for operating said register upon the re
to count the number of said signal elements of one nature
be operated by said driving means in response to said tim
included therein, and means to connect said single mag
ing pulses upon the reception of a received code char
netic core to said timing means for operating said single
acter by said distributing circuit to establish an elec
magnetic core to apply a control signal to said output
trical condition in said first register according to the order
circuit upon the counting by said register of a number
of appearance of said marking elements and an electrical
other than a predetermined number of said signal ele
condition in said second register according to the order of 30 ments of one nature in said received code character.
appearance of said spacing elements, a third shift register
15. In combination, a source of code characters each
including a chain of magnetic cores coupled to said iirst
including a predetermined ratio of signal elements of
source and to said driving means and arranged to be
one nature to signal elements of `another nature, said
operated by said driving means in response to said
signal elements appearing in a different order in each of
timing pulses upon the reception of said received code
said code characters, first and second shift registers each
character by said third register to count the number of
including a chain of magnetic cores, a distributing circuit
marking elements included therein, and an output cir
coupled @between `said source and both of said registers,
cuit including a code converter coupled to said ñrst, sec
timing means connected to said distributing circuit for
ond and third registers, said output circuit being respon~
operating said distributing circuit upon the reception by
sive to the electrical conditions established in said first 40 said distributing circuit of a received code character to
and second registers and to the operation of said third
establish an electrical condition in said first register ac
register.
cording to the order of appearance of said signal elements
`it). ln combination, a source of code characters each
including a predetermined ratio of signal elements of one
nature to signal elements of another nature, a shift
register including a chain of magnetic cores coupled to
said source, an output circuit, a single magnetic core
coupled between said register and said output circuit,
timing means connected to said register for operating said
register upon the reception by said register of a received
code character to count the number of said signal ele
ments of one nature included therein, said single mag
netic core being responsive to the operation of said regis
ter to apply a control signal to said output circuit upon
the counting by said register of a number other than a,
predetermined number of said signal elements of one
nature in said received code character.
11. A combination as claimed in claim 10 and wherein
said timing means includes a source of signal energy in
the form of timing pulses.
l2. A combination as claimed in claim 10 and wherein
said output circuit includes a second shift register in
cluding a chain of magnetic cores and having an out
of one nature and an electrical condition in said second
register according to the order of appearance of said
signal elements yof another nature, a third shift register
including a chain of magnetic cores coupled to said source,
an output circuit coupled to and responsive to the opera~
tion of said first and second registers, a single magnetic
core coupled Ibetween said third register and said output
circuit, means to connect said third register to said timing
means for operating said third register upon the reception
by said third register of said received code character to
count the number of said signal elements of one nature
included therein, and means to connect said single mag
netic core to said timing means for operating said single
magnetic core to apply a control signal to said output
circuit upon the counting by said third register of a num
ber other than a predetermined number of said signal
elements of one nature in said received code character.
16. A combination as claimed in claim 15 and wherein
said timing means includes a source of signal energy in
the form of timing pulses, said output circuit including
a shift register comprising a chain of magnetic cores
Iand having an output terminal.
13. ln combination, a source of code characters each Ob C31
17. In combination, a source of code characters each
including seven signal elements arranged in a ratio of three
including seven signal elements arranged in a predeter
marking elements to four spacing elements, a shift regis
mined ratio of three marking elements to four spacing
ter including a vchain of magnetic cores coupled to said
elements, said signal elements appearing in a diíferent
source, an output circuit, a single magnetic core coupled
order in each of said code characters, first and second
between said register and said output circuit, timing means 70 shift registers each including a chain of magnetic cores,
connected to said register for operating said register upon
a `distributing circuit coupled between said source and
the reception by said register of a received code character
both of said registers, timing means connected »to said
to count the number of said marking elements included
distributing circuit for operating said distributing circuit
therein, said single magnetic core being responsive to the
upon the reception lby said distributing circuit of a
operation of said register to apply a control signal to said 75 received code character to establish an electrical con
put terminal.
29
3,055,978
30
dition in said first register according to the order of
distributing circuit for operating said distributing cir
appearance of ysaid marking elements and an electrical
cuit upon the reception by said distributing circuit of
condition in said second register according to the order of
a received code character to establish an electrical con~
appearance of said spacing elements, a third shift register
dition in said first register according to the order of ap
including a chain of magnetic cores coupled to said source,
pearance of said signal elements of one nature and an elec
an output circuit coupled to and responsive to the opera
trical condition in said second register 4according to the
tion of said first and second register, a single magnetic
order of appearance of said signal elements of another
core coupled between said third register and said output
nature, a third shift register including a chain of mag
circuit, means to connect said third register to said timing
netic cores coupled to said source, means to connect said
means for operating said third register upon the recep 10 third register to said timing means for operating said third
tion by said third register of said received code character
register upon the reception by said third register of said
to count the number of said marking elements included
received code character to count the number of said sig
therein, and means to connect said single magnetic core
nal elements of one nature included therein, an output
to said timing means for operating said single magnetic
circuit, 'a single magnetic core coupled between said third
core to apply a control signal to said output circuit upon 15
register and said output circuit, means to connect said
the counting by said third register of a number other
single magnetic core to said timing means for operating
than a predetermined number of said marking elements
said single magnetic core to apply a control signal to said
in said received code character.
18. In combination, ra source of code characters in a
output circuit upon the counting by said third register of
a number other than a predetermined number of said
telegraph code each including a fixed number of signal 20 signal elements of one nature in said received code char~
elements arranged in a predetermined ratio of signal
acter, a code converter coupled between both of said
elements of one nature to signal elements of another
first and second registers and said output circuit respon
nature, said signal elements appearing in la difîerent order
sive to said electrical conditions to produce a conversion
in each of said code characters, a first storage device, a
of said received code character, and means for applying
second storage device separate from said first storage 25 said
conversion from said code converter to said output
device, `a distributing circuit coupled between said source
circuit.
yand both of said devices and arranged upon the reception
20. A combination as claimed in claim 19 and where
by said distributing circuit of a received code character
Iin said distributing circuit includes a plurality of mag
to establish an electrical condition in said first device ac
netic cores, said output circu-it including a shift register
cording to the order of appearance of said signal elements 30 comprising a chain of magnetic cores and having an out
of one nature and >an electrical condition in said second
put terminal.
device yaccording to the order of appearance of said sig
2l. A code conversion circuit comprising, in combina
nal elements of `another nature, an output circuit, an error
tion, input means adapted to receive code characters each
detecting circuit coupled to said source »arranged upon
including a fixed number of signal elements arranged in
the reception by said error detecting circuit of said re
an order of signal elements of one nature and signal ele
ceived code character to count the number of said sig
ments of lanother nature, a first storage device, a second
nal elements of one nature included therein and to apply
storage device separate from said first storage device, a
a control signal to said output circuit upon the counting
distributing circuit coupled between said input means
by said error detecting circuit of a number other than
and both of said devices and arranged upon the reception
`a predetermined number of said signal elements of one 40 by said distributing circuit of a received code character
nature in said received code character, a code converter
coupled between both of said devices and said output
circuit responsive to said electrical conditions established
to establish `an electrical condition in said first device ac
cording to the order of appearance of said signal elements
of one nature and an electrical condition in said second
in said first and second devices to produce a conversion
device according to the order of appearance of said sig
of said received code character, and means for applying 45 nal elements of another nature, an output circuit, a code
said conversion from said code converter to said output
converting circuit coupled to both of said devices re
circuit.
sponsive to said electrical conditions to produce a con
19. In combination, a source of code characters in
version of said received code character, and means to
a telegraph code each including a predetermined ratio
Iapply said conversion from said code converting circuit
of signal elements of one nature to signal elements of 50 to said output circuit.
another nature, said signal elements appearing in a dif
ferent order in each of said code characters, first and
second shift registers each including a chain of magnetic
cores, -a distributing circuit coupled between said source
and both oí‘ said registers, timing means connected to said 55
References Cited in the file of this patent
UNITED STATES PATENTS
2,724,739
Harris ______________ __ Nov. 22, 1955
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