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Nay. 5,1946. I
J‘. A. RANKIN
2,410,523
PHASE-RESPONSIVE SYSTEM
Filed April 21, 1945
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INVENTOR.
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JOHN A. RANKINv I
'
‘ATTORNEYS
Patented Nov. 5, 1946
UNlTED STATES‘ PATENT orrice
2,410,523
PHASE-RESPONSIVE SYSTEM
John A. Rankin, Park Ridge, 111., assignor to Bel
mont Radio Corporation, Chicago, 111., a corpo
ration of Illinois
Application April 21, 1945, Serial No. 589,471
10 Claims.
(01. 250—-3.6)
1
2
This invention relates to phase-responsive sys
tems and, while it is of general application, it is
particularly adapted for the synchronization of
scanning oscillators of television receivers from
ing while its scope will be pointed out in the ap
pended claims.
Referring now to the drawing, Fig. l is a circuit
diagram of a phase-responsive system embodying
the invention as applied to the synchronization
received synchronizing pulses.
It has been the general practice to synchronize
a scanning oscillator of a television receiver by
triggering it directly with the received synchro
nizing pulses after separation from the composite
television signal and after separation of the line
synchronizing pulses from the ?eld-synchroniz
ing pulses, While ideally this arrangement is
effective to initiate each scanning line and each
scanning ?eld at precisely the correct point in
the scanning cycles, it has been found that, in
practice, it is difficult to prevent incorrect trig
of a periodic wave generator from an input peri
odic wave; while Figs. 2a and 2b are graphs of‘
certain operating characteristics of the system
of Fig. 1 to aid in an explanation of the inven
tion.
Referring now to the drawing, there is repre
sented a phase-responsive system embodying the
invention for developing an electrical effect Vary
ing with relative phase of two periodic electri
cal waves, speci?cally for synchronizing a peri
- odic wave generator H3 with an input periodic
gering of the scanning oscillators by random
wave of an integrally related frequency applied
noise pulses in the received signal, particularly
to input terminals l I. By the term‘ “integrally re
if such pulses occur approximately at the time a
lated frequency” is meant that the ratio of the
synchronizing pulse is due. The result of such 20 frequency of the input wave to. that of the gen
spurious triggering of the scanning oscillators is
erated wave or the ratio of the frequency of the
line tearing and jumping in the case of the line
generated wave to that of the input wave is an
scanning oscillator and, in case of the ?eld-scan
integer; that is, the generated wave is a har
ning oscillator, failure to interlace properly or
monic or a subharmonic of the input wave while
complete loss of the picture. The present inven 25 the input wave and the generated wave may be
tion is directed to a phase-responsive system
which, while of general application, is particularly
suitable for maintaining a constant average phase
relation between the received synchronizing
pulses of a television signal and the scanning
waves developed by the scanning oscillators of
a television receiver.
It is an object of the invention, therefore, to
provide a new and improved phase-responsive
system by means of which the average phase be
tween two periodic electric waves may be main
tained constant.
,
In accordance with the invention, a phase-re
sponsive system for developing an electrical ef
fect varying with the relative phase of two peri
odic electrical waves comprises means for com
bining the two waves with a given polarity, means
of any desired wave shapes, preferably one of the
waves, for example the input wave, is a rela
tively broad pulse wave such as a half-sine wave,
as represented adjacent the terminals ll, while
the other wave developed by the generator It is
a relatively narrow pulse wave, as indicated at
the output connections of the generator l0 de
scribed hereinafter, For example, the generator
I0 may be of the conventional blocking-oscillator
type comprising a vacuum tube 12 supplied with
a space current from a suitable source +B
through a transformer primary winding l3. The
grid circuit of the tube l2 includes a transformer
secondary winding Hi coupled to the winding i3
40 and a time-constant circuit including a con
denser l5 effectively in parallel with a resistor It
and a resistor 16a in series. The transformer
for individually deriving from the waves two
also includes a tertiary winding ll having its
midpoint grounded and coupled to the primary
bining the opposite polarity waves. The system 45 winding l3 and an output winding 9 from which
also includes means for relatively time-displac
may be derived the narrow-pulse wave of oppo
ing at least one of the waves before combining,
site polarity.
means for individually rectifying the two com
The system also includes means for combining
waves of opposite polarity, and means for com
bined waves, and an output circuit connected to
the input wave at the terminals H with a wave
derive the di?erence in the outputs of the two 50 derived from the generator It with the same given
rectifying means.
polarity, for example with a positive polarity,
For a better understanding of the invention,
and with the pulses thereof at least partially co
together with other and further objects thereof,
inciding in time. This means includes a vacuum
reference is had to the following description
tube repeater or ampli?er I 8 having a signal
taken in connection with the accompanying draw 55 input grid to which the input signal at the ter-'
2,410,523
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'minals H is applied and an anode load resistor
is and a cathode load resistor 20. This means
also includes a combining or modulating tube
2| having two signal-input grid electrodes indi
vidually connected to the load resistor l9 and to
in a conventional manner to develop in its out
put circuit a pulse voltage wave comprising a
the terminal I'Ia of winding I‘! and provided
be utilized in any one of a number of ways well
known to the art; for example in a television
receiver this pulse wave may be used to syn
chronize a scanning-wave generator. This wave
series of brief pulses of approximately half-sine
wave shape separated by intervals determined by
the time constant circuit l5, l6, 16a. This may
with an anode load resistor 22.
The system also includes means for individually
deriving from the two waves two other Waves of
opposite polarity.
This means comprises the 10 comprising short duration pulses, such as the
pulses b, may be derived from the output wind
cathode load resistor 2i! of the tube l8 across
which is developed an. input-signal pulse wave of
polarity opposite to that developed across the
ing 9.
+3
posite or lagging sloping side of the input pulses
“
The circuit constants are so proportioned that,
anode load resistor l9, as indicated by the adja
during normal operation, the pulses a and b at
cent pulse in Fig. 1, and the other half of the 15 least partially coincide in time. As illustrated the
transformer tertiary winding I‘! which supplies a
pulse b falls on the leading sloping side of the
generated wave of opposite polarity from the ter
input pulse a._ In this ?gure the voltage 61 rep
minal llb.
resents the peak-recti?ed voltage developed by
There is also provided a second vacuum tube
the recti?er 3B and appearing across its load re
combining ampli?er or modulator 23 having two
sistor 32.
signal-input grid electrodes one of which is con
Similarly in Fig. 2b are represented the input
nected to the cathode load resistor 20 to receive
pulses <11 of opposite polarity as combined with
the input wave of opposite polarity and the other
the generated pulses in of opposite polarity. The
of which is connected to the terminal lib to
pulses in are delayed by the network 25 by an
receive the generated wave of opposite polarity.
amount such that they are still at least partially
The tube 23 is provided with an anode load re
coincident with the input pulses m but preferably
sistor 24 while the tubes l8, 2! and 23 are sup
by an amount less than the duration of one of
plied with space current from a suitable source
such pulses so that the pulses in fall on the op~
.
. ‘The system also includes means for relatively 30 or.
In this ?gure the Voltage 62 represents the
time-displacing at least one of the waves before
peak-recti?ed output of the recti?er 26 appearing
combining and, by way of example, there is illus
trated a time-delay network 25 interposed be
tween the terminal Ill) and the signal grid of
across its load resistor 28. The difference be
tween the two recti?ed voltages e2 and er de
veloped by the recti?ers 26 and 30 is derived by
the combining tube 23 and effective to delay the 35 means of the control circuit 40 and the isolating
resistors 3d, 35 which develop a unidirectional
narrow pulse wave of opposite polarity devel
bias voltage varying with the difference in the
oped by the generator Hl.
V
_
V
outputs of the two recti?ers 26 and 38 and, by way
Included in the system are means for indi
of the ?lter circuit 36,v apply such difference volt
vidually peak-rectifying the two combined waves.
This means comprising a diode recti?er 26 cou 40 age to the control electrode of the blocking oscil
lator tube l2 to control the frequency thereof in
pled across the load resistor 24 of the combin
a well-known manner.
ing tube 23 through a coupling condenser 21 and
From the foregoing it will be clear that, should
provided with a shunt load resistor 28. Simi
the frequency of the blocking oscillator 10 tend
larly, the combined wave developed across the
load resistor 22 of the combining tube 2| is ap 4. to fall below that of the input synchronizing wave
at the terminals H, the pulses b and b1 gen
plied through a coupling condenser 3| to a diode
erated thereby will tend to lag the input pulses a
recti?er 30 connected with reverse polarity and
and (11, respectively. This is effective to increase
provided with shunt load resistor 32.
the positive peak recti?ed voltage 62 and to de
Connected to the two peak recti?ers described
is an output circuit 40 for deriving the differ 50 crease the negative peak recti?ed voltage 24,
thereby decreasing the normal negative bias on
ence in the outputs of the two peak recti?ers and
the grid of the tube 12 to decrease the period of
comprising means responsiveto such difference
the generator 10, that is to increase its frequency,
for controlling the frequency of the generator
until a condition of equilibrium is restored. Ob;
Ill. The circuit 40 includes isolating resistors 34
viously, in case the frequency of the generator l0
and 35 connected to the load resistors 28 and
tends to rise above that of the input wave at the
32, respectively, of the two recti?ers and a ?lter
terminals H, the reversed process takes place.
circuit 36 comprising a series resistor 31 and
While theinvention has been described as ap
shunt condensers 38 and 39 and is connected to
plied to a frequency divider, that is an arrange
the junction between time-constant resistors l6
and Ilia in the grid circuit of the blocking-oscil 60 ment for generating a pulse wave which is a sub
harmonic of the input wave, it will be apparent
lator generator E0.
that it is equally applicable to a system having
The operation of the phase-responsive system
any other integral frequency relation between the
of the invention may be best understood by ref
erence to Figs.w2a and 2b, which illustrate the . input wave and that developed by the generator
invention as applied to the synchronization of 65 In. It ‘is only necessary that the pulses a and b,
and a1 and b1 coincide in time, which necessarily
the generator [0 at the fourth subharmonic of
follows from the integral frequency relationship.
the input wave, that is, with the system oper
In the case of frequency multiplication, a plu
ating as a frequency divider. In Fig. 2a the pulses
rality of pulses b and b1 will fall between each
a represent the input wave of positive polarity
developed across the load resistor l9 and applied 70 adjacent pair of pulses a and ‘a1, respectively,
while in the case in which the frequency of the
to an input grid of the combining tube 2!. The
input wave is the same as that generated by the
pulses 17 represent the pulses derived from the
blocking oscillator 10, one of the pulses b or In
blocking oscillator 10 supplied from the terminal
will fall on each of thevpulses a or an, respec
Ha, to the other signal input grid of the com
tively. In the case of frequency multiplication
bining tube 2|. The blocking oscillator operates
75
acids-2s
kg
or- frequency division the average voltaigesbuilt
up on condensers 2T and‘S'li'by the peak recti?ers ,
26. and 301, respectively, :act. as biases on therecti
?ers andv prevent their‘ response to. eithertheaine
put wave or the generated-wave alone and limit
their response to the combined input. and gener—
ated Wave. It. will further be apparent that: any
of the four waves utilizedto develop the control
6
coinciding; in time, means for individually deriv-v
ingfromsaidjwaves two waves of opposite polar
ity, means} for‘ combining; said opposite-polarity
waves, means for relatively time-displacing. at
least one of said waves before combining‘ byan
amount such that the pulses thereof‘ are still
at least partially coincident with’ those of the
wave with which it is combined, meansv for indi
voltage may be advanced or'retardecl with respect
viduallyi rectifying said two combined waves, and
to the others to.v produce. the desired ultimate rela 10 an output’ circuitconnected to derive the di?er
tive time displacement anduthat either the-input
ence in the outputs of said rectifying means.
waves or-the generated waves‘ of opposite polari
'3. A’ phase-responsive. system for developing
ties may both be shifted with respect ,tothe other
an electrical e?‘ect varying with the; relative
in orderto provide a differentaverage phase re-,
. phase of two periodic electrical pulse waves ‘of "
lation between the input Waves andthe. generated
integrally related frequencies, one wave consist
ing of relatively broad pulses and; the other of
An important advantage of the phase-respon
relatively narrow pulses, comprising, means for
sive system described resides in the, fact that, it
combining the two waves with a given polarity
waves.
,
I
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is, substantially completely unresponsive toes-puri
and with the pulses thereof at least partially
ous noise pulses which may be present in the 20 coinciding inv time, means for individually deriv
pulse Wave a appearing at the input circuit 1 I.
ing from said waves two waves of opposite polar
This characteristic can be seen by reference to
ity, means for combining said opposite-polarity
Figs. 2a and 2b in which there are represented
waves, means for relatively time-displacing said
noise pulses n and- m appearing on the pulse
narrow-pulse waves of opposite polarities. before
waves- a and d1 of opposite polarity and, impressed 25 combining by an amount less than the duration
upon the peaked recti?ers 25. and 3%], respectively.
of one of said- broad pulses, means for individue
Due to the fact that these two noise pulses n
ally rectifying said two combined waves, and an
and. m are of the same phase and of opposite
output circuit connected to derive the difference
polarity, their effects on the recti?eeloutputs of
in the outputs of said rectifying means.
therecti?ers 2B and 30v are equal and opposite 30
4. A phase-responsive system for developing
so that. no net noise component is impressedv upon
an» electrical effect varying with’ the relative
the control circuit at. rlFhis is true for all. con: ‘ phase of two; periodicv electrical. pulse waves : of
dition's, except in the case of av noise pulse which,
integrally related frequencies comprising, means
coincides in time with a portion of one of the de—
for combining the two waves with» a given polar
rived pulses b or bi. By making the pulsesb as. , ity
and with the pulses thereof at least partially
narrow as possible, the chance of a. noisepulse
coinciding in time, means for individually derive
n coinciding With a pulse b is minimized. How;
ing from said waves two-waves of opposite polar- '
ever, even in‘this case the only e?ect of the noise
ity,
means for combining said opposite-polarity
pulses is that due to their average energy content,
waves,
means for relatively time-displacing at
which ordinarily is inappreciable. Thus, it is seen 4:0
least one of said waves before combining, means
that in the arrangement described the blocking
oscillator I0 is not excited directly by the input
synchronizing pulses at the terminals H and thus
for individually peak rectifying said two com
bined waves, and an output circuit connected
to derive the difference in the outputs of said
is completely shielded from any random or spuri
rectifying means.
ous noise pulses appearing at the input termi 45
5. A phase-responsive system for» synchroniz
nals. The only effect of such spurious pulses on
ing
a periodic-wave generator with an input
the operation of the system is that due to their
periodic wave of an integrally related frequency
average energy content which, as explained above,
comprising, means for combining the input wave
is inappreciable.
with
a wave derived from the generator with a
While there has been described what is at pres
ent considered to be the preferred embodiment 50 given polarity, means for individually deriving
from said waves two waves of opposite polarity,
of the invention, it will be apparent to those
means
for combining said opposite-polarity
skilled in the art that various changes and mod
waves, means for relatively time-displacing at
i?cations may be made therein without depart
least one of said waves before combining, means
ing from the spirit or scope of the invention.
What is claimed as new is:
1. A phase-responsive system for developing
an electrical e?ect varying with the relative
' phase of two periodic electrical waves compris
ing, means for combining the two waves with
for individually rectifying said two combined
waves, and means responsive to the difference
in the outputs of said rectifying means for con
trolling the frequency of said generator.
6. A phase-responsive system for synchronizing
a periodic-wave generator with an input periodic
a given polarity, means for individually deriving 60 wave of an integrally related frequency com
from said waves two waves of opposite polarity,
prising, means for combining the input wave with
means for combining said opposite-polarity
a wave derived from the generator with a given
waves, means for relatively time-displacing at
polarity, means for individually deriving from
least one of said waves before combining, means 65 said waves two waves of opposite polarity, means
for individually rectifying said two combined
for combining said opposite-polarity ‘waves,
waves, and an output circuit connected to derive
means for relativelytime-displacing at least one
the difference in the outputs of said rectifying
of said waves before combining, means for indi~
means.
vidually rectifying said two combined waves, and '
2. A phase-responsive system for developing
a circuit for developing a unidirectional bias
an electrical effect varying with the relative
voltage-varying with the dilference in the out
phase of two periodic electrical pulse waves of
puts of said rectifying means for application to
integrally related frequencies comprising, means
said generator to control the frequency thereof.
for combining the two waves with a given polar
,7. A phase-responsive system for synchronizing
v ity and with the pulses thereof at least partially 75 a periodic-wave generator with an input periodic
2,410,523
8
wave' of’ an". integrally related frequency com
prising, means for combiningthe input wave with
for producing a scanning wave and means for
deriving a synchronization wave for controlling
a wavederived from the‘generator with’a given
polarity, means for individually deriving from
said scanning generator; a phase-‘responsive sys
tem for synchronizing said generator with said
said waves two waves of opposite polarity, means
synchronization wave comprising, means for com-v
for
vidually rectifying said two combined waves, and
means responsive to the difference in the outputs
bining said‘ synchronization wave with said
scanning wave, means for individually deriving
from said waves two waves of opposite polarity,
means for combining said opposite-polarity
waves, means for relatively time-displacing at
least one of said waves before combining, means
of said'rectifying means for controlling the fre
quency of said generator, whereby the synchroni
zation of said generator is substantially un
waves, and means responsive to the difference in
the outputs of said rectifying means for controll
combining said opposite-polarity waves,
means for relatively time-displacing one of said
generated waves before combining with the input
wave of corresponding polarity, means for indi
for individually rectifying said two combined
affected by spurious noise pulses superimposed on 15 ing the frequency of said generator.
said input wave.
8. A phase-responsive system for synchronizing
a periodic-wave generator generating a relatively
narrow pulse wave with an input periodic wave
comprising relatively broad pulses‘ and of an
integrally related frequency comprising, means
for combining the input wave with a wave derived
from the generator with a given polarity, means
’
10. In a television system including a generator
for producing a scanning pulse wave and means
for deriving an input synchronization pulse wave
for controlling said generator; 2. phase-responsive
system for synchronizing said generated pulse
wave with said synchronization pulse wave com
prising, means for combining the two waves with,
a given polarity and with the pulses thereof at
least partially coinciding in time, means for indi
for individuallyv deriving from said waves two
waves ‘of opposite polarity, means for combining 25 vidually deriving from said waves two waves of
opposite polarity, means for combining said op
said opposite-polarity waves, means for relatively
posite-polarity waves, means for relatively time
time-displacing one of said generated waves be
displacing at least one of said waves before com
fore combining with the input wave of corre
sponding polarity, means for individually rectify
bining, means for individually peak rectifying
ing said two combined waves, and means re
30 said two combined waves, and means responsive
sponsive to the di?erence in the outputs of said
rectifying means for controlling the frequency of
said generator, whereby the synchronization of
said generator is substantially unaffected by
spurious noise pulses superimposed on said input
wave.
‘ ' 9. In a television system including a generator
to the difference in the outputs of said rectifying
means for controlling the frequency of said gen
erator, whereby the synchronization of said gen
erator is substantially unaffected by spurious
noise pulses superimposed on said input
synchronization wave.
JOHN A. RANKIN.
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