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Патент USA US2411062

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Nov. 12, 1946.
2,411,062 ‘
Filed June 24,‘ 1942
/v .
Ono H. cnADE‘
Patented Nov. 12, 1946
‘ 2,411,062
' 0m H. Schade, West Caldwell, N. J., assignor to
1 Radio Corporation of America, a corporation‘of
. ‘
'YApplication‘June 24, 1942, Serial Nb. 448,210 , ‘ '
4 Claims.
(Cl. 250—-36)
_ This invention relates to circuits for produc
nected to the coupled primary windings 3 and 5
ing-electrical impulses, and particularly to block
ing impulse generators. A blocking impulse gen
of a transformer ,‘I. so asto‘ feed back energy
from the plate circuit to the grid in such polarity
erator‘is a circuit which is normally quiescent,
he, the voltages at‘various points in-the circuit
as to tend to produce oscillation at a frequency
‘ determined by the circuit'constants. A resistor
remain constant, until a ‘trigger or control im~
pulse is applied, whereupon the circuit voltages
I I is connected in the cathode circuit of the tube
I, and a resistor 9 is connected from the positive
vary through an operating cycle and then resume
plate Voltage supply terminal to the resistor II.
their former values. Such circuits usually com
Current ?owing from the plate supply (not
prise an oscillator of some sort, biased to prevent 10 shown) through the resistors 9 and II produces
oscillation. The‘ blocking bias is momentarily
a voltage drop in'the resistor II suf?cient to out
overcome by the trigger impulse, the oscillator
off the tube I and prevent oscillation.
A resistorv I3 is connected in the grid A.-C.
return circuit in series with the transformer
output pulse are determined by the constants of 15 winding 5, so that a positive voltage impulse I9
the oscillator circuit while the trigger pulse de
applied across resistor‘ I3 will overcome the grid
termines only the time at which an output pulse
biasing effect of the voltage drop on the resistor
is‘ initiated. Circuits of the described type ?nd
II._ Control impulses I9 may be applied to the
goes through one cycle, and is blocked again.
The duration, wave shape and amplitude of the
application, for example, in de?ection circuits
for cathodeiray tubes.
A ,
It an object of the invention to provide an
improved method of ‘(and means for producing
circuit at a terminal I5, which is connected
20 through a capacitor IT to the resistor I3.
pulses of‘predetermined duration, amplitude, and
value of the capacitor I1 is selected with refer
ence to ‘that of the resistor I3 so that a pulse I9
applied at‘the terminal I5 will be differentiated
wave} shape at a repetition rate determined by
to provide a sharply de?ned pulse ZI at the be
the frequency of‘ a controlling pulse.
25 ginning of each controlrpulse I9.
A further object is to‘ provide an improved
The ‘circuit will oscillate for one-half cycleas
method of and means’ for producing pulses hav
each pulse ‘ZI reaches the grid circuit, producing
ing duration, amplitude and wave shape inde
an output pulse 23‘ at the secondary 25 of the
pendent of their repetition time and. independent
transformer ‘I. At the end of the half cycle, the
oithe wave shape of the pulse used to control 30 voltage fed back from the plate circuit to the
grid circuit cuts off the tube I because of the
‘Another object of the invention is to provide
charge on capacitor I8 and the tube remains cut
an improved method of and means for maintain
off by the voltage across the resistor II until
their repetition time.
ing constant‘ pulse shape and duration without
another pulse 2| arrives at the grid circuit. Thus,
circuit adjustments over a wide range of pulse 35 the repetition frequency of the output pulse is
Still another object is to provide a method of
determined solely, by that of the control pulse
I9, while the wave shape, duration, and ampli
‘and‘means for producing pulses of predetermined
tude of the output pulse depend on the oscillator
duration and wave shape having a predetermined
circuit and are independent of frequency.
time delay with respect to their respective con 40 Referring to Fig. 4, the curve a. represents the
trol impulses, independent of the repetition rate.
voltage across the, resistor I3 as a function‘of
Other and incidental objects will become ap
time, the curve 2) ‘represents the total voltage
parent to those skilled in the art upon considera
between the grid and the cathode of the tube i,
tion‘ of the following description with reference
and‘ the dotted linec represents the ‘voltage across
to the'accompanying drawing, of which Fig. 1 is 45 the resistor II.
, ‘
Referring to Fig. 2, a blocking impulse gen
a circuit, diagram‘ of a transformer coupled
blocked oscillator type impulse generator, Fig. 2
erator including a multivibrator circuit is illus
is a circuit diagram of a blocked multivibrator
trated. R'I'he multivibrator circuit is of the type
type'impulse generator and Fig. 3 is a schematic . described inU. S. Patent No. 2,157,434 to J.‘L.
diagram of a pulse delay circuit. Figs. 4, 5 and 6 50 Potter, and“ comprises tubes 29 and 3| provided
are graphical representations of the wave forms
of voltages appearing at various points in the
circuits during the operation of the devices shown
in Figs. 1, 2 and 3 respectively.
Referring to Fig. 1, a vacuum tube I, is con 55
with a common cathode resistor 33 and plate load
resistors 35 and 31. The plate of the ?rst tube
29 is coupled through a capacitor III to the grid
of the second tube 3|, which is connected to
ground through a grid leak 43. The various cir
cuit constants are so proportioned that cyclically
repeating voltage pulses would be produced across
the resistors 33 and 31, if the circuit were al
lowed to operate as described in the said Potter
pulses 25| and 253, illustrated in Fig. 6 by the
This type of operation is prevented by a re
sistor 21 connected between the positive terminal
of the plate voltage supply and the common
curves e and 1‘ respectively. The delay of the
output pulses over the corresponding control
pulses is controlled by the time constant repre
sented by product of the resistor I35 and the cae
pacitor MI, and is independent of the repetition
frequency of the pulse I49.
I claim as my invention:
1. A pulse generator comprising two oscillator
through the resistors 21' and 33, producing suf? 10 devices including elements so proportioned that
said devices tend to oscillate and block at a fre
cient voltage drop on the resistor 33 to cut off
quency higher than the repetition frequency of
the second tube 3|. A resistor 44 is coupled to
the highest frequency pulse to be generated;
the grid of the ?rst tube 29 through‘a capacitor
means for applying a bias to each of said devices
45 so that a negative voltage impulse 49 applied
across the resistor 44 througha capacitor 41 will 15 to prevent oscillation; means for applying a pul
sating controlvvoltage to one of said devices to
reach the grid of the tube 29 in the proper
momentarily overcome said bias on said ?rst de
polarity to reduce the positive grid bias of tube
29 momentarily causing an ampli?ed positive‘ im'
‘vice' in response to each pulse of said control
voltage, whereby said ?rst device produces, in
pulse on the grid of the tube 3|, which in turn
causes the circuit to produce, by current feed~ 20 response to each pulse of the control voltage, a
pulsehaving a‘ duration time determined by the
back in resistor 33, one pulse 5| in the plate cir
cuit of the tube'3I. The duration of the pulse
circuit elements of said. ?rst oscillator device;
means for deriving a voltage proportional to the
5| is controlled predominantly by. the product
rate of change of the output voltage of said. ?rst .
of the resistor 35 and the capacitor 4|, and is
independent of the repetition time, which is con 25 device, and applying said derived voltage to ‘said
second oscillator device to overcome momentarily
trolled by the input pulse 49. The time constant
said bias at the end of each pulse of the. output
represented by the product of the resistor 43 and
cathode circuit.
Current from the‘plate ?ows
voltage of said?rst oscillator device.
the ‘capacitor 4| must be less than one-third of
2. A pulse delay circuit comprising two nor
the minimum pulse repetition time in order to as
sure discharge of the capacitor 4Ibefore occur 30 mally blocked oscillator devices; means for. ap
plying-a control signal to one of said oscillator
rence of the triggerv pulse. A» pulse 53 similar to
the pulse 5| but of- opposite polarity appears
devices, and high frequency pass filter. means
simultaneously across the resistor 33.
connected to the ?rst of said oscillatondevices
.for applying the output offthe ?rst of saidos
voltage across the resistor 43,. and the curve I) 35 cillator devices to the second of said devices.
3. A system for producing. a’ pulse in ‘response
represents the resultant voltage at the grid of
to a control pulse ata predetermined'time after
the tube 3|, for a fairly high repetition rate.
Referring to Fig. 5, the curve it represents the
the occurrence of said control pulse comprising
For lower repetition rates the; pulse decay occu
two normally blocked oscillator devices; means
pies a smaller, percentage of the totaltime per
40 for applying said control pulse to one of said, os
cillators to cause said oscillator togproducevv an
A circuit for producingna pulse of predeter
output pulse of predetermined duration;- means
mined wave shape‘ and amplitude a predeter
mined time after the occurrence of a controlling
pulse is shown in Fig. 3. Two blocked multivi
brators 55 and 51, each like ,thefdevice shown. in
for. deriving from said output pulses. voltage pro
portional to the time ‘derivative of said-output
Fig; 2, areemployed. The elements of the devices
otherof said oscillator devices.
55 and 51 are. designated by the same reference
numerals as the corresponding elements of the
pulse and for applying said-derived .voltageto the
4. A system for producing .pulses- of predeter-
minedmagnitude and Wave shape and a repeti
tion frequencydetermined by that of a pulsating
v50 control voltage, comprising two electron :dis
charge tubes each including a cathode,v an-anode
The output of the. multivibrator 55 across‘ a
anda control grid,» a source of‘ anode potential
resistor I33 15' coupled through a capacitor 241
circuit of Fig. 2, with pre?xes I and .2 respec
' vto a resistor 243 in the control input circuit of
the multivibrator 51.
The operationnof the multivibrator 55 is ex
actly like that of the device of vFig. 2. A control
pulse I49 applied to the resistor I43 through
the capacitor I4'I produces .a voltage shown by
the curve b of Fig. 6, which overcomes the block
ing bias on the tube -I3| and produces a. voltage 60
shown by the curve 0 of Fig. 6Yacross the resistor.
I33. The pulse duration of the voltage 0 is
largely determined- bythe product of the re
sistor I35 and the capacitor, MI. The voltage. 0
connected to the anodes 'of'said. tubes through
load’ resistors andto the (cathodes of- said'tubesh
through a common cathode resistor, means for
coupling the anode of the ?rst of 'saidltubes to
the control grid of the secondof said tubes
whereby said tubes tend to oscillate at a-fre-v
quency higher than that ofith'e highest frequency
pulse to be generated, a resistor connected’be
tween the positive terminal of said source- of.
anode potential andv said cathodes .to provide
su?ieient drop in said cathode resistor to bias said
secondtube to cut'o'tl’fa resistor connected'bee
tween said positive terminal'andlthe control grid:
is diiierentiated by the capacitor >2‘4liand the
of said first tube, and‘ means for app1y'ingsaid
resistor 243, resulting ina voltage‘ ‘at thegrid of
pulsating control‘ voltage to the control grid‘ of
the tube 229. showniby the» curve d of Fig. 6'. The
negative pulses of the voltageTd lagwthe corre
sponding-control pulse ,fronts by the pulse dura
tiontime of the voltage c,,and produce‘ output 70.
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