close

Вход

Забыли?

вход по аккаунту

?

код для вставки
Sept. 27, 1949-
c. H. SMITH, JR., ETAL
2,482,303
ELECTRONIC SIGNAL SHAPING CIRCUIT
Filed Sept. 13, 1946
1155:..1.
(+)
(+)
f
I4
is
u/
.
o
"
l5
25¢”
1|\
-
i:
5;
'
-
.
SIGNAL
SOURCE —? "*WWWP“
l- |2 l8 I3‘
I 1152.51.
A
'
5+
I
B AVE. PLATE____
>
VOLTAGE
V
1
VOLTAGE
VOLTAGE
SQUARE WAVE OUTPUT
-
~
I
B+-AVE.PLATE
‘
____________I_SYMMETRICAL
MIN.PLAIE
C
SIGNAL FROM SOURCE n
‘
>
_____
_
_
_
_
.
____UNSYMMETR|CAL
SQUARE WAVE OUTPUT
MIN. PLAT_E_
VOLTAGE
'
.'
.
grvue/wbow
CARL HARRISON SMITH JR.
MILTON L: KUDER
Patented Sept. 27_, 1949 ‘
2,482,803
UNITED STATES rATENT OFFICE *
ELECTRONIC SIGNAL SHAPING CIRCUIT
Carl Harrison Smith, Jr.,
‘Va, and
Milton L. Kuder, Washingttm, D.
.
Application September 13, 1494's, Serial No. ‘696,980
3 Claims. (01. ear-2r)
(Granted under the act of March .3, 1883, .as
amended April 30, 1928‘; 337.10 0,. G. ‘7571)
1
.
invention relates to electrical signal gen
erating systems and in particular to systems for
producing symmetrical square-Wave signals over
.a wide frequency range and independent of varia
tions in power line voltage.’
.
many of the present forms of electrical
square-wave signal generator systems, a sinus
7
2
of the output square wave to maintain a central
:cl-ipping-regirm resulting in the production of sym
metrical square wave signals.
‘ V
'
With reference to the particular embodiment
oi Fig. 1, a clipping tube L0 is employed :as an
overedriven voltage ampli?er obtaining its grid
drive voltage from :a signal source ‘H through .a
.oidal signal having thefrequency of the desired
coupling-capacitance“. :Signal source l 1| is pref
erably adapted ‘to produce a ‘sinusoidal signal hav
square wave signal is ?rst generated andthen ap
plied to -a-cl=ipping stageror stages wherethe crests 10 ing a ‘frequency equal to that-of'the desired square
of the sinusoidal signal are““clipp.ed” 01f. For
wave output signal. Where it is desired that the
biasing considerations in the clipper stages it has
frequency of the square wave be ‘variable over a
usually been necessarywith previous systems to
frequency range, the signal source 'll
:be
capable of covering that frequency range. The
maintain the amplitude of the sinusoidal signal
applied thereto substantially constant otherwise 15 amplitude of the sinusoidal signal is preferably
a non-symmetrical square =wave output is .ob
tained. To maintain such a degree of constancy
in prior systems despite ?uctuations such as in
constant, however the ‘clipper circuit will operate
satisfactorily despite wide variations of input sig
nal amplitude :and frequency ‘such as would ac
{company ?uctuations in the supply voltage.
supply voltage, special oscillator control tubes or
20
[a regulated power supply were required.
The anode of tube II] is returned to a source of
Accordingly it is an object of’ the presentin
positive voltage through anode load resistance
vention to provide a signal generating system for
M‘. Voltage ?uctuations at the anode of tube Ml
producing symmetrical square wave signals in
are coupled to the output terminals l 5 through a
coupling (capacitance 1B andv the ground return
dependently .of ?uctuations in the voltages sup
plied
thereto.
.
g
.
.
Another object of the present invention is .to
provide in a square Wave signal generator system
employing a clipper tube, bias adjusting means
for the clipper tube maintainingsymmetr-ical
lead.
I
‘Bias for the control grid of tube i0 is obtained
in part ‘from the positive supply through anode
load resistance l4 and grid coupling resistance
I1 and in part from the capacitance 1'2 which be
square wave signal output.‘
30 comes charged as .a ‘result of grid current ?ow in
Other and further objects and features of the
tube l1] during .a. portion of the sinusoidal input
present invention ‘will become‘apparentyupon a
careful consideration‘ of the accompanying de
signal.
.
The sinusoidal signal from source ill as repre
sented by waveform A of Fig. 3 drives clipper tube
Fig. in a schematic diagram,.pa_rtly in block,. 35 Ill to alternate conditions of heavy anode cir
‘of a typical embodiment of ithe'fea‘tures of the
conductivity and anode circuit ‘cut-off. The
invention.
'
"1v
"
‘q
'.
positive ‘crests of the ‘input signal ‘drive the con-V
Fig. ‘2 is'a s-eries‘of waveforms taken to illus
trolltnrlid of tube 18 positive with respect tothe
trate more fully the operation of the circuit of
cathode resulting in control grid ‘conduction and
scription and drawing.
'
'
"
‘
'
'
‘Fig. l and the method of maintaining a substan
tially symmetrical square wave voltage output.
In accordancewiththe fundamental concepts
of the present invention ans'igna'l generator device
for producing square wave signals is provided in
which a symmetrical ‘square wave output is main
tained over a wide frequency range despite varia
40 monster-lent loss of signal voltage across limiting
resistance 13- to produce the ?attened out nega
'Ftiue portions of Waveform B, Fig. 2. 0n the op
posits half cycles of the driving signal ‘thee-clip
vper tube all! is driven to a condition of anode :cir
45 cuit cut-o? to produce the ‘?attened positive por
tions of waveform .13.
Mom wavetorm Bit is evident that :the circuit
as ltl‘iiHS {far described
produce a symmetrical
square vWave, having
durations of the nega
tions in voltages supplied thereto. Broadly, a
reference frequency signal of a sinusoidal char
acter is provided-to control the operation of the
system. This sinusoidal signal is then applied to v50 tive and the positive ?attened
portions only
a clipper tube Where the positive and negative
when the bias of tube I0 is critically adjusted so
crests are removed. Bits for the clipper tube is
“that the average grid potential :is midway be
supplied in part from the ‘plate circuit thereof
tween
required for anode current cut-on‘
through albias transfer network. This bias is
and for zero bias condition and is brought about
varied automatically in dependency on the shape‘ 255 by the action resistance! 1 to‘ offset "the charg
‘
2,482,803
3
ing of capacitance l2 during the periods of grid
current ?ow.
When the average bias voltage of
4
correspondence with the frequency of the desired
square wave signals, a clipper circuit compris
tube It] is not equal to this mid-value, an unsym
ing an electron tube having anode, cathode, and
metrical waveform may be produced such as that
control grid electrodes suitable for overdriven am
of C, Fig. 2 in which the lower ?attened portions Cl pli?er operation, an anode voltage supply for
said tube, coupling means transferring the sinus
are of shorter duration than the upper ?attened
oidal signal to the control grid electrode of said
portions.
electron tube in su?icient amplitude to consecu
To minimize ?uctuations in the average bias
voltage for tube 10 as a result of variations in
. tively drive said electron tube to anode current
the amplitude of the signal from source II and 10 saturation and anode current cutoff, said cou
attendant alternation in the average grid current
pling means comprising a series-connected com
drawn by tube I 9, the grid coupling resistance I1
bination of a capacitive element and a resistive
element whose free end is connected to the grid
is returned to the anode of the tube.‘ Resistance
electrode of said electron tube, an output circuit
I1 is purposely made large so as to operate with
capacitance l2 as an integrator circuit‘to hold to 15 operatively connected to the anode electrode of
said electron tube and to the anode voltage sup
a minimum the amount of the output square
ply therefor, and a resistive element operatively
wave fed back to the junction point I8 yet per
connected between said output circuit and the
mit ?ow of a unilateral charging current for
input circuit for feed-back to said input circuit
capacitance 12 to counteract the charging there
of a voltage proportional to the average voltage
of due to the flow of grid current within tube
existing in said output circuit whereby an average
III. In typical operation, an increase in the am
voltage of substantially zero volts is maintained
plitude of the signal from source ll would tend
in the input circuit at a point between the series
to raise the portion of the input signal of wave
connected capacitive element and vthe resistive
form A utilized for the production of the square.
element and whereby the square-wave voltage
waveform and consequently shorten the conduc—
signals developed in the output circuit is main
tivity period of the tube l0. Such operation
tained substantially symmetrical despite fre
would result in the production of the unsym
quency and amplitude ?uctuations of said ap
‘metrical square wave signal of waveform C hav—
plied sinusoidal signals.
ing a raised average level. This distortion of the
2. A generator device for producing symmetri
signal is counterbalanced by the action of the
cal square wave signals comprising a sine wave
connecting path between point [8 and the anode
signal generator, a clipper circuit fed by said
of tube Ill. The attempted rise in average po
sine wave generator comprising, an electron tube
tential at the anode of tube It] raises the poten
having an anode, a cathode, and a grid, a source
tial towards which capacitance l2 charges dur
of anode supply potential, a load impedance con
ing the time interval that the control grid of
necting said anode to said supply potential,
tube I0 is non-conductive and hence tends to
means including a series resistance coupling the
adjust the bias to restore the desired condition
output of said sine Wave generator to the grid
‘in which the central portion of the signal from
source ll causes the production of the output
of said tube, a second resistance connecting the
anode of said tube to the grid thereof through
square wave.
Satisfactory operation of the apparatus of the
said series resistance, a condenser disposed with
in the grid circuit of said tube in an integrating
invention constructed in accordance with the
schematic diagram of Fig. 1 was realized with
relationship with said second resistance, said sec
an output signal from source I 1 variable over the
ond resistance and said condenser cooperating to
frequency range of 2000 to 50,000 cycles per sec
change the grid bias on said tube in response
ond and over the amplitude range of 20 to 200
to changes in average anode potential on said
volts with the following circuit constants:
tube and in a sense corresponding to the sense
of anode potential changes.
Electron tube-Type 681-17
3. A clipper circuit comprising an electron tube
Anode voltage supply-—250 v. v
Capacitance I2--0.25 microfarad
Resistance l3--100,000 ohms
Resistance Id-22,000 ohms .
Resistance I‘l-4=.5 megohms
From the foregoing discussion it is apparent
that considerable modi?cation of the features of
.50 having an anode, a cathode, and a grid, a source
of anode supply potential, a load impedance con
necting said anode to said supply potential, a
pair of serially connected resistance elements
connecting the anode of said tube to the grid
thereof, a condenser, one plate of which is con
nected to the junction of said resistance elements,
the other plate of said condenser serving as an
device herein described and the form of appara
input terminal to the circuit, one of said re
tus for the operation thereof constitutes a pre
sistance
elements and said condenser cooperat
ferred embodiment of the invention it is to be 60 ing to change the grid bias on said tube in re
understood that the invention is not limited to
sponse to changes in average anode potential on
this particular device and form of apparatus and
said
tube and in a sense corresponding to the
that changes may be made therein without de
sense of anode potential changes.
parting from the scope of the invention as de
CARL HARRISON SMITH, JR.
65
?ned in the appended claims.
MILTON L. KUDER.
The invention described herein may be manu
factured and used by or for the Government of
REFERENCES CITED
the present invention is possible and while the
the United States of America for governmental
purposes without the payment of any royalities
The following references are of record in the
70 ?le of this patent:
What is claimed is:
UNITED STATES PATENTS
1. A generator device for producing symmetri
Name
Date
Number
cal square wave electrical signals,’ comprising; a
thereon or therefor.
2, 152,824
signal generator device for producing sinusoidal
signals of variable amplitude having frequency 75
Schlesinger ______ __ Apr. 4, 1939
Документ
Категория
Без категории
Просмотров
0
Размер файла
371 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа