close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2412682

код для вставки
Dec. 17,1946. -
w. D. HERSHBERGER
42,412,682
SWEEP OR PULSE GENERATOR
4Filed July s1, 1942
m
uw
2 sheets-sheet 1
Dec. 17,1946.
'
w.~ D. HERSHBERGER
‘ 2,412532
SWEEP 0R PULSE GENERATOR
Filed July 51, 1942
.
-> T
'
it
2 sheets-sheet 2
"upf
"
T
' ßnventor
Patented Dec. 17, 1946
¿naar
UNiEo stares LArtur
2,412,682
_
_
Y
sWEEP on PULSE GENERATOR
William nnershberger, Haddonfiela, N. J., as
signor to Radio Corporationof America, a cor
poration of Delaware
Application July s1, 1942, serial 510,453,088 v
5 Claims. (c1. 315-29)
My invention relates to cathode ray deflecting
circuits and particularly to deñecting circuits for
producing an exponential deñection to be used,
for example, in a radio pulse-echo system for
measuring the angle formed by a line from an
aircraft to a ship or other target and a perpen
dicular line from the aircraft to earth.
'I‘he pi'esent invention is an improvement on
the deflecting circuit of the pulse-echo system.
for measuring angles described in application
' Serial No. 452,989, ñled July 31, 1942, in the name
of Irving Wolff.
An object of the invention is to provide an im
proved de?lecting circuit for producing an ex
ponential deñection of a cathode ray.
A further object of the invention is to provide
an improved cathode ray deñecting circuit for
producing an exponential deñection without de
focusing the cathode ray during deflection.
The invention will be described for the purpose
of illustration as applied to a radio pulse-echo
system which radiates a signal downward and
forward from an aircraft whereby reflections that
are a measure of altitude will be received from
the earth directly below the plane while other
reflections will be received from the target ahead.
Since the ñrst occurring reñection will be a meas
.
2
,
driven positive by a voltage pulse during the
period this tube is made conductive.
y
The invention will be better understood from
the Yfollowing 'description taken in connection
with thel accompanying drawings in which
,
Fig. 1 is a block and circuit diagram of ap
paratus embodying my invention, Fig. 2 is a cir
cuit diagram of another embodiment of my in
vention, and Fig. 3 is a view of the end or the cath
ode ray tube in Fig. 1. In the severalñgures
like parts are indicated by similar reference
characters.
f
Referring to Fig. 1 of the drawings, a high fre
quency radio transmitter I2 is keyed by means
of a pulse keyer I3' and a keying pulse generator
ill to radiate short radio pulses downward and
forward from a suitable directive antenna system
iii. The transmitter pulses are also supplied over
a conductor 20 to a receiver 22 to function as
initial or time reference pulses. The keying pulses
preferably are applied to the keyer I3 through a
delay circuit I5. The antenna system I6 may be
two dipoles in parabolic reflectors which radiate
in overlapping left-hand and right-hand radia
` tion patterns, only one dipole and reflector being
shown in the drawings. The two dipoles are con
nected alternately to the transmitter I2 by means
ure-of the distance A perpendicular to the earth,
of suitable left-right switching means I‘I driven
the angle 0 between this perpendicular line and
by a motor I8. The transmitted pulses may occur
the line from the aircraft to the target can be
determined when the distance T1 to the target is 30 at the rate of 3500 per second and have a dura
tion of 0.3 micro-second; the switching from left
also known. The latter distance T1 is shown by
to right may occur at the rate of 60 per second.
.a later occurring reiiection from the target. From
These values are given merely by way of example.
the fact thatthe distance to the target divided
The reflected pulses are picked up by a suitable
by the altitude is the secant of the angle 6, the
antenna such as a dipole 2| and supplied to the
angle 0 may be calculated. As described in the
receiver 22 which ampliiies and demodulates
above-mentioned Woliî application, however, the
them. They are further ampliñed by an ampli
apparatus is so designed that the angle 0 may be
fier
23 and applied through switch arms 2li and
read directly on scale without the necessity of
25 to a pair of dei‘lecting plates 21 and 21a of a
The present invention provides a precise ex 40 cathode ray tube 29. A resistor 28 with a
grounded midpoint is connected across the de
ponential sweep or timing voltage that can be
ñecting plates 21 and 21a. The switch arms 24
applied directly to a pair of de?lecting plates of
and 25 are `operated synchronously with the left
a cathode ray tube without defocusing the cath
ode ray. In a preferred embodiment of the in 45 right antenna switching whereby the cathode ray
of tube 29 is deñected to give a left indication
vention two capacitors are connected in the plate
any calculations.
and cathode circuits, respectively, of two vacuum
`tubes which are made periodically current con
when the antenna radiation is toward the left
and to give a right indication when the antenna
radiation is toward the right. The alternate clos
ing of switches 24 and 25 is effectedV by means
ducting to cause sawtooth voltages of opposite
polarities to appear across the two capacitors. 50
of a suitable left-right switching mechanism
These sawtooth voltages are applied directly to
driven by the motor I8. The cathode ray tube
the two plates, respectively, of the pair of deilect
29 may be of conventional design and is pro
ing plates in the cathode ray tube. The vacuum
vided with a second pair of deflecting plates 3|
tube that has a capacitor in its cathode circuit
preferably has a screen grid electrode which is 65 and 3Ia positioned at right angles to the other
pair of plates. An exponential sweep or timing
2,412,682
4
tor 33 in the cathode circuit of tube 31 rather
than in the plate circuit. Capacitor 33 receives
its charge from a voltage supply 55 through the
voltage is applied to the plates 3l and Sla to de
ilect the cathode ray vertically at a repetition rate
of 3500 sweeps per second in the example being
anode-cathode impedance of tube 31 when said
impedance is lowered by the occurrence of a volt
age pulse P as will be explained below. The out
described.
My improved push-pull deñecting circuit is
especially adapted for supplying a suitable ex
put 'circuit of source 56 includes the usual bleeder
ponential voltage for use in apparatus of the
resistoi` 33 and ñlter capacitor 33. The tube 31,
above-described type. It comprises a variable ca
like the tube 33, is normally >biased to substan
pacitor 33 associated with a plate loaded tube 33
tially cut-off by means of vgrid circuit elements
and a variable capacitor 36 associated with a in @5 vandV 53, and preferably is provided with a
cathode loaded tube 31; The tube 34 -functions
parasitic reducing resistor 1. The path of the
as a discharge tube for capacitor 33 and may be
charging Vcurrent may be traced from the posi
a screen grid tube which is Ybiased substantially
to plate current cutoff by means of grid leak bi
tive terminal „of -source 36 through the tube 31,
the capacitor 33 to ground,'from ground through
15
asing provided by a resistor 39 and a capacitor
a voltage divider ¿resistor 58 and a bypass capaci
4l in the control grid circuit, for example. The
grid circuit of tube 34 preferably includes a low
resistance resistor 5 for reducing parasitic oscilla
tor 55 to a centering tap l0 located thereon, and
through a conductor 53 to the other terminal of
the source 53. At the end of a pulse P the ca
tions. Capacitor 33 receives a charge from a volt
age source 42 through thetube 34 upon the ‘ap
20
pacitor 33 >c_li'sch‘ar'ges through a cathode resis-tor
El, the ’conductor y59 and the portion of the ‘volt’
plication of a 'pulse P to the control grid ’40 `of
'age divider 53 located between »the centering tap
tube `3ft from the pulse generator 1'4. The >out
li) and ground. Here again the capacitor dis
put 'circuit of source ’42 includes the usual bleeder
charges completely Ybringing the upper terminal
resistorçS'l and >ñlt‘er 'capacitor 82. Thepuls'es P
of capacitor 33 to the centering 'potential rat tap
are applied from a 'generator I4 through a con 25 i3 whereby the upper end position of the cathode
di'ictor 44, an 'amplifier tube 46, an 'amplifier tube
ray sweep is independent of changes in the volt
41 and atra'ns‘forrner 48 which has a secondary
age amplitude of source 5B.
Y
l
winding 3 that is damped by ‘a ’shunting resistor.
The centering circuit disclosed lin this appli
The cl'iargihg path for 'capacitor 33 'may be
cation is described and claimed in copending‘ap
traced'frbm the positive tfrm'in'al of voltage source 30 plication Serial No. 455,409, ñled'August 20, 1942,
42 through a conductor 35 and a section of jthe
volta/ge divider V58 and lits bypass capacitor1 33 'to
ground, through "round tov the lower terminal of
'capacitor 33, and through the capacitor 33 and
-the plate-'cathode >irnpeda'nce 'of tubes 34 to the
rnegative .terminal ‘of the 'voltage source 42. At
the énd of the pulse P’the capacitor 33 'discharges
through a 'path that ìîì’íály be traced from vthe up
'perl terminal 'of capacitor 33 _throughjthe Vresistor
"E3 ofV tube 34, the conductor 35, a section of volt
age divider v58 >and its bypass capalcitoï` 3B to
ground, and through 'ground 't'o the lower termi
nalo'f capacitor 33.
`
'
v
in the name of Max H. Mesner, and-entitled Ex
ponential deflecting -and `centering circuits.
In the particular -equipn'len' being described,
the time constant of the sweep circuit 33-43
(or circuit 33-3i), when set to _measure the
maximum altitude, ‘such as l210,000 feet, is about
one-fifth the _period of the vertical sweep, this
being the condition for maximum resistance and
maximum capacitance in the ’sweep circuit and
for the least amount of discharge Of ‘the Capaci
tor 33 (and of capacitor 36) at the end 'of the
sweep. Even for this condition capacitors 33 "and
33 are ‘substantially -completely discharged; spe
It should be not'd that the Acaps'alcitor 33 ‘al
ciñcally, if the charging voltag'erfro'm -source '42
ways 'discharges 'completely 'to bring 'its upper
is'2000 volts, the capacitor 1'3_3discharg`es to '1 for 8
terminal l(and also the deflectin'g ‘plate 31) to the
volts which ‘is ‘such 4'a >small percentage v’of the
'centering ~potential 'at >the 'tap l1. It is 'at the
'charging voltage 'that the failure to discharge to
'vend of the discharge period that the cathode ray
Zero volts‘does n‘ot affect the'operation.
_ y
is "at the upper ën'd‘of 'its sweep. It lfollows that
'Referring 'again ‘to the 'charging 'period forca
changing 'the amplitude 'of V‘voltage 'from ‘soul-'ce 50 paì'iito'r 36, the VVplate-‘cathode impedancejo'f >tube
“4,2 does hot _affect the centering jat 'this ‘end 'of
31`is lowered "during theV occurrence‘of‘each pulse
the V'sv'vee’p so -far as -Öapa?lí’tor 33 `i`s concerned.
P 'by applying these pulses ysimultaneously >toits
The same ‘is true with respect to _capacitor '33 as
'control -grid 32 and to 'its `>screen 'grid :33. 'lIÈhe
will immediately be apparent. The lower Iter
>control 'grid 'B2 vreceivesY its >pulse Vthrough the
55
minal ofvj'capa'c‘itor ,'33 may be ‘connected to ’the
‘8 :of transformer '48 while Athe -`screen
‘secondary
negative îterminal of ‘voltag'e'sourc‘e '112 instead ‘of
grid V63 receives its pulse ‘thro-ugh Vvan ’amplifier
to -ground,'if desired.
^
tube 6d 'and >a transformer 63, the l¿tube ‘34 being
Y The 'sweep voltage appearmgacross capacitor
coupled to the anode circuit of Aam'pliñer-tube I6.
33 is shown ‘at 5I. It has a’ Awave shape that
The secondary Vt and the vsecondary >of `»trans
lsavìltçmth
4wave
>may ’be described as a non-linear
forn'ier-«GE are shunted by vdamping resistors. It
shape, the useful 'deñecting portion ’of the `saw
will -be noted that the voltage Ípulses are «applied
tooth'being exponential, 'that is, being Í‘fben't over”
to theïgrids-52 `and 63 with respect vït'o the cathode
in accordance with the discharging of 'capaci-tor
31 of Itube 31, 'not with -respect `ïto ground. As la
133 through resistor 43 at anfe'xponential rate.
Preferably 4during each pulse P the Acapacitor 33
is fully charged andat the Afend >of eacnelischarg
ing period it is completely discharged. The volt
age‘wave >5I is applied` over -a conductor 52 di
65
result, it "is ípossible to-'operateï‘tube 3¿1'=wi'thigood
gain wherebyno îdiflicultyfis encounteredin driv
ing the Ttube 31 vfronti its 'normal -ahodeïcurrent
lcut-olf condition t'o Élow anode-cathode lirripeti
ance Iby a pulse-Pof reasonable amplitude. ’ _The
reason for applying the fv'oltag'e ïpulses ¿to the
70
The sweep voltage appearing "acro‘ss Vcapacitor
screen grid '63 44as well as tothe control grid l:(52
rectly to the deflecting plate Y3| .
,
33 is shown jat 53. It has the same wave shape
as the voltagewave _5| but is of opposite polarity
_
»and
>is applied overr 'ajconductor 54 directly 5to
the ydeflecting plate ‘3121. The Vdesired A'polïaïrity of
the wave 53 is obtained by connecting the capaci
is that -the cathode ,61ïswingsïpositiveáabove‘ground
potential when ‘capacitor 36 ‘receives itscha'rge.
-By «applying-'a -pulse "to the screenfgïridïœ fat'this
75 time, it is brought to the proper positive poten
entre
6
tialwith respect to the cathode 61. Care is taken
tomake the secondary windings of transformers
of theV sweep trace does notchange its position
481and 66 have low capacity with respect to the
pulse moves off the scale.
primary windings` whereby the secondary wind
(6) The angle 0 for a target thai-,reflects a
pulse T1 (Fig. 3) may now be- read directly from
and no further centering is required. The initial
ings can readily swing above ground potential.V
My improved sweep circuit does not defocus
the cathode ray during the sweep deflection be
cause the deñecting voltage waves 5l and 53
swing the deflecting plates 3| and 3io, respec
tively, about ground potential, this also> being 10
substantially the potential of the second anode
Y
.
.»
'
the point on the angle scale opposite thepulse
T1. The reason that the angle 0 and the altitude
can-be determined in the manner described above
has been more fully described in the above-iden
tiñed Wolff application b-ut need not be repeated
here.
-
'
„
`
» From the foregoing it will be seen that altitude
`(SSofcathode ray tube 29. The second anode
may be read from the dial 'Il andthe angle 0 from
potential may be adjusted by means of a movable
the scale on the cathode ray tube 29. At the
ltap 69 on a potentiometer resistor 'H which has
its ends connected to opposite sides of a grounded 15 same time the indications reveal whether the
Y target sought is to the right or left of line of
point on the voltage divider 58.A
night of the aircraft. This is accomplished by
the alternate antenna switching previously ’de
lfilter units supplied with power from an A.-C. line
scribed which is done at a superflioker rate. A
through a voltage control unit 'l2 such as a
“Variac” and through a transformer 13. Ad 20 visual comparison between the amplitudes of the
pulses corresponding to the echoes from the left
justment of the tap marked “Vertical size” adjusts
and right is made to determine the direction in
the .amplitude of the vertical sweep. The pri
which the target lies.
.
‘
. .
'
mary Winding of transformer 'I3 has a midtap
It will also be apparent that ‘a precise ~ex
and an end tap, indicated by the legends “Angle”
and “Set-up,” respectively. By moving a switch 25 ponential sweep deflection is provided without de
iocusing the cathode ray of the indicator Stube.
arm 14 from its “set-up” position to its “angle”
The precision of the sweep is insured by the fact
position the voltage supplied by the units 42 and
that the voltages appearing across capacitors 33
56 is doubled and the amplitude of the vertical
and 3% are applied directly to the deiiecting plates.
.sweep is doubled.
In the drawings the values of various circuit
The Variable capacitors 33 and 33 are mechani 30
elements have been indicated, merely by way of
cally coupled to a dial pointer 'IS associated with
example, in ohms and microfarads.
an altitude scale '11. Thus the pointer 'F6 ro
In Fig. 2 the vertical sweep circuit is similar
tates when a knob 18 is rotated to change the
to that of Fig. l but the negative terminals of
capacity Vof capacitors 33 and 36 for the purpose
of “set up” and for obtaining altitude as ex 35 the voltage sources ¿l2 and 53 are grounded and
the centering is accomplished by means of ade
plained below. In the example being described,
iiectìng coil 86 supplied with direct current from
each of the capacitors 33 and 38 has a capacity
a battery or other suitable source 81. The upper
range from 150 mmf. to 550 mmf.
end of the vertical sweep at the end of Ítube
VThe procedure in setting up and reading the
29 is brought opposite the 90 degree mark by
altitude and angle scales, is as follows:
adjusting a centering tap 88.
l
(1) The switch 'lli is thrownv to the “set up”
A minor difference between Figs. 1 and 2 is that
position shown in the drawings so that one-half
in Fig. 2 the tube 34 is biased substantially to
full deiiection voltage is applied from capacitors
'cutoff by cathode biasing instead of by grid. leak
33 and 36 to the vertical deiiecting plates 3l
biasing. "A more important diiïerence is vthat
and 31a.
in Fig. 2 the screen grid 53 and the control grid
(2) The end of the vertical sweep or cathode
32 of tube 3l have the pulses P applied thereto
ray trace is brought opposite the 90 degree mark
The voltage sources d2 and 53Y are rectifier
from the same amplifier tube 64 instead of from
diiîerent amplifier tubes.
It will be understood that the circuit of Fig. _2
(3) The initial or time reference pulse I. P. 50
operates the same as the circuit of Fig. 1 except
(Fig. 3) is then brought opposite the Zero mark
at the top of the angle scale by adjusting the
centering tap I0 on voltage divider 58.
`
-as to the diiîerences mentioned above.
at the bottom of the angle scale by means of the
I claim as my invention:
“vertical size” tap. With my deflecting circuit it
1. A cathode ray deflecting circuit comprising
is not necessary to re-center to keep the end of
an electric discharge tube having a control grid
the trace opposite the 9G degree mark since the
capacitors 33 and 35 always discharge to the cen
circuit and an anode circuit, a capacitor and an
tering potentials whereby the upper end of the
anode resistor located in said anode circuit,
means for charging said capacitor through said
trace remains ñXed.
tube in response to the application of lperiodical
(4) The altitude echo pulse A (Fig 3) is next
brought opposite the 60 degree mark, which is at 60 ly recurring pulses to said control grid circuit,
means for discharging said capacitor through
the mid-point on the angle scale, by rotating
the knob 'I8 and thereby adjusting the rate of
said resistor, a second electric discharge .tube hav
discharge of capacitors 33 and 38. This is the
ing a control grid, an anode and a cathode, a ca
adjustment that brings the Voltage across capaci
pacitor connected between said cathode and a
tors 33 and 38 to one-half the initial voltage 65 point that is negative with respect to said cath
ode, means for charging said last capacitor
value and the indication then occurs at the 60
through said second tube in response to the ap
degree mark'. Rotation of the knob 'i8 also ro
plication of said pulses to the said grid of said
tates the pointer ‘IE of the altitude scale from
second tube, a cathode resistor for said second
which the altitude may now be read.
(5) The switch ‘M is next moved to its “angle 70 tube, and means for discharging said last ca
pacitor 'through said cathode resistor whereby
measuring” position putting the full sweep voltage
sawtooth deiiecting voltages of opposite polar
on the vertical deñecting plates whereby the
ity appear across said capacitors.
length of the vertical sweep is doubled. This
2. A cathode ray deñecting circuit comprising
brings the altitude pulse A to the zero mark on
the angle scale. As noted above, the upper end 75 an electric discharge tube having a control grid
2,412,682
vm
i
circuit and an anode circuit, .a capaci-tor located
in said anode circuit, means for «alternately sub
8
anode resistor located in said anode circuit, means
for charging said capacitor through said tube in
response to the application of periodically re
stantially completely charging said capacitor and
substantially completely discharging said capaci
curring pulses .to said control grid circuit, means
tor in response to lthe application of periodically si for discharging said capacitor through said re
sistor, a second electric discharge tube having a
recurring pulses to said control grid circuit, a
second electric discharge tube having a control
control grid, a screen grid, an anode and a cath
ode, means for so applying said pulses to said
grid, a screen grid, an anode and a cathode,
last named grids as lto vdrive them positive with
means for so applying said pulses to said last
named grids as to drive them positive with re 10 respect to the cathode of said second tube, >a ca
pacitor connected between said cathode and a
spect to the cathode of said second tube, and a
capacitor connected between said cathode and a
point that is negative with respect to said cath
ode, and means for alternately substantially com
pletely charging said last capacitor and substan
tially completely ydischarging said last capacitor
inresponse to the application of said pulses to the
said grids of said second tube.
3. A cathode ray deflecting circuit comprising
an electric discharge tube having a control grid :20
point that is negative with respect to said cath
ode, means for charging said last capacitor
circuit and an anode circuit, a capacitor located
in said anode circuit, means for alternately sub
circuit vand an anode circuit; .a capacitor and an
anode resistor located in said anode circuit, means
stantially completely charging said capaci-tor and
substantially completely discharging said capaci
for charging said capacitor through said tube in
_response to the application of periodically re
tor in response to the application of periodically
recurring pulses to said control grid circuit, a
ysecond electric discharge tube having a control
curring pulsesto said control grid circuits, means
for -discharging said capacitor through said re
through said second tube in response to the ap
plication of said pulses to the said grids of said
second tube, a cathode resistor for said second
tube, and means for discharging said last ca
pacitor through said cathode resistor.
5. A cathode ray deflecting circuit comprising
an electric discharge tube having la control grid
sistor, a second electric discharge tube having a
` control grid, a screen grid, an anode and a cath
grid, a screen grid, an anode and a cathode,
ode, means for so applying said pulses to said last
means for so applying said pulses to said last
named grids as to drive them positive with re 30 named grids as to drive them positive with re
spect to »the cathode of said second tube, a ca
spect to the cathode of said second tube, and a
capacitor connected between said cathode and a
pacitor connected between said cathode and a
point that is negative with respect to said cath
ode, means for charging said last capacitor
.pletely charging said last capacitor and substan 35 -through said second tube in response to the ap
tially completely discharging said last capacitor
plication of said -pulses to the said grids of said
in response to the application of sai-d pulses to the
second tube, a cathode resistor for said second
said grids of said second tube, a cathode ray tube
tube, means for discharging said last capacitor
having a pair of deflecting plates, and means for
through said cathode resistor whereby sawtooth
deflecting voltages of opposite polarity -appear
applying the voltages appearing across said ca
pacitors to said deflecting plates in push-pull re
across said capacitors, a cathode ray tube hav
ying a pair »of de?lecting plates, and means for ap
lation.
plying said deflecting voltages directly .to said
4. A cathode ray deilecting circuit comprising
deñecting plates.
an electric discharge tube having a control grid
circuit and an anode circuit, a capacitor and an
WILLIAM D. HERSHBERGER.
point .that is negative with respect to said cath
ode, means for alternately substantially com
Документ
Категория
Без категории
Просмотров
0
Размер файла
764 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа