close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2129726

код для вставки
Sept. 13, 1938.
-
A, w_ BARBER
2,129,726 - .
RECTIFIER CIRCUITS
Filed Jan. '50, 1956
I
'
i-i.
SOURCE OF 0. F9
-~—-||-H -
M
-
@
‘
/@
I2
SOURCE OF °_
INPUT
S'GNAI-
OUTPUT
‘
,C o.
<73 DEVICE
-/5
I
b
¢!\
+
.
°
d
Wmuwmm- H93
e
ii
'
'
A
Fly 4
+
4,
Fig.5
,
.
INVENTOR
WMBa/Léw
v, Patented Sept. 13, 1938
2,129,726
UNITED, STATES
PATENT OFFlCE
2,129,726
RECTIFIER CIRCUITS
Alfred W. Barber, Flushing, N. Y.
.
Application January 30, 1936, Serial No. 61,457
(c1. 250-27)
13 Claims.
This present invention of mine concerns im
Fig. 1 shows a circuit embodying my present
provements in electrical circuits. It particularly
invention-
relates to methods of, and means for recti?ca
tion in radio receivers and the like.
*5 ‘ One object of my‘invention is to produce a
recti?er circuit in which direct current products
vare cancelled out in the output. Another object
is to produce a recti?er in which the radio fre
quency drop across the recti?cation load circuits
l0 balance yielding an output voltage free from
.
Fig. 2 shows another form of my invention.
Fig. 3 shows a curve representing a modulated
radio frequency'wave.
5
Fig. 4 shows curves useful ,in explaining the
operation of the circuit of Fig. 1.
Fig. 5 shows curves useful in explaining the
operation of the circuit of Fig. 2.
In Fig. 1 I have shown a circuit embodying 10
'my present invention. A coil I receives a voltage
from the “source of input signal” which may
radio frequency components. A third object is
to produce a recti?er circuit in which the useful
demodulated alternating currents produced in
the output circuit, from a modulated radio fre
quency wave applied to the input, is the differ
ence between the products developed across two
be'a radio receiver up to the second detector or
it may be any other carrier wave amplifying or
coupling device. Coil I is magnetically coupled 15
to coil 2 although other types of coupling may
different load circuits.
be used, as for instance capacity coupling. One
end of coil 2 is connected to the two cathodes 4
and 5 ‘of the thermionic vacuum tube 3. Cath
odes 4 and 5 may be a single common cathode
In the past most recti?ers have been connected
so that when a modulated radio frequency volt
age is fed to the input, an output consisting of
useful demodulation‘ products, direct current,
since they are connected together.
The other
radio frequency and radio frequency harmonics
is produced. The undesired direct current is
usually removed by means of capacity coupling
25 to vfollowing circuits and the radio frequency and
‘its harmonics are ?ltered out. The capacity
coupling attenuates the low frequency desired
end of coil 2 is connected to the two plates or
anodes (Sand 9 thru independent load circuits.
The anode end of coil 2 is‘ connected to anode
6 of‘tube 3 thru the impedance of resistor "l
‘paralleled by condenser 8. Anode 6 is also con
nected to reference potential or ground point G.
demodulation products and the "radio frequency
The anode end of coil 2 is also connected to the
?ltering attenuates the high frequency desired
second anode 9 of tube 3 thru the impedance of
resistor If] and condenser H .in parallel. An
“output device” which willusually be an audio
‘frequency ampli?er, is connected between anode
9 and ground or reference point G at [2 and I3
output to a greater or lesser extent depending
on the precautions taken. My present systemv is
simple and yet produces less attenuation of low
and high frequency demodulation products than
most circuits by balancing out the direct current
C: CA and radio frequency voltages rather than ?lter
ing them out.
‘
respectively.
My system consists of a double diode, or two
Across one load circuit no desired de
modulation products are developed while across
the other load circuit the full range of desired
demodulation products is developed. In the out-‘
put circuit the drops across the two load circuits
45 ‘are subtracted, cancelling out the direct current
and radio frequency voltages but producing an
'unattenuated full range of desired demodulation
across coil 2 varies as in the case of a modulated
radio frequency voltage, condenser 8 discharges
thru resistor 1 when the voltage decreases and
charges thru ‘the diode consisting of cathode 4
and anode B when the voltage increases. How 45
completely the recti?ed voltage across condenser
8 follows the modulation of the voltage across
coil 2 is determined by the product of the ca—
products.
The appended claims set forth, in particular,
pacity of condenser 8 multiplied by the resist
the novel features to- be found in this invention.
ance of resistor l and the frequency of the volt 50
age change. The above condition also holds for
The following description, however, when taken
in connection with‘. the drawing, will serve to
the voltage appearing across condenser E i. Spe
set forth the theory and mode of operation of
55
my invention.’ '
_'
In the drawing, ‘
'
‘
'
.
When a voltage is induced in coil 2, recti?
cation takes place due to the action of the diodes 35
formed by cathode 4 and anode 6 and by cathode
5 and anode 9. The recti?cation causes con
densers 8 and H to charge up to the peak value
of the voltage appearing across coil 2 less the
drop across the rectifying diode. If the voltage
similar diodes, developing similar direct current
and radio frequency voltage drops across two load
40 circuits.
0
ci?cally, if
.
-
t
E
‘
-
.
.
55
2
2,129,726
equals about one tenth, then about ten percent
of the voltage change across coil 2 will appear
is adapted to direct automatic volume control by
using the drop across condenser 8 since the coil
across the load circuit while if
3
CT
is about eight or greater, the load drop will
almost completely follow the voltage variations
across coil 2. In the above formula t is the time
of one period of the voltage variation, 0 is the
capacity of the load condenser and 1' is the re—
sistance of the load resistor.
Ill paralleled by condenser ll. Cathode 4 is con
nected to the reference potential point G. Fig. 2
-
Fig. 3 shows a conventional modulated wave
with the modulation envelope shown. The line
0 represents the average of the radio frequency
voltage, b the peak amplitude of the modulated
wave and a the modulation envelope. Now, if
end of condenser 8 is negative with respect to
ground G and may be connected by lead I5 to the
control grids of amplifying tubes preceeding or
following the recti?er. Switch I4 is shown to
open or close the discharge path of condenser 8
thru the resistor ‘I.
If this recti?er is used in a 10
radio receiver, switch 14 may be opened for tun
ing purposes since it permits the build-up of
automatic volume control voltage in accordance
with the strength of the signal being tuned in
and since no discharge path is provided, holds the 15
sensitivity of the receiver constant during tuning.
Under these conditions the receiver may be tuned
by ear since the true selectivity is not obscured by
the action of the automatic volume control as
20 for condenser 8 and resistor ‘I of Fig. 1 at the
lowest modulation frequency is one tenth or less,
the voltage across condenser 8 will be maintained
substantially equal to ob the peak of the modu
lated wave since it will not follow the modulation
envelope. Fig. 4 shows line d representing the
voltage across condenser 8 under these conditions
where 011 equals ob of Fig. 3. Now, if
t
30
for condenser H and resistor I0 is eight or more
for the highest modulation frequency, the volt
age across the condenser H will follow the mod
ulation envelope of Fig. 3. The voltage across
condenser l I is shown by the difference between
d and e of Fig. 4. If point G at anode 6 is taken
as a reference point, the coil end of condenser
8 will have a voltage 0d with reference to point
G and the voltage across condenser II will sub
tract from the voltage across condenser 8 leaving
a net voltage between anode 9 and ground G equal
to ac as shown in Fig. 4. This net recti?ed out
put voltage shows the cancellation of direct cur
rent in such a way that, except for sudden
changes in modulation, the negative peaks are
always on the zero axis. This permits direct
conductive coupling of the detector to a follow
ing tube as shown by grid H5 in the “output de
vice” of Fig. 1. Also, since the radio frequency
voltage drops across the two resistor-condenser
loads are opposed. the radio frequency voltage
in the output is less than that in simple diode
circuits. This direct coupling and reduced radio
frequency permits reduced attenuation of both
low and high modulation frequencies over conven
tional recti?er circuits. The coil end of resistor
‘I may be used as a source of automatic volume
control voltage although in general phase re
versing means will be necessary.
The circuit shown in Fig. 2 is similar in theory
and operation to that of Fig. 1 except that the
recti?cation products are reversed in phase. Fig.
5 shows curve J‘ as the drop across the larger
time constant load circuit, curve in the drop
across the other load circuit and oh the net out
put voltage between cathode 5 and ground G.
This output is similar to the output from the
circuit of Fig. 1 except for the reversal in phase.
This reversal in phase is accomplished in Fig. 2
by interchanging cathodes and anodes of the two
diodes. Anodes 6 and 9 are connected directly to
one end of the input coil 2 while cathode 4 is con
nected to the other end of coil 2 thru resistor T
paralleled by condenser 8, and cathode 5 is con
75 nected to the cathode end of coil 2 thru resistor
described in my copending application Serial No. 20
25,390 ?led June 7, 1935, entitled “Automatic
sensitivity tuning.” Switch vl4 may also be used
for the same purpose in series with resistor 1
of Fig. 1.
The circuits of both Fig. 1 and Fig. 2 may be 25
used as control circuits in various ways. For in
stance if resistor 1 is heavily by-passed for modu
lation frequencies and resistor I0 is somewhat
less heavily by-passed, the output of the rectifier
will be a low frequency wave representing the
slow changes in average modulation which may be
useful as an automatic control voltage. A choice
between the connection of Fig. 1 and Fig. 2 will
yield the desired phase of control voltage. This
form of recti?er may also be useful in expansion 35
circuits on account of its property of frequency
component selection.
While thermionic vacuum tubes have been
shown and described as rectifying elements, other
types of recti?ers may be used such as crystals or 40
copper-oxide combinations.
While I have described only a few systems
whereby my invention may be carried into e?ect
and have pointed out only a few possible varia
‘tions, it will be apparent to one skilled in the
art that many modi?cations are possible without
departing from its spirit and scope as set forth
in the appended claims.
What I claim is:
Li
1. In a carrier wave receiver, a rectifying cir 50
cuit including a common input impedance, a
thermionic vacuum tube comprising at least one
cathode connected to one end of said input im
pedance and two anodes, each of said anodes
being connected to the other end of said input
impedance thru independent load circuits, a con
nection between one of said anodes and a point
of reference potential and a connection between
the other of said anodes and an output device,
wherein said load circuits are resistances shunted 60
by condensers, the time constant of one of said
load circuits being substantially greater than the
time constant of the other of said load circuits.
2. In a carrier wave receiver, a rectifying clr..
cuit including a. common input impedance, 2. rec- _
ti?er comprising two cathodes and two anodes, '
direct connections between said cathodes and one
end of said input impedance, independent load
impedances between each anode and the other end
of said input impedance, means whereby one of 70
said anodes is maintained at a reference poten
tial, an output circuit connected between the
other'of said anodes and said point of reference
potential, wherein each of said load circuits ex
hibits a substantially different time constant.
3
2,129,726
3. The method of generating modulation fre
quency voltages which comprises generating a
direct current voltage proportional to the peaks
of a modulated radio frequency wave, generating
a second voltage proportional to the instantane
ous value of the modulation envelope of said
modulated radio frequency wave said second volt
age comprising a modulation frequency com
ponent and a direct current component and sub
tracting one of said voltages from the other of
said voltages to produce a modulation frequency
voltage resultant having substantially no direct
current component.
4. In a carrier wave receiver, a rectifying cir
cuit including a common input impedance, two
pairs of rectifying elements, a low impedance cir
cuit between two similar rectifying elements and
one end of said input impedance, independent
load circuits connected between each remaining
20 rectifying element and the other end of said
input impedance, means whereby a direct cur
rent path in one of said load circuits may be
opened, and additional means whereby one of
said rectifying elements connected to one end
25 of one of said load circuits is maintained at a
reference potential.
I
;
5. In a carrier wave receiver, a rectifying cir
cuit including a common input impedance, a rec
ti?er comprising two- cathodes and two anodes,
a low impedance circuit between said anodes and
one end of said input impedance, independent
load circuits between each of said cathodes and
the other end of said input impedance, means
whereby one of said cathodes is maintained at a
'?Xed reference potential and an output device
connected between said two anodes, wherein said
load circuits differ substantially in audio fre
quency impedance.
6. The circuit as set forth in claim 5 wherein
40 said point of reference potential is ground.
7. The circuit as set forth in claim 5 wherein
each of said load circuits exhibits a substantially
different time constant.
8. In a carrier wave receiver, a rectifying sys
tem including a source of unrecti?ed voltage, two
pairs of rectifying elements, a low impedance
connection between two similar rectifying ele
ments and one end of said voltage source, inde
pendent load circuits connected between each re
50 maintaining rectifying element and the other end
of said voltage source, a low impedance connec
tion between one of said load connected rectify
ing elements and a point of ?xed reference po
tential, means applying the voltage drop across
the load circuit connected to said point of ref
erence potential to gain control means in said
receiver and additional means whereby a direct
current path may be opened in the last said load
circuit.
9. In a carrier wave receiver, two recti?ers
receiving carrier wave impulses and producing
output currents in two independent load cir
cuits, an output circuit receiving the combined it)
voltages developed across said load circuits con
nected in opposed polarity, in which the audio
frequency impedances of said load circuits are
substantially different.
‘
10. A circuit for generating a. ?rst demodula
15
tion voltage proportional to a carrier wave am.
plitude and a second demodulation voltage con
sisting of audio carrier modulation, comprising
two non-linear electrical conductors receiving
modulated carrier voltages and each producing an 20
independent output current in independent load
circuits, wherein the audio frequency impedance
of one of said load circuits is substantially less
than the‘other and means combining the de
modulation voltage drops in opposed sense to 25
form a useful output.
11. A circuit as described in claim 10 wherein
each of said load circuits comprises a resistor
shunted by a condenser and further means com
prising a switch in series with one of said re
sistors.
30
12. In an automatic volume controlled ampli
?er the combination of a recti?er including at
least a cathode and an anode, a circuit connected
between said cathode and said anode including 35
at least a signal responsive circuit and a series
connected condenser and a circuit shunting said
condenser including at least a resistance and a
switch connected in series.
7
-
13. In an electrical ampli?er the combination 40
of a grid controlled thermionic ampli?er tube, a
pair of rectifying elements, a load circuit compris
ing a resistor and a parallel connected condenser‘
connected in series with each of said rectifying
elements and an input circuit, a low impedance 45
conductive connection joining one end of each of
said load circuits, a low impedance conductive
ground connection to the other end of one of
said load circuits and a low impedance conductive
connection between the other end of the other of 50
said load circuits and the grid of said ampli?er
tube.
ALFRED W. BARBER.
Документ
Категория
Без категории
Просмотров
0
Размер файла
492 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа