close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2129078

код для вставки
Sept. 6, 1938.
E, ZEPLER
2,129,078
AUTOMATIC VOLUME CONTROL CIRCUIT
Filed Sept. 2, 193a
MIAAVAVAVMA
[7C HIV!
INVENTOR
ERICH ZEPLER
ATTO RN EY
2,129,078
Patented Sept. 6, 1938
Y‘ ‘UNITED STATES PATENT OFFICE
2,129,078
AUTOMATIC VOLUME CONTROL CIRCUIT
Erich Zepler, Chelmsford, England, assignor to
Telefunken Gesellschaft fiir Drahtlose Tele
graphic in. b. H., Berlin, Germany, a corpora
tion of Germany
Application September 2, 1936, Serial No. 99,032
In Germany September 17, 1935
4 Claims.
The present invention relates to an arrange
ment adapted to compensate for attenuation
of high modulation frequencies caused by unduly
narrow or peaked resonance curves.
It is known from actua1 practice in radio re
ception that there occurs often an undue cut-off
of the side-bands, and thus a weakening of the
high pitched notes, because of the abrupt drop,
or the steepness, of the flanks or sides of reso
10 nance curves. To be sure, this undesired cut-off
may be avoided to a certain extent by the aid
of band-pass ?lters, though a great number
thereof must be provided in order that adequate
steepness of the ?anks of the resonance curves.
(Cl. 250-20)
frequency waves should prove to be insu?icient,
it would be possible, for instance, to insert an
RF choke in lieu of a resistance. The letters NF
denote the audio frequency path for utilizing the
audio voltage developed across diode load re
sistor W3.
What is claimed is:
1. In a radio receiver of the type comprising
a signal transmission tube and a single recti?er
in cascade, said transmission tube having signal 10
carrier selector resonant networks associated
therewith which are su?iciently sharp to pro
duce attenuation of the higher modulation sig
nal frequencies, means in circuit with the recti
?er producing a direct current voltage whose 15
15 may be obtained to thus prevent undue impair
ment in selectance. Another way and means to
establish balanced and uniform conditions con
value varies directly with the carrier amplitude,
only a single network for applying said Voltage
sists in that, in the audio network, the low
pitched notes are slighted in comparison to the
20 high audio frequencies. However, this is of
network being chosen sufficiently low so that the 20
gain of the transmission tube is less for low
great disadvantage insofar as in the case of disk
reproduction of sound, uniform ampli?cation or
even a preferential treatment of the low audio
frequencies is desirable.
For these reasons another procedure is dis
closed in this application whereby the said draw
backs are obviated. The present invention con
sists in that the time-constant of automatic fad
ing compensation, or volume control, is chosen
30 so low that the ampli?cation, for low modulation
25
frequencies, is less than for the high frequencies.
In the drawing is illustrated an exempli?ed
embodiment adapted to practicing the present
invention. From the aerial the radio frequency
35 potential is fed by way of the radio ampli?er
HF’ and coupling means (not shown), or addi
tional stages, to the recti?er G which, in this
instance, furnishes at the same time the regu
lator, or biasing, voltage. In the exempli?ed em
bodiment here illustrated two ?lter units, or
meshes, are provided through which the regu
lating voltage is applied. The resistances W1 and
W2 as well as the condensers C, C1 and C2 must
be chosen sufficiently low, but not too low to
45 prevent the high notes. being compensated away.
The low frequencies are attenuated by that, upon
an increase of the radio frequency amplitudes,
the gain or amplification is reduced, while upon
a rise (at the frequency of the low notes) the
50 gain is raised with the result that at the output
end of the radio frequency ampli?er the high
frequency oscillations will be less modulated by
the low notes.
If because of the reduction in value of the re
65 sistances W1 and W2 the ?lter effect for the high
to the transmission tube in a sense to reduce the
gain thereof, and the time constant of said last
modulation frequencies than‘ for the aforesaid
higher modulation frequencies whereby the said
attenuation is compensated for.
2. In a radio receiver of the type comprising N)
a signal transmission tube and a single recti?er
in cascade, said transmission tube having signal
carrier selector resonant networks associated
therewith which are su?iciently sharp to pro
duce attenuation of the higher modulation signal 30
frequencies, means in circuit with the recti?er
producing a direct current voltage whose value
varies directly with the carrier amplitude, only
a single network of at least two ?lter meshes for
applying said voltage to the transmission tube 35
in a sense to reduce the gain thereof, and the
time constant of said last network being chosen
su?iciently low so that the gain of the transmis
sion tube is less for low modulation frequencies
than for the aforesaid higher modulation fre- 40
quencies whereby the said attenuation is com
pensated for.
_
3. In a radio receiver of the type comprising a
signal transmission tube and a single recti?er in
cascade, said transmission tube having‘ signal 45
carrier selector
resonant
networks
associated .
therewith which are suf?ciently sharp to produce
attenuation of the higher modulation signal fre
quencies, means in circuit with the recti?er pro-1
ducing a direct current voltage whose value va- 50
ries directly with the carrier amplitude, only a
single network for applying said voltage to the
transmission tube in a sense to reduce the gain
thereof, and the time constant of said last net
work being chosen su?iciently low so that the
2
2,129,078
gain of the transmission tube is less for low
modulation frequencies than for the aforesaid
higher modulation frequencies whereby the said
attenuation is compensated for, said recti?er act
ing as the demodulator of the receiver, said
recti?er being of the diode type.
4. In a receiver of side band modulated carrier
signals, an ampli?er for the signals, signal se
lector networks sufficiently sharp to cause side
10 band cutting, solely a single automatic gain con
trol circuit connected to decrease the ampli?er
gain in response to an increase in carrier ampli
tude at the selector network output, and said
control circuit having a time constant which is
chosen sui?ciently low to reduce the ampli?er
gain more for the lower modulation frequencies
of the side bands than for the higher modulation
frequencies thereby to compensate for the side
band cutting.
ERICH ZEPLER.
Документ
Категория
Без категории
Просмотров
0
Размер файла
200 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа