SINGLE-CHANNEL TELEVISION RECEIVER

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00809A000600390233-0
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 3
• Document Creation Date: December 22, 2016
• Document Release Date: October 19, 2011
• Sequence Number: 233
• Publication Date: May 9, 1951
• Content Type: REPORT

Sanitized Copy Approved for Release 2011/10/19: CIA-RDP80-00809A000600390233-0
CLASSIFICATION CONFIDENTIAL
CENTRAL INTELLIGENCE AGENCY REPORT
INFORMATION FROM
FOREIGN DOCUMENTS OR RADIO BROADCASTS
SUBJECT
HOW
PUBLISHED
WHERE
PUBLISHED
DATE
PUBLISHED
LANGUAGE
Scientific - Radio, television receiver
Monthly periodical
Moscow
Sep 1950
THIS DOCUMENT CJNTAINS INFORMATION AFFECTING THE NATIONAL DEFENSE
OF THE UNITED STATES WITHIN TOE MEANING OF ESPIONAGE ACT 10
U. S. C.. 11 AND 11. AS AMENDED. 'IS TRANSMISSION OR THE REVELATION
..F ITS CONTENTS IN ANT MANNER 10 AN UNAUTIIORIIED PERSON IS PRO
NIEITED by LAW. R[PRO Ouli IN OF THIS FORM IS PROHIBITED.
Radic, No 9, ).950, pp 46-48
CD NO.
DATE OF
NO. OF PAGES g
SUPPLEMENT TO
REPORT NO.
SINGLE-CILKNNLL TELEVISION RECEIVER
`Figures referred to are appended
Television receivers using straight amplification are becoming more and
more popular with radio amateurs. The rf amplification stages of these re-
ceivers are also used to amplify the accompanying sound signals. A block
diagram of a receiver of this type is shown in Figure 1. The amplitude-modu-
lated picture signal and the frequency-modulated sound signal are applied to
the input of the zf amplifier. The frequency response of this amplifier is
93mosL linear over the full range of frequencies (6.5 Mc), between the picture
signal carrier frequency of 49.75 Mc and the sound Larrier frequency of 56.25 Mc.
From the rf amplifier output, the signal is fed to the diode detector.
The detector load separates not only the picture signal voltage but also the
beat. frequency, equal to the difference between the picture and sound carrier
frequencies, or 6:5 Mc. Since the sound carrier is frequency modulated, the
beat frequency is also frequency modulated.
Thus, drawing an analogy with a superheterodyne, the carrier frequency
of the picture ei3nal transmitter here is similar to the oscillator frequen-
cy, while the intermediate frequency of the sound channel corresponds to the
beat frequency.
The signals are amplified further in the video amplifier. From the plate
of the output stage, the signal is applied to the cathode-ray tube and the in-
put of the if amplifier, which is tuned to the neat frequency.
The amplitude of the sound carrier frequency is suppressed strongly in
the rf amplifier, and thus the sound does not cause picture interference.
I
CLASSIFICATION CONFIDENTIAL
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CONFIDENTIAL
Figure 1. Block Diagram of the Asceiver
From the i-f amplifier, the signal is fed to the discriminator, converted
to audio frequency, and amplified by the of amplifier.
The schematic diagram of the receiver in Figure 2 corresponds to the
block diagrap. Tha first three 6AC7e are the rf amplifier stages. Contrast
is controlled by changing the grid bias of the second 6AC7. A blocking cir-
cuit (L10i C33) is provided to reduce the sound signal level. A 636 is used
as the diode detector. A 6A07 IN used for the output stage, and provision is
made for frequency correction (the chokes Dr2 and Dr3).
From the plate of the 6Aa7, the signal is applied through the capacitor
C1.3 (3Aetd) to the 6AC7 coil 16, which is tuned to the beat frequency. This
6AC7 is the i-f amplifier and the discriminator is in its plate circuit.
The "partial" ffati) detector NO-1 (described in Radio, No 6, 1949) used
in the receiver eliminates the need for a limiter. The second 636 is used as
a discriminator and is tuned to an average frequency of 6.5 me. F.-om the
discriminator output, the signal io fed to the audio amplifier, in which a
6637 and a 6F6 are employed. The volume and tone controls (resistors R21 and
R are in this amplifier.
27)
Theireceiver is very simple in construction (all the coils and chokes
can be ride at home) and at the r:= time provides better television recep-
tion than a superheterodyne receiver with Sever tubes. If the receiver is to
.be used 20-30 kilometers from the television center, another rf amplifier
stage should be added.
Xppended figures follow
CONFIDENTIAL'
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CUNFIDENTIMR.
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