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February 1963 Radio-Electronics
 [Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Electronics,
published 1930-1988. All copyrights hereby acknowledged.
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News Briefs
Telstar Refuses To Take Orders
The Bell Telstar satellite, after four months of successful operation, developed
trouble in the system which turns its communications receiver and transmitter on
and off, making it impossible to use it as a radio and television relay. The telemetry
circuits were at last reports still working perfectly, sending back reports on the
amount of radiation in space, the condition of the satellite and its components,
temperature readings, effects of radiation on the solar cells and transistors -
in fact, almost everything except why the command circuit won't work.
100 Conversations Carried On Single Telephone Path
A new British electronic telephone exchange permits subscribers to carryon perfect
telephone conversations, though they are connected to the line only 1% of the time.
The principle is called "time division multiplex," and consists of a crystal-controlled
switching system operating at 1 mc. Each of 100 telephone lines is gated "on" with
a semiconductor diode 10,000 times per second, and a 1-microsecond sample of each
caller's voice is taken and transmitted down the line. A similar switching device
at the other end picks up the 1-μsec sample and routes each to its proper circuit.
Engineer inserting information into the magnetic memory of the exchange.
Since 10,000 samples are taken per second, the listener at the other end of the
line cannot hear any noticeable difference from "solid" conversation, even though
a single syllable may have been broken into hundreds of pulses. Speech quality,
in fact, is stated to be considerably higher than required for ordinary telephone
work, with a flat response from 300 to 4,200 cycles per second.
The new exchange is also completely automatic, with a magnetic memory storing
all the information relating to each line and recording the number and duration
of each call. It accepts calls from one subscriber and routes them through, calling
on other sections of the memory for the correct instructions to make the connection.
The 800-phone exchange acts as if it had only one operator handling all the calls
one at a time, but an operator working so rapidly that the subscriber can detect
no delay in the completion of his call.
FCC Adopts Uhf Rules
The technical standards for uhf TV receivers recommended by the manufacturers
last summer (Radio-Electronics, September, 1962, page 6) have been adopted by the
FCC without notable changes. All sets shipped in interstate commerce after April
30, 1964, must be equipped to receive all channels. Sensitivity of the uhf channels
is to be not more than 8 db below the average of the sensitivity of the vhf channels.
A request has been made to the FCC for a special ruling to cover equipment used
in schools, hospitals, hotels, and similar community antenna type systems, where
the signal is received on uhf but converted to vhf for cable distribution to the
receivers. In such cases there would be no point in having uhf channels.
Niels Bohr Dies
Prof. Niels Bohr, world-renowned atomic physicist, died Nov. 18. In 1913, Prof.
Bohr discovered the role of the quantum in the structure of the atom, launching
a life-long study that paved the way for present-day knowledge of the atomic nucleus.
In 1922, Professor Bohr received the Nobel Prize in physics for "studies on the
structure of atoms and the radiation emanating from them." He is responsible for
the founding of the Institute of Theoretical Physics in Copenhagen.
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