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November 1969 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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Lots was happening in
the electronics realm when this "New & Timely" collection of items appeared in
the November 1969 issue of Radio-Electronics magazine. It was the eve
of a new decade, following a decade of great social and military upheaval.
Brushless motors, nowadays probably more common than traditional brushed motors
in consumer electronics, were a relatively new phenomenon in electronics.
Reducing integrated circuit (IC) mask feature sizes by using short wavelength
(x-ray) electron beams was replacing visible wavelength beams. Thanks to the
proliferation of microcircuits, digital clocks either directly using or
referencing atomic clocks were quickly moving from the laboratory into
commercial applications. The ongoing saga of
x-ray emissions
from color TV high voltage power supplies resulted in new government
regulations limiting dosage. Big Brother prohibited the sale of
SCA (Broadcast
Radio Subcarriers) receivers supposedly to safeguard the financial concerns of
commercial broadcasters (one of the first bans on receiving electromagnetic
signals, followed by some states banning police radar detectors).
New & Timely
 Atomic
Clock for EXPO '70
Osaka, Japan - Visitors to Japan's world fair, Expo '70, will be sure of
having the right time handy. Some 110 standard and digital clocks throughout the
fairgrounds are being equipped with uhf receivers. An atomic-regulated master
clock installed in a time center (see drawing) will transmit super accurate time
signals to the receivers operating with each clock. The master clock uses a
crystal oscillator system that is in turn regulated by an atomic frequency
standard. The system is designed to vary in accuracy by only one or two seconds
in several thousand years. Seiko of Japan, a watch manufacturer and official
time keeper for the world exposition, is preparing the system.
Brushless Motor
Tokyo - Use of the Hall effect for a brushless dc motor has been announced by
Pioneer Electronic Corp. for portable and car tape recorders. The motors, which
do not need commutators or brushes, reportedly provide noise free operation with
very low rumble, wow and flutter.
With the Hall effect, a voltage is developed across a conductive material when
it is placed in a vertical magnetic field. Pioneer uses IC's in conjunction with
the Hall device to electronically operate the motor.
 Electron Beams Reduce IC Size
Pittsburgh - A new technique that uses electron beams instead of light to
make integrated circuits can make possible "the next generation of miniaturized
electronic circuitry," according to Westinghouse.
With the technique, some 4 million three-element electronic devices can be squeezed
onto a postage stamp size area. A Westinghouse scientist said circuit components
100 times smaller than those available for large-scale integration IC's today will
be possible.
To make the masks used to fabricate the LSI wafers, the drawings are digitized
and put on magnetic tape. A computer then uses the information to control a scanning
electron microscope, which traces an exact-size mask pattern into a sensitized metal
plate. The stencil-like, light-sensitive masks are then placed one after another
at the cathode of an image tube. When light is shined on the masks they eject electrons
toward the anode of the tube. A sensitized silicon wafer at the anode records the
pattern of each mask.
The photo shows a TV display of one of the masks used to form the LSI circuit
on the wafer being held.
New X-Ray Standards Set for Color TV
Washington - A gradual tightening of standards to cut X-ray emission from color
TV was approved by a Department of Health, Education and Welfare technical committee
in August.
According to the three-part proposal, by January 1970, sets must be built so
that radiation does not exceed 0.5 milliroentgens per hour about 2 inches from any
point when power supply voltages exceed normal levels. By June 1970, this 0.5 mR
could not be exceeded even if viewers tried to readjust controls.
Finally, effective in 1971, the new rules call for limiting X-radiation
to below the 0.5 mR level even if the set malfunctions.
Looking Ahead: SCA Receiver Ban
The FCC, in a surprise action, has banned the sale of SCA (multiplex) receivers
by a retail and mail-order chain to general consumers. Armed with a Justice Department
opinion, the Commission obtained agreement by Lafayette Radio to stop selling radios
designed to receive Subsidiary Communications background music sub carrier transmissions.
The Justice Department said that unauthorized use of private transmissions was illegal
when the listener derives a "gain" from it - the "gain" in this case presumably
being enjoyment of music. Previous FCC advisory opinions had indicated that the
Commission saw no law violation in consumer reception of SCA transmissions.
FM Dominates Radio
The dream that frequency modulation some day would be the dominant force in radio
has finally been realized. For the first time in history, Americans are buying more
FM-equipped than AM-only radios. In this year's second quarter, the cross-over became
apparent. Of 8.9 million table, clock and portable radios sold in the United States,
4.6 million (or 51.9%) had FM.
Thus the common garden variety home and portable radio has now joined the more
sophisticated component tuner and the radio-phonograph or TV combination in converting
to FM. The only radio field which is still a virtual AM monopoly is auto radio -
but even this is gradually changing. In 1968, about 11% of car radios sold had FM.
The share inched up to 13% in the first half of this year.
Government X-Ray Standards
Agreement has been reached between the government's Bureau of Radiological Health
and a government-industry-public advisory committee on standards for radiation for
color for sets, involving a progressive tightening of permissible limits. As of
next Jan. 1, no receiver may radiate more than 0.5 rnilliroentgens per hour (mR/hr.)
as measured at 5 centimeters (about 2 inches) from any surface of the outside of
the set with line voltage at 130 and all user controls set for maximum radiation
.
Beginning June 1, the same limits will apply, but with service controls set so
as to produce maximum radiation. And, as of June 1,1971, the 0.5-mR limit will be
enforced with receivers doctored to simulate failure of components or circuits (shunt
regulator, etc.) to increase radiation. Television set manufacturers, now concentrating
on introducing such fail-safe components as solid-state high-voltage rectifiers,
feel that they can meet this schedule.
The next X-ray standard to be propounded by the Bureau is expected to set limit
on radiation of receivers during servicing, for the protection of technicians. R-E
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