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April 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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The title of
Radio-Electronics magazine's breaking technical news column changed over
the years, including "News Briefs," and this one from the April 1969 issue, "New
& Timely." A lot of major science breakthroughs in materials, components,
systems, projects, regulations, and personality news happened between each
month's selected items. This month featured topics like digital TV transmission
standards, new RFI rules from the FCC, the high number of electrocutions
occurring in hospitals due to faulty wiring, a camera was developed for NASA
moon missions, licensing of electronics repairmen, and the increasing number of
integrated circuits (ICs) being designed into consumer products was on the rise.
Read on...
New & Timely Technical News
 Digital
TV Transmission Developed
London - British Broadcasting Corp. engineers have developed equipment that
enables TV signals to be transmitted with digital techniques. The method, called
pulse code modulation (PCM), samples a video signal at regular intervals and
converts the sample into pulses that represent a binary code. PCM techniques
have been adopted for data trans-mission over telephone lines in this country.
The BBC system being studied samples a 625-line, 5.5-MHz TV signal
approximately 13 million times a second. The bit rate, or number of pulses per
sample, must be seven or eight bits for high-quality pictures. Proto-type
equipment using six bits permits 64 brightness levels, which is sufficient
except for certain scenes. The BBC converter shown in the diagram is a
series-parallel design in which the three most significant digits are extracted
by a parallel converter, and the three least significant digits by another
converter in series with the first. Before being sent to the second converter,
the three most significant digits are reconverted to analogue form and
subtracted from the original signal. Chief advantage of PCM for TV transmission
is its immunity to small signal changes that can raise havoc with complex color
signals. With PCM, pulse shape can vary considerably before be-coming
unrecognizable at the receiving end. The system was described in the magazine
Electronics Australia.
FCC Plans RFI Rule Revisions
Washington, D.C. - The boom in consumer and industrial devices that generate
radio-frequency interference (RFI) has a prompted Federal legislation authorizing
the FCC to regulate the manufacture, import, sale, shipment or use of any potential
RFI devices. Earlier Federal regulations restricted the FCC only to control of radio-frequency
equipment use. The proposed FCC rules, which will influence companies previously
unaffected by Federal regulations, require type approval, acceptance or certification
prior to the sale or shipment of rf devices.
1200 Electrocutions in Hospitals Annually
Electronic and electrical instrumentation in hospitals helps save thousands of
lives daily, but a recent computer study by a major insurance company has revealed
it also takes some 1200 lives each year in the US through accidental electrocutions.
The figures, attributed to Dr. Carl W. Walter, a Boston surgeon, were reported
at a recent meeting on reliability and medical instrumentation. The majority of
the hospital patients killed were undergoing routine diagnostic test or treatment.
As reported in an issue of Electronic News, the causes of hospital accidental
electrocutions appear to be growing in complexity as the instrumentation use increases.
A major problem is linking incompatible instruments simultaneously to a patient,
creating an ac current loop that causes fibrillation - erratic beating - of the
heart. Poor circuit design contributes to dangerously high leakage current from
some equipment on the market and the problem is compounded by untrained hospital
personnel who "wire" patients into a ground loop easily completed when a faucet
or other equipment is touched.
Approval by Underwriters Laboratory is not a requirement for hospital instrumentation,
the Electronic News report noted. Companies are increasing safety by using isolation
transformers self-destruct fusing device and separate-ground three-wire power cables.
 Lunar TV Camera
Baltimore, MD. - This TV camera is going to the moon with the Apollo astronauts.
It's one of 17 built for NASA by Westinghouse, and uses a secondary electron conduction
(SEC) imaging tube for extreme low-light sensitivity. A cable from the spacecraft
provides the 6 1/2 watts of power needed. Camera can "see" scenes invisible to the
human eye, yet will not bloom when exposed to extremely brilliant images. Integrated
circuits are used extensively.
Repair License Bills
Legislation that would require licensing of TV service techs is being introduced
in the State Legislatures of New York and Pennsylvania. The New York bill would
establish an advisory board to set license requirements and standards. Similar legislation
sponsored by a Pennsylvania service association would additionally require service
technicians to provide a statement showing all parts placed in a set, an itemized
list of all charges, and name and address of repairer.
Looking Ahead
IC's in Consumer Products
The number of active integrated-circuit elements used in consumer electronic
products - television, radio, phonographs, tape recorders, etc. - will exceed receiving
tubes by 1971, and discrete semiconductors by 1975. That's the projection of Motorola
Semiconductor Products. Motorola says 78% of all active components in consumer electronic
products built this year will be discrete semiconductors, while 18% will be tubes
and4% will be IC's. Discrete semiconductors' share will remain at 78% in 1970, Motorola
forecasters think, but IC's will gather a 9% share at the expense of tubes, which
will decline to 13%.
They Still Watch
You may think people have given up on television, but it's just not true. Analyzing
rating surveys, the Television Bureau of Advertising has found that the average
family watched more television than ever in 1968 - 5 hours and 48 minutes per week,
or 6 more minutes a week then in 1967. The study credited new color sets for much
of the increase.
Meanwhile, color has passed something of a landmark. As 1969 started, the NBC
research department reported that almost one-third of all television-equipped households
- 19.2 million of them - had color sets. The total number of color sets as of Jan,
1 was about 20.1 million. The number of sets is higher than the number of color
households because some homes have two color sets, and some sets are in hotels,
bars, offices, etc.
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