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Online Exhibit:
History of Broadcast Technology :
1945 to Present
by David L. Morton, Ph.D.
| Introduction
In 1999, the IEEE Broadcast Technology
Society celebrated its 50th anniversary. The second oldest technical
society (the group that became today's Signal Processing Society
is slightly older) has a history that stretches to the formation
of the Institute of Radio Engineers in 1912. This exhibit highlights
just a few of the many accomplishments of broadcast engineers. Sponsored
by the IEEE Broadcast Technology Society and the IEEE History Center.
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The Society: Radio Engineers
and the IRE
The engineers who formed the core of the
original Institute of Radio Engineers in the 1920s and 1930s were
mostly from the broadcast industry. For about the first 30 years
of its existence, "radio" was virtually synonymous with "broadcasting."
But the years after World War II brought drastic changes to the
field of electrical engineering. Electrical technology was moving
rapidly; radar, computers, television, solid-state electronics,
and space exploration were burgeoning fields.
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| After World War II
The effect of the war could be seen in
the membership of the IRE, which grew from 5,200 in 1940 to more
than 18,000 by 1946. Membership continued to climb rapidly during
the 1950s, finally surpassing the rival AIEE's membership in 1957,
when total IRE membership, including students, reached 64,773. Students
represented a fifth of that total, and the accelerating growth of
the IRE's student membership was evidence of a society that was
successfully riding the wave of a technological revolution.
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The Merger
By the early 1960s, the IRE and the AIEE
were discussing the possibility of merging, and on 1 January 1963
that union was accomplished when the IEEE was officially born. The
new organization continued the IRE's structure of Professional Groups
representing particular technical interests. This plan had been
proposed in 1945 in response to the fear that audio engineers might
form their own organization separate from the IRE (which they eventually
did despite the formation of an IRE Audio Group in 1948).
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From Professional Group to Society
The second of the new Professional Groups,
authorized in 1948, was the Broadcast Engineers Group. From the
first meeting of the group in 1949 to 1976, the Broadcast Engineers
Group was not concerned with broadcast receivers, but in 1975 merged
with the Consumer Electronics Group (formerly known as the Group
on Broadcast and Television Receivers). There were other name changes
before AIEE/IRE merger in 1963. The IEEE Professional Technical
Group on Broadcasting, as it was called after 1963 absorbed the
Committee on Video Techniques and the Television systems Committee
in 1967 but was merged into the IEEE Broadcast, Cable, and Consumer
Electronics Society following the re-organization of the Institute
into Technical Societies. Then, in 1982, the Society assumed its
current form when the Consumer Electronics society was made independent.
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Radio
Radio broadcasting emerged in the first
decade of the 20th century and flowered in the United States and
Europe during the 1920s. By the 1930s, virtually every country in
the world had a network of radio stations and broadcasting engineers
were in demand. The World War II years saw a considerable expansion
in the use of broadcasting, as the U.S. and other nations established
new networks to serve the entertainment and information needs of
the military.
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Postwar Broadcasting
By the time the BTS held its first meeting
in 1949, radio broadcasting was undergoing important changes. Commercial
AM network broadcasting reached a peak soon after the end of World
War II. The broadcasting field in the late 1940s was
clearly ripe for change. IRE (and later IEEE) engineers contributed
to the reconstruction of broadcasting, designing new technologies
that lowered costs and allowed local stations to produce their own
programs. These innovations included station automation and studio
equipment that allowed stations to run virtually unattended. Stations
became less dependent on live programs, turning instead to recorded
programs.
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Postwar Technologies
A major innovation of the postwar period
was the magnetic tape recorder, which could be used to record and
reproduce programs of almost any length, and could be set to run
automatically. The Ampex and Magnecord Corporations developed a
variety of recorders that became standard equipment in broadcast
studios by the early 1950s. Broadcasting engineers also innovated
an entirely new radio medium called Frequency Modulation. First
proposed in its modern form by IRE member Edwin H. Armstrong, FM
promised higher quality sound and virtually no interference. But
despite initial enthusiasm for the new technology FM took hold slowly
in the United States (it had somewhat more success in Europe). In
fact, most FM broadcasters did not show a profit until the 1970s.
FM broadcasting was the subject of considerable experimentation,
as engineers looked for ways to enhance its appeal.
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From Elevator Music to Quadraphonic Stereo
Single-sideband, for example, allowed beleaguered
station owners to transmit fax messages, "background" music services,
or other information on unused sidebands. Stereophonic broadcasting
became widespread by the 1960s and eventually proved highly popular,
but quadraphonic FM broadcasting won almost no fans. By continually
striving for improvement, engineers found ways to make radio broadcasting
a profitable medium in the face of competition from TV. Radio broadcasting
has actually expanded since 1949; in that year there were about
2600 radio stations in the U.S., while there were almost 10,000
in operation fifty years later.
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Television
Regular television broadcasts began in
1936 in England and France and 1939 in the United States, but World
War II delayed its widespread adoption. After a brief lag in 1946
and 1947 due to reconversion to civilian production, television
receiver sales took off in 1948 and 35 million U.S. families had
a TV by 1955. Only five countries had television service in 1950,
but that number had risen to 138 in 1980, when there were an estimated
400 million sets in use. Broadcast engineers contributed fundamentally
to the establishment and upgrading of TV service around the world.
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Standards, Standards, Standards
Of the many pressing technical issues facing
engineers was the establishment of broadcast standards. Engineers
in different countries argued for different standards for such things
as the number of lines on the screen. The United States and much
of Europe went for a system sponsored by RCA (the European system
was slightly modified for 50 Hz power), while France and Great Britain
developed their own standards. A considerable amount of engineering
effort went into problems related to interference between stations
and the limited number of available channels. In 1953 the UHF band
was opened for television broadcasting, but it became a "second
class" band in part because of the way television receivers were
designed. More successful in solving program distribution problems
was cable distribution.
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Cable TV
Zenith Corporation offered a simple type
of subscription television service in 1951, but the development
of coaxial cable distribution opened the door to the adoption of
cable distribution in the 1960s and 1970s. Cable saw its greatest
success in the U.S., where there were over 26 million subscribers
by the early 1980s.
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In Living Color!
One major development affecting television
cameras, video recorders, processing equipment, and receivers was
the appearance of color. The FCC authorized color broadcasts in
the U.S. in 1950, using the "color wheel" system of CBS. Later,
the FCC reversed its decision and standardized the all-electronic
color system developed by RCA, which was compatible with monochrome
receivers. This backwards compatibility was a wise choice, as it
turned out, because the number of color receivers in use was quite
low until the late 1960s.
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Satellites and HDTV
From the 1970s to the present, broadcast
engineers contributed to the development of satellite distribution.
Many different systems were proposed or built, including the early
satellite-based, High Definition Television system in Japan, direct
satellite broadcasting for remote areas such as Alaska or the African
continent, and the more recent DBS consumer satellite broadcast
system. High Definition Terrestrial Digital Television is being
implemented throughout the world. Digital Television stations are
going on the air in the United States and will run concurrent with
NTSC stations until the build-out period has been completed.
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