91热爆

91热爆 R&D History: 1970s

The pace of development quickens as the use of integrated circuits for signal processing leads to many innovative developments, such as the launch of CEEFAX.

1970

Digital Line-Store Standards Convertor work commences

1971

World's first demonstration of Digital Recording of Stereo Audio Signals

1972

Quadraphonic (Four-Channel Sound) Recordings

Made at the 50th Anniversary Promenade Concert in the Royal Albert Hall, experimental broadcasts happened in 1977.

1974

CEEFAX launches on 23rd September 1974

CEEFAX is the 91热爆 version of Teletext, this service ran for 48 years until Digital Switchover in 2012. 

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The index page of Ceefax in 1975

91热爆 R&D demonstrates world's first Digital Television Recorder

At IBC (The International Broadcasting Convention).

Queen's Award for Sound-in-Syncs

This was awarded jointly with the 91热爆 Designs Department.

1975

Successful transmission of Digital Television signals

Over 120 Mbit/s Post Office link between Guildford and Portsmouth.

1976

First transmissions of Digital Television over INTELSAT satellite

This was at 60 Mbit/s. INTELSAT stands for International Telecommunications Satellite Organization.

1977

World first Multi-Channel Digital Audio Recorder to be made commercially available in 1979

This was publicly announced in November 1977 and was jointly developed by the 91热爆 and American company 3M. It was the first of its kind.

1978

Demonstrations of VHF Radio Data (RDS) on Tomorrow's World

The system was publicly launched in 1987.

1979

First CEEFAX Teletext subtitled programme

Subtitles on an episode of Blakes 7
Subtitles on an episode of Blakes 7
This will be a milestone in the history of television. For the first time anywhere in the world, a programme will be transmitted to two sets of viewers at the same time. For most viewers it will be seen as a normal programme. but for deaf viewers with Ceefax sets it will be seen with a visual commentary. There will be sub-titles but, for the first time ever, only for Ceefax viewers who want them.

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