For CT viewers old enough to remember ch18 in hartford during the 1960's
One of the first pay tv stations in the country.
A c/p from wikipedia
The Phonevision system was operational on station WHCT in Hartford, Connecticut for at least two years, ending in 1969. The station would run conventional (non-subscription) programming during the day as an "independent," and then switch to Phonevision encoded programming in the evening. The system operated by switching a delay line in and out of the video, which chopped the picture into slats (like looking through an open venetian blind). Half of the slats would be shifted to the right by a significant amount. Decoding reversed the process and slid the other slats over the same amount, realigning the picture. The video information was also reversed in phase, exchanging black and white. The audio was processed by "frequency inversion scrambling," shifting the audio spectrum up 2.625 kHz in frequency. This produced audio that sounded much like single sideband radio except that only high frequencies were present. Decoding of the audio was done by a dual-conversion processor. The audio was first shifted up 31.5 kHz, and then shifted down 34.125 kHz, producing a net "downshift" of 2.625 kHz. 31.5 was double the horizontal sweep frequency of 15.750 kHz, and 34.125 kHz was 13/6 ths of 15.750, giving a convenient frequency reference. The frequency tolerance was so tight that if encoded audio were recorded during a Phonevision broadcast, and then played back later into a homemade processor running on normal network programming, a slight frequency error could be detected in the restored audio. Also, when the station switched to local sync to run a local commercial, the frequency change could be heard. One of the major limitations of the Phonevision system was that due to the delay line being switched in and out, color could not be broadcast, as the 3.58 MHz phase lock necessary for NTSC color broadcasting could not be held. This limitation contributed to the demise of the system, along with the FCC authorization of subscription programming about 1969.
I remember an Ali fight broadcast as what was later termed "PPV"
One of the first pay tv stations in the country.
A c/p from wikipedia
The Phonevision system was operational on station WHCT in Hartford, Connecticut for at least two years, ending in 1969. The station would run conventional (non-subscription) programming during the day as an "independent," and then switch to Phonevision encoded programming in the evening. The system operated by switching a delay line in and out of the video, which chopped the picture into slats (like looking through an open venetian blind). Half of the slats would be shifted to the right by a significant amount. Decoding reversed the process and slid the other slats over the same amount, realigning the picture. The video information was also reversed in phase, exchanging black and white. The audio was processed by "frequency inversion scrambling," shifting the audio spectrum up 2.625 kHz in frequency. This produced audio that sounded much like single sideband radio except that only high frequencies were present. Decoding of the audio was done by a dual-conversion processor. The audio was first shifted up 31.5 kHz, and then shifted down 34.125 kHz, producing a net "downshift" of 2.625 kHz. 31.5 was double the horizontal sweep frequency of 15.750 kHz, and 34.125 kHz was 13/6 ths of 15.750, giving a convenient frequency reference. The frequency tolerance was so tight that if encoded audio were recorded during a Phonevision broadcast, and then played back later into a homemade processor running on normal network programming, a slight frequency error could be detected in the restored audio. Also, when the station switched to local sync to run a local commercial, the frequency change could be heard. One of the major limitations of the Phonevision system was that due to the delay line being switched in and out, color could not be broadcast, as the 3.58 MHz phase lock necessary for NTSC color broadcasting could not be held. This limitation contributed to the demise of the system, along with the FCC authorization of subscription programming about 1969.
I remember an Ali fight broadcast as what was later termed "PPV"
