Apparatus for processing BPSK signals transmitted with NTSC TV on quadrature-phase video carrier
US5448299A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 5, 1994 |
| Grant date | Sep 5, 1995 |
| Priority date | — |
| Expiry date | Jan 5, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/426
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A vestigial-sideband amplitude-modulation transmitter using a balanced modulator for generating a suppressed carrier that is in quadrature phasing with the video carrier of a television signal receives as modulating signal a binary phase-shift-keying (BPSK) signal encoding digital signals. The quadrature transmission reduces the visibility of the lower-frequency PSK sidebands in the TV signal as viewed on screen. The symbol rate of the PSK is made to be a multiple of the horizontal line scan rate of video signal. To reduce the visibility of the higher-frequency PSK sidebands in the TV signal as viewed on screen, the BPSK is transmitted twice during respective frames of successive pairs of data frames, which data frames recur at the same rate as video frames. To reduce the interference of video with the BPSK, the BPSK is comb filtered at the digital signal receiver and after symbol detection is subjected to partial-response filtering for recovering the digital signal originally encoded in the BPSK signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.