PRE-FRAME-COMB AS WELL AS PRE-LIME-COMB PARTIAL-RESPONSE FILITERING OF BPSK BURIED IN A TV SIGNAL

摘要

BPSK modulation of suppressed carrier in quadrature with a video carrier amplitude-modulated by composite video signal is used for transmitting a serial-bit digital signal, which is subjected both to "pre-line-comb" and "pre-frame-comb" partial-response filtering prior to conversion to BPSK modulating signal. The "pre-frame-comb" partial-response filtering of the serial-bit data is done on a continuous basis, rather than transmitting frames of the BPSK twice, once in positive logic and once in negative logic, during successive pairs of consecutive frames of the NTSC television signal. This results in the full luminance bandwidth below chroma frequencies being available on average for the transmission of BPSK, rather than half that bandwidth.