A digital TV codec system is designed and implemented for transmission of a broadcast quality color TV signal at the T3C rate of 90.194 Mb/s.
The sampling frequency of this system is 682 $f_H$, and the coding method is a simple 9 bit PCM with a horizontal blanking control.
The encoder removes the front porch and the horizontal synchronization pulse of the horizontal blanking interval from the composite TV signal. The video data is multiplexed with audio and line status data to form a transmission data frame synchronized with TV scan line. At the decoder, the different kinds of sync patterns are regenerated depending on the line status, and multiplexed with active video signal before being converted to analog signal. The expected SQNR is over 56 dB.
The system is implemented mostly with high speed ECL IC's. It is found from experimental results that the codec system can be employed for practical digital transmission of broadcast color TV signals.
