CONTROL DATA MODULATION SYSTEM, CONTROL DATA DEMODULATION SYSTEM AND VIDEO SIGNAL PROCESSING UNIT

摘要

PROBLEM TO BE SOLVED: To facilitate modulation and demodulation of a video ID signal between a digital device in compliance with the studio standards and a digital VTR adopting an HD format by selecting a frequency used for modulating control data to be a specific clock frequency synchronously with a frequency of a high definition television signal. SOLUTION: The sampling frequency in the HD format is 40.5 MHZ synchronously with a horizontal synchronizing signal. In the studio standards. the sampling frequency is 74.25 MHz synchronously with the horizontal synchronizing signal. Then a modulation frequency of control data adopts a clock frequency that is 1/N division (N is an interger being 2 or over) of 6. 75 MHz being a common divisor of the sampling frequency of the studio standards and the sampling frequency of the HD format. Thus, even when a received clock signal is the HD format or the studio standards, a control data modulation circuit frequency-divides the sampling frequency and uses the result for modulation.