| 摘要 |
<p>PURPOSE:To enable processing by one circuit both signals of NTSC system and PAL system and to reduce the size of circuit scale by making the sampling frequency N-times of that of the horizontal synchronizing signal of the analogue video signal. CONSTITUTION:The composite video signal undergoes an A/D converter 2, and its frequency is converted by a converter 3. In the converter 3, the frequency is converted from 3.58MHz to 4.5MHz when recording and from 629kHz to 4.5MHz when reproducing, and at this time, the sampling frequency fS is made 18.00MHz provided that the fS is N-times (N is an integer) of the horizontal synchronizing signal of the analogue video signal where; when the integer N is divided by 4 to be N=4K+M (K is an integer, M is either one from 0-3) and is divided by 3 to be N=3L+Q (L is an integer, Q is either one of 0, +1, -1) then the P of P=M+Q is made an odd number. Of the converted signal, after the digital processing, the PS decoding processing of the chrominance signal is performed.</p> |
