| 摘要 |
<p>PURPOSE:To allow a digital comb-line filter to separate a luminance signal component and a color difference signal one by alternately repeating the level inversion and non level inversion of a luminance signal component at every horizontal scan period and transmitting it. CONSTITUTION:A signal reproduced by a recording and reproducing device 15 is FM-demodulated by an FM demodulator circuit 16. An unnecessary high frequency component arising at the time of FM demodulation is removed by a low-pass filter 17, AD-converted by an AD converter 18 and supplied to the digital comb-line filter 19. When it comes to a signal whose luminance signal component is level-inverted at every 1H, the frequencies of an inverted luminance signal and uninverted one employ fH/2 (fH: one horizontal scan frequency) as basic frequencies. Thus a video signal is constructed of fH, 2fH, 3fH... frequency components and fH/2, 3fH/2, 5fH/2... frequency components (odd-degree high frequency components). Accordingly the digital comb-line filter 19 can clearly separate color difference signal components C at frequencies fH, 2fH, 3fH... and luminance signal components Y at frequencies fH/2, 3fH/2, 5fH/2....</p> |
