| 摘要 |
PURPOSE:To realize stableness of operations and simplification of the circuit, by detecting drop-out after converting the FM luminance signal to a low frequency. CONSTITUTION:The signal from video head 11 becomes a luminance signal through amplifier 12, BPF13, equalizer 14, amplitude limiter 21, and FM demodulator 22. In case of drop-out, switch circuit 15 is switched by the pulse from drop-out pulse generator 19, and the output signal from equalizer 14 is broken, and the output of 1H delay circuit 20 is caused to pass, thereby compensating the signal for drop-out. The circuit consisting of oscillator 16, mixer 17, and BPF18 converts (beats down) the carrier of the FM liminance signal to a low frequency temporarily, and only carrier components of the beated-down FM luminance signal are led to drop-out generator 19. As a result, stable and sure operations are possible. |
