| 摘要 |
PURPOSE:To improve the S/N and also to prevent the deterioration of picture quality to ensure a descramble system of high stability, by giving the frequency characteristics to the modulation degree with a descramble logarithm modulating circuit. CONSTITUTION:An AM component of a sound signal is applied to a sound signal AM wave detection circuit 8 from the output of a logarithm modulating circuit 10 and fed back to the circuit 10 via a band amplifier 9. Thus the descramble is carried out. Here the frequency characteristics are given to the modulation degree through the circuit 10. In other word, the modulation degree of the sound frequency is set smaller than other frequencies. In such a way, the S/N is improved and the deterioration of picture quality can be prevented. This secures the descramble with high stability. |
