| 摘要 |
PURPOSE:To correct the asymmetricalness of an FM output signal by using a differential amplifier, a limiter which gives the waveform shaping to the output of the differential amplifier, and an operational amplifier which converts the limiter output into a DC. CONSTITUTION:The reproduction FM signal which is picked up out of a video disk and amplified by an operational amplifier shunt open/close means is inputted to an input terminal of a differential amplifier 1 serving as a nonlinear amplifier. While the DC signal obtained from an operational amplifier 3 is inputted to the other input terminal of the amplifier 1. Then the output of the amplifier 1 is used for video processing at the next stage and also led to a limiter to undergo the waveform shaping. The signal thus obtained is converted into the DC corresponding to the secondary distortion via the amplifier 3. Thus the DC signal is inputted to the other input terminal of the amplifier 3. Then the amplifier 3 absorbs the secondary distortion by changing its follower center voltage. Thus the output of the amplifier 3 has the symmetricalness. |
