| 摘要 |
PURPOSE:To perform excellent FM demodulation free of inversion by discriminating the carrier frequency of an FM signal and controlling the limit of a demodulation frequency on the basis of the discrimination output. CONSTITUTION:An FM luminance signal from a head 1 is led out through a regenerative amplifier 2 and supplied to an FM demodulator 4 through a limiter 3. This FM luminance signal is led to a band-pass filter 5 to limit its band on the upper and lower sides and then supplied to an FM demodulator 7 through a limiter 6. The demodulation frequency limit of the FM demodulator 4 is controlled according to the signal from this FM demodulator 7. Further, the output of the demodulator 4 is supplied to a variable gain amplifier 8 and the signal from the demodulator 7 is supplied to the control terminal of an amplifier 8, so that a gain-controlled luminance signal appears at an output terminal 9. |
