| 摘要 |
PURPOSE:To prevent side band components from being superposed on the base band component at an FM demodulation time by converting the frequency of an FM signal to a frequency area higher than the FM frequency and applying frequency demodulation to this FM signal to obtain a modulated signal. CONSTITUTION:A carrier signal fA whose frequency is sufficiently higher than the maximum frequency of a luminance signal Y is applied with frequency modulation by the luminance signal Y in an FM modulator 12 of an FM modulating circuit 10, and higher side bands are suppressed by a BPF13, and the output has the frequency converted by a carrier signal fB from an oscillator 15 in a balanced modulator 14, and thereafter, an FM signal SY.FM which has the frequency converted to the low band side by an LPF16 is extracted. The signal SY.FM recorded in this manner is reproduced and passes a terminal 31 and has the amplitude limited to a certain value by a limiter 32 and has the frequency converted by a carrier signal fD having a sufficiently high frequency in a frequency converter 33, and a high band converted FM signal SYH is extracted by a BPF35, and this signal passes a limiter 36 and is demodulated to a signal Y by an FM demodulator 37.
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