| 摘要 |
PURPOSE:To avoid the production of overmodulation after demodulation, by discriminating the phase of FM modulated luminance signal at the supply of dropout detection signal and selecting an output signal with minimum switching phase error for the switching with this signal. CONSTITUTION:A luminance signal S0 to be frequency-modulated is applied to an input terminal 1, this signal is applied to a limiter 3 via a delay line 2 and a delay line 4 having amount of delay by nH's share, and a plurality of phase conversion signals S1-S4 with different phase are obtained at a phase conversion circuit 5. The output of the circuit 5 is given to a switching circuit 15 via switching circuits 13, 14, and an output signal Sc out of the signals S1-S4 is applied to a switching circuit 10 from the circuit 15 to output 11 the signal S0 or the Sc. A dropout detection signal is applied to a control circuit 23, then the phase of the signal S0 is discriminated at 17 to select the output signal Sc with minimum switching phase error for the switching with the signal S0 at a signal selection circuit 12. |
