| 摘要 |
PURPOSE:To attain the discrimination of a recording mode, by detecting a carrier frequency equivalent to a pedestal level in both, or either of the horizon tal blanking signal period, and the vertical blanking signal period of a reproduc ing video signal to be frequency-modulated. CONSTITUTION:An FM luminance signal reproduced from a magnetic tape is supplied to BPFs 2 and 3, and a demodulation circuit 4 through an input terminal 1. Each of the BPFs 2 and 3 sets the carrier frequency equivalent to the pedestal level of a standard mode, or a high picture quality mode as a center frequency. The outputs of the BPFs 2 and 3 are envelope detected at detection circuits 5 and 6, and sample-held at sampling hold S/H circuits 7 and 8. Meanwhile, the demodulation circuit 4 consists of FM demodulation circuits of the standard mode, and the high picture quality, and outputs a reproducing luminance signal by switching them. The reproducing luminance signal is supplied to a sampling pulse generation circuit 10, and sampling pulses of prescribed levels are generated in horizontal and vertical blanking periods.
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