| 摘要 |
PURPOSE:To automatically and securely decide a recording mode by extracting the DC level in a sink chip level transmission period from a reproducing video signal and comparing it with a reference level for decision making. CONSTITUTION:A reproducing video signal passed through an FM demodulator 2 and an LPF 3 is supplied to a sample holding circuit 4 and a synchronizing signal separating circuit 5. A horizontal synchronizing signal outputted by the circuit 5 is used as sampling pulses by the circuit 4 to extracts the DC level in a sink chip level transmission period which varies according to the recording mode from the luminance signal of a video signal, and the DC level is supplied to a comparing circuit 6 supplied with the reference level. Then, the circuit 6 outputs the comparison output of the recording mode decision result to securely and automatically decide the recording mode.
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