| 摘要 |
PURPOSE:To attain the discrimination of a recording mode, by detecting the carrier frequency of a reproducing video signal to be frequency-modulated obtained by the reproduction of a recording medium. CONSTITUTION:An FM luminance signal reproduced from a magnetic tape is supplied to BPFs 2 and 3 through an input terminal 1. The BPF2 is a filter circuit in which the carrier frequency equivalent to a pedestal level in a standard mode is set as a passing center frequency, and the BPF3 is the filter circuit having a narrow band characteristic in which the carrier frequency equivalent to the pedestal level in a high picture quality mode is set as the passing center frequency. Each of the output signals of the BPFs 2 and 3 is supplied to LPFs 6 and 7 respectively through rectifier and peak holding circuits 4 and 5. Envelope detecting signals outputted from the LPFs 6 and 7 are sent to a comparator 8, and are compared with the first logic level at a standard mode time, and with the second logic mode at a high picture quality time, then a mode discriminating signal is outputted.
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