| 摘要 |
<p>PURPOSE:To reduce the scale of a circuit by restoring digitally pilot signals superposed on a digital modulation signal with a clock corresponding to a reproducing operating frequency. CONSTITUTION:An A/D converter 109 quantizes a reproduced modulation signal into a signal, for example, having 6 bits and the quantized signal is outputted to a terminal 115 as video data via a viterbi decoder 110 and a digital producing signal processing circuit 114. An ATF detection circuit 130 is provided with detection circuits 112, 113 corresponding respectively to the first and second pilot signals f1, f2 superposed in the digital modulation signal and detects and extracts pilot signals f1, f2 from the reproducing modulation signal of the A/D converter 109 to transmit them to an MPU 140 as signals such as a tracking control, etc. Detection circuits 112, 113 perform samplings with clocks based on the signal of a drum PG 15 as a decimate means. And, a squaring circuit for obtaining the absolute value of a control signal vector is used in common by being switched with a time phase.</p> |
