| 摘要 |
<p>PURPOSE:To attain the detection of the program searching of a first music, by detecting the end of a period where no recording signal exists by an envelope detection circuit, after detecting a bit of sub-code information by a sub-code detection circuit, and detecting the start position of a music. CONSTITUTION:The output of a reproducing amplifier 6 detects a start ID signal through a sub-code extraction circuit 11, and a start ID signal extraction circuit 12, etc., and is supplied to a microcomputer 14. Meanwhile, an envelope detection circuit 13 envelope-detects the output signal of the reproducing amplifier 6, and also, supplies a signal to the computer 14 only for a period where no recording of a digital signal is performed on a magnetic tape 2. The output of the reproducing amplifier 6 is processed at the envelope detection circuit 13, and is changed to a signal having a waveform which goes to an 'L' level only for a period where no recording signal exists, and it is supplied to the computer 14, and after detecting the start ID signal, it detects the trailing edge of the output signal from the envelope signal detection circuit 13. In this way, a control signal is outputted to a mechanism control circuit 15, then the program searching of the first music can be performed.</p> |
