| 摘要 |
PURPOSE:To read correctly a prescribed signal even at the time of highly speedy retrieving by generating a pulse such as a sub-code signal corresponding to the period of a head switching pulse. CONSTITUTION:By synchronizing to the rotation position of a rotary head 1, a pulse is generated 2, this is waveform-shaped 3, and thereafter, respective types of a timing signal including a head switching pulse to synchronize to the pulse and change over a pair of rotary heads is generated 4. By the counting of a generated 6 clock, a counter 5 detects the length of the half period of the head switching pulse. When an address signal is outputted from the counter 5, a converting circuit 7 sends a corresponding memory value to a memory 8. The counter 5 detects the position of the rotary head in the half period of a switching pulse, respective instantaneous counted values are compared with the output of the memory 8, at the time of coincidence, an FF10 outputs an 'L' signal, a sub-code signal is reproduced during this and supplied to a reading circuit 12.
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