| 摘要 |
<p>PURPOSE:To keep a relative speed between a rotary head and a tape constant by detecting the specific signal frequency of a signal reproduced by the rotary head, and controlling the rotating speed of a drum so that the specific signal frequency has an invariably specific value. CONSTITUTION:A signal converted to a TTL level by the 2nd waveform shaping circuit 5b is inputted to an f2 frequency detecting circuit 8 and an f3 frequency detecting circuit 9 to detect an f2 signl and an f3 signal. An f1 signal is recorded next to the f2 signal and the f3 signal without fail, so when either of the f2 or f3 signal is detected, the frequency f1 is already counted and the counted value of an f1 frequency counter 6 is latched in a digital comparator 7 through an OR gate 10 with the output signal of the f2 frequency detecting circuit 8 or f3 frequency detecting circuit 9. Then, the latched counted value is compared with a reference value to output correction data corresponding to the difference, and the rotating speed of the drum is controlled on the basis of the output value to make the relative speed between the rotary head 2 and tape 2 constant.</p> |
