| 摘要 |
<p>PURPOSE:To attain rapid and accurate switching, by discriminating a frequency ratio between a reproduction control signal, and the rotating pulse of a capstan, and switching the rotating speed of a rotary cylinder and a capstan motor based on a discriminated result. CONSTITUTION:A tape speed/field frequency discrimination circuit 40 detects the frequency ratio between an FG pulse from a waveform arranging circuit 13, and a control signal from a waveform arranging circuit 11, at time of reproduction. And based on the above detection, it is decided that a mode is a standard mode of field frequency 600Hz, and tape speed 33.35(-)/s, if the frequency ratio is '24' and the frequency of a reference signal being generated from a reference signal generator 15, the targeted value of a speed detector 21, and the comparison timing of a phase comparator 12, are switched. Furthermore, the targeted value of a speed detector 14 is switched by a tape speed setting signal, and it is controlled so as to set the rotating speed of the rotary cylinder 1 at 20.97Hz, and the tape speed at 33.35(-)/s.</p> |
