| 摘要 |
<p>PURPOSE:To attain phase servo with excellent response by obtaining an FG (frequency generator) detection signal at a period being divisions of one rotation of drum divided equally. CONSTITUTION:A time difference detection circuit 21 detects and stores a difference between an FG detecting signal and a PG (phase generator) detection signal. A correction circuit 22 retards the FG detecting signal by an output of the circuit 21 to obtain the FG detecting signal (FG' signal) at a position dividing one revolution of the drum equally. The FG' signal counts up a counter 23. An FG reference signal generating circuit 24, based on a PG reference signal, generates a signal having a frequency being e.g., 24 times (800Hz) the frequency of the PG reference signal as the FG reference signal. A counter 25 is counted up by the FG reference signal. A phase comparator 26 compares the phase of the FG' signal with that of the FG reference signal and phase-locks a drum motor 28 in response to the phase error. Through the control above, an error signal is sampled at 800Hz to quicken the response speed.</p> |
