| 摘要 |
PURPOSE:To perform tracking controlling operation stably by recording the 3rd reference signal in a switching position every rotation between the 1st and the 2nd reference signals for tracking control and selecting the frequency of the 1st-3rd reference signals lower than the recording band of a main information signal. CONSTITUTION:The figure shows an example of a block diagram of a rotary recording medium reproducing device. A reproducing signal read out from a disk 30 by a scanning stylus as a fine change of electrostatic capacity is supplied to a preamplifier 41 having a resonance circuit changing resonance frequency in accordance with the change of the electrostatic capacity, turned to a signal with a required level and then divided into two parts. One is outputted from an output terminal 42 to a demodulator (unshown) to reproduce a main information signal and the other is supplied to a low pass filter 43, which separates and filters a low frequency component lower than the main information signal recording band and supplies the filtered signal to an AGC circuit 44. The low pass filter 43 is connected to separate reference signals fP1-fP3 from the main information signal so that only required frequency components are filtered from these reference signals. |
