| 摘要 |
<p>PURPOSE:To perform excellent tracking even when there is some level difference between reproduced pilot signals by providing a compensating means which compensates frequency characteristics in the band of the pilot signal of a reproducing head and an AGC amplifier which holds the reproduction level of the pilot signal constant. CONSTITUTION:The pilot signal of a reproduced signal is passed through a band- pass filter 16 to obtain only its band, which is inputted to one input terminal of a multiplier 19 through an equalizer 17 and the AGC amplifier 18. Then, signals of difference frequencies F1 and F2 between an oscillation frequency signal and crosstalk components of the reproduced pilot signal are obtained from the multiplier 19. Then, a signal of frequency close to the frequency F1 is extracted by a band-pass filter 20 and a signal of frequency close to the frequency F2 is extracted by a band-pass filter 22; and both are detected by detecting circuit 21 and 23 respectively. Their detection outputs are amplified differentially by a differential amplifier 24, inverted by an inverting amplifier 25, and inputted to an amplifier 27 alternately to control head tracking.</p> |
