PURPOSE: To reproduce a signal correctly and uniformly over the whole of an information recording medium, by correcting the frequency characteristics of the playback signal according to its playback position.
CONSTITUTION: When the reproduction of a disk 1 by a reproducing stylus 2 starts at the external circumference side, the intermittence of pits is picked up in the form of variation in electrostatic capacity and a signal which corresponds to the variation is made into a sine wave signal, which is supplied through an AGC circuit 3 and a cosine equalizer 4 to a limiter 5, generating a rectangular wave signal which corresponds to the sine wave signal. The rectangular wave signal is supplied to and demodulated by a demodulator 6, and consequently a digital signal sequence appears at an output terminal 7 and is converted into a PCM signal, which is reconverted into an original audio signal by a D/A converter. While the lower-side wave band is extracted through a low-pass filter 8, the upper-side wave band is extracted through a high-pass filter 9, and they are rectified by rectifying circuits 10 and 11 and then integrated by integrators 12 and 13 to generate DC voltages which correspond to those side bands.
| WO/2003/019557 | RECORDING APPARATUS FOR RECORDING DATA ON OPTICALLY READABLE DISCS |
| WO/2005/045832 | A LOW POWER DATA STORAGE SYSTEM AND A METHOD THEREOF |
| JPH04177675 | OPTICAL DISK FILE SUBSYSTEM |
NISHIKAWA KAZUNORI
IWASAKI YOSHIKI
FURUMURA MAKOTO
| JPS5312228A | 1978-02-03 |