| 摘要 |
<p>A tracking error detection device (1) which, as shown in Fig. 1, converts photocurrent received by a photodetector (2) into voltage signals in current/voltage changers (7a-d), and adds voltage signals in adders (8a, b) to create two signal sequences. The two signal sequences are digitized respectively in ADCs (16a, b) and interpolation-processed in interpolation filters (17a, b), and have zero-cross points detected in zero-cross point detection circuits (18a, b). Phase difference between zero-cross points of the two signal sequences is detected by a phase difference detection circuit (19), and the phase difference is subjected to band-limiting by LPF (11) to thereby obtain a tracking error signal. The above arrangement can provide a small, low-cost tracking error detection device that can accommodate the double-speed of an optical recording/reproducing device and the higher-density of an optical recording medium.</p> |
