| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical recording and reproducing circuit which can cope with optical disks having different formats, reduces the influence of noise and has the reduced number of parts and has the circuit constitution simplified. SOLUTION: When a signal recorded on an optical disk of a format corresponding to one laser diode is reproduced, a first signal reproducing system (photo diodes 21A to 21D, I-V converters 31A to 31D, operational amplifiers 61A to 61D, address 41A and 41B, and an operational amplifier 64) and a common signal processing system (photo diodes 23A to 23D and I-V converters 33A to 33D) are used to reproduce the signal. When a signal recorded on an optical disk of a format corresponding to the other laser diode is reproduced, a second signal reproducing system (photo diodes 22A to 22D, I-V converters 32A to 32D, operational amplifiers 62A to 62D, adders 42A and 42B, and an operational amplifier 65) and the common signal processing system are used to reproduce the signal. |
