| 摘要 |
PURPOSE:To eliminate the need for single balance conversion and to provide the optical reception circuit with high accuracy by employing a master slave FF type discriminator for a discriminator and using a noninverting signal and its inverting signal so as to implement offset compensation. CONSTITUTION:An optical signal from a light receiving circuit 2a is converted into an electric signal DIN, it is amplified by an amplifier 3 and a signal DOUT is inputted to a master slave FF type discriminator (MSFF) 4. The discriminator 4 compares the signal with a reference voltage DREF from a reference signal generating circuit 6 and outputs logical values QT, QC to a signal processing section 5. On the other hand, a noninverting output DT and an inverting output DC of the master section in the discriminator 4 are respectively inputted to peak hold circuits 8-1, 8-2, in which an amplitude maximum value of the outputs DT, DC is held respectively in them. Signals PT, PC to be held are inputted to an error amplifier 8-3 and an offset compensation signal DOFF is generated so as to make a difference between the signals PT and PC zero thereby compensating the offset automatically. |
