| 摘要 |
PURPOSE:To correct proper amount in response to the property of a correction object even in a transmission line where phase jitter and frequency offset exist in mixture by providing a correction amount switching function with respect to a different phase deviation in kinds at carrier recovery. CONSTITUTION:After a phase modulation signal is shaped by a waveform shaping section 2, the signal is fed to a differentiation pulse generating section 3 and a phase change point is detected by a phase change point detection section 5 and the result is outputted as a gate signal via a gate signal generating section 6. An undesired component is eliminated from both outputs by an AND circuit 4 and fed to a phase comparison section 11 as a phase comparison signal. On the other hand, the clock signal is divided into clock signals 22, 23 whose phase differs by 180 deg. at a biphase clock generating section 8 and the signal 22 is controlled by a phase lead correction signal 20 supplied from a control variable switching section 12 in a clock control section 9 and the signal 23 is controlled by a phase lag correction signal 21. Thus, the phase jitter and frequency offset are discriminated to switch the phase control variable, the phase jitter correction quantity is set to be less and the correction of the frequency offset is set to be large. |
