| 摘要 |
PURPOSE:To prevent the divergence of an automatic equalizer against momentary interruption or rapid level change by releasing the stop of equalization against the level change of an adaptive automatic equalizer at a prescribed time after the level restoration. CONSTITUTION:If the synchronizing step-out between the timing phase of a timing recovery circuit 4 and the carrier phase and frequency of a carrier recovery circuit 3 takes place depending on the state of a signal inputted to a demodulation circuit during level change and on the length of an error after the restoration of signal level change, a pulse expanding circuit 10 sets the time (t) of expansion of a signal 102 larger than the synchronization time to the maximum deviation of the carrier phase and timing phase so as to stop the tap correction of the equalizer 2 when the synchronizing step-out between the carrier phase and timing phase during a faulty modulation wave level and after its restoration exists thereby restarting the tap correction win the stage of re-establishment of the synchronization after the restoration and suppressing smaller the equalizing error 104 of an identification circuit 7 after the restart of tap correction. |
