CARRIER RECOVERY CIRCUIT

摘要

PURPOSE:To allow the circuit to trace a high speed phase fluctuation such as slice fading and to reduce a phase slip rate by using two systems of carrier recovery means having a narrow band filter and a broad band filter. CONSTITUTION:A received modulation signal is inputted to a synchronization detector 18 via a delay circuit (D) 17 and detected by using a recovered carrier outputted from a phase adder 13. In this case, a pass band width of a filter 441 of a 1st carrier recovery means 11 is made sufficiently narrower than the fading frequency and a pass band width of a filter 442 of a second carrier recovery means 12 is made sufficiently broader than the fading frequency to extract a mean value component of the carrier phase at an output of the 1st limiter 451 and to extract a fluctuation component of the carrier phase at an output of the 2nd limiter 452. Then a phase adder 13 adds the fluctuation component obtained through the processing of the recovered carrier in the 2nd carrier recovery means 12 to the phase average component of the recovered carrier obtained by the 1st carrier recovery means 11.