PURPOSE: To realize a carrier recovery circuit able to track a high speed phase fluctuation due to rising fading with a small phase slip rate by inputting an extracted carrier component to two kinds of filters whose pass band width differs from each other and using a signal whose phase is an intermediate phase between phases of output signals of the two filters as a reference carrier.
CONSTITUTION: An inputted PSK signal is detected by a detector 1 and a modulation phase is discriminated by an identification device 3 and the PSK signal whose timing is adjusted by a delay circuit 2 is subject to inverse modulation at an inverse modulator 4, from which a non-modulation carrier is obtained. The non-modulation carrier is inputted to filters 7, 8. The pass band width of the filter 7 is selected sufficiently smaller than that for a fading frequency and the pass band width of the filter 8 is selected sufficiently larger than that for a fading frequency. Outputs of both filters are made the same amplitude by limiters 9, 10 respectively and they are synthesized by an adder 11. The phase of an output of the adder is made equal to a mean phase of each filter output. The output is fed back to the detector 1 as a recovery carrier.
SAKAI TSUTOMU
MORIKURA MASAHIRO
KATO SHUZO
