An algorithm to perform frame synchronization and estimation of phase ambiguity of MPSK modulated symbols is presented,with the method of setting two thresholds and a simplified correlation which can reduce half the computing complexity,and performance of the synchronizer are analyzed.

Then,a new multistage blind subtractive clustering algorithm is used to identify the two different classes of modulation formats(MPSK/MQAM(M-ary phase shift keying/M-ary quadrature amplitude modulation)) and to determine the number of the signal constellation points as the result of the modulation classification.