A carrier recovery algorithm for high order QAM

In this paper, a polarity decision and phase detection algorithm is presented, which is useful for carrier acquisition in high order QAM, such as 64QAM, 128QAM and 256QAM, in order to acquire the frequency offset in DVB-C system. The proposed carrier recovery algorithm can acquire frequency offset of high order QAM signals up to 200 kHz, The conventional DD algorithm can acquire small frequency offset. When receiving a baseband signal with large frequency offset,big noise and part multipath, a large frequency offset can be acquired by using polarity decision algorithm firstly. Finally when stabilized, the remaing small frequency offset can be acquiredwith full constellation decision.