A wide pull-in range fast acquisition hardware-sharing two-fold carrier recovery loop

This paper proposes a two-fold carrier recovery loop that possesses ±25000-ppm pull-in range and 7-ms acquisition time for 64-QAM blind adaptive system. The carrier recovery system contains a prior wide-band loop to acquire a coarse carrier frequency and a posterior narrow-band loop to achieve -82dBc jitter suppression. It can be applied to a 4.035-MHz low-IF cable modem system with the ±100-kHz frequency offset tolerance requirement. The two-fold carrier recovery loop operates in consecutive three stages, which are Costas carrier phase estimation, DDML carrier phase estimation, and DD-MMSE carrier phase estimation. The proposed architecture is hardware efficient since the three-staged operation shares most of the circuit functions.