CARRIER SYNCHRONISM DETECTION CIRCUIT FOR QPSK DEMODULATOR

摘要

PURPOSE: To enable exact synchronism judgement of a modulating signal at the time of regenerating a carrier by the use of simple circuit configuration. ;CONSTITUTION: A carrier synchronism detection part 10 is provided with a level detection part 1 which level-detects the I patterns of inphase data and quad phase data, which are inputted from a carrier regeneration part 8, a latch part 2 holding/outputting data from the level detection part 1 and a phase shift part 6 inputting a signal synchronized with a clock signal in a clock regeneration part 9 to the latch part 2. Furthermore, an inter-channel synchronism comparison part 3 detecting the simultaneous synchronism of ICH and QCH, an integrator 4 integrating ICH and QCH, which are synchronism-detected in the inter-channel synchronism comparison part 3, and a synchronism judgement part 5 judging synchronism by the integrating result of the integrator 4 are provided.;COPYRIGHT: (C)1996,JPO