BASE BAND DIFFERENCIAL DETECTOR OF PI/4 QUADRATURE PHASE MODURATION SIGNAL

摘要

PURPOSE: A differential detector for detecting the base band of a pi/4 differential quadrature phase shift keying signal is provided which reduces bit error rate caused by transmission channel characteristic using the characteristic of pi/4 differential quadrature phase shift keying and simplifies a hardware configuration. CONSTITUTION: An absolute phase detector(401) receives sample data items(Wk,Zk) and sets the sample data values to one of four values each symbol can have according to a control signal indicating an odd symbol or even symbol. A differential phase demodulator(307) calculates a sine value and cosine value for differential phase using the data items of the absolute phase detector at the current point of time and the point of time before the current point of time. A data determination unit judges the signs of the data items of the differential phase demodulator to convert the data items into symbol data items(Xk,Yk) corresponding to the signs.