Improved algorithm for DS-QPSK phase error detection and its digital implementation
DS-QPSK相位误差检测算法改进与数字化实现

According to the correlation orthogonality of Pseudorandom Noise (PN) code used in the direct sequence spread spectrum and QPSK modulation (DS-QPSK) system, a carrier phase error detection algorithm for DS-QPSK signal was proposed. One channel of the DS-QPSK signal could be simplified by the high correlation orthogonality of PN code, and then phase error detection was implemented through the reference of detecting phase error for BPSK signal with arc tangent function. This method was simulated and implemented in computer. Experimental results indicate that the phase error detection algorithm can decrease Signal Noise Ratio (SNR) of the receiver and improve the receive sensitivity of the system.