Coherent Demodulation Technologies of Software Radio QPSK Based on DSP

The software radio station based on DSP requires a quick and accurate realization of functions including demodulation and decoding etc. So it has a high demand on the efficiency. The software radio station has its own agility so that special treatment must be taken to meet the needs. This article realizes a real-time communication platform using SDR technology on the TMS320C6201 DSP. The platform includes real-time encoding and decoding, full-automatic mode recognition, modulation and demodulation, etc. The improvement of the key technologies including software phase lock, judging, software bit-synchronization and the system optimization is emphasised. The result is as expected and the improvement of the algorithms in the article is effective.