Digital Demodulation Of Communication Signals And Modulation Recognition

Modulation and demodulation recognition technology is widely used in military communication and civil communications. Communication signals'modulation recognition and parameters extraction is very important for communication interference, reconnaissance, audio-visual of the enemy signal These techniques of communication signals can also be used in signal validation, interference identification and extraction signal frequency, etc.This paper introduces several common modulation and demodulation of digital communications technology, on this basis, design and implementation of FPGA-based 2PSK, ASK, QPSK, 2FSK, 8FSK, 2DPSK, QDPSK 7 kinds of digital communication signals'demodulator, and the 7 different demodulator used in the same design module, to achieve its universal demodulator effect, and analyzing and comparing actual results with the theoretical results. Then introduces the digital communication signal modulation feature extraction and modulation recognition technology base on decision tree classifier, DSP-based modulation recognition technology, programming and implementation, given to the classification and recognition results Such as 2ASK, 2FSK, 8FSK, 2PSK/2DPSK, QPSK/QDPSK.Finally, discussing interference technology about several digital communication signal, statistics of the interference effect. After integrating the above three techniques, used in communications and communications countermeasure experimental instrument, and conducted a system debugging and testing, practical results demonstrate the rationality of its design.