Artificial Neural Network Used In The Study Of The Communication Signal Digital Modulation Of The Automatic Identification And Implementation

This paper makes research on the approach of the artificial neural network (ANN) for automatic digital modulation recognition process of communication signals, and constructs an automatic digital modulation recognition system with ANN. Synthesizing the instantaneous amplitude, frequency and phase of all kinds of basic digital modulated signals , this paper proposes five characters which form a complete and essential character vector space in which 2ASK, 4ASK, 2FSK, 4FSK, BPSK, QPSK and QAM can be distinguished, and presents two neural network structures, BP network and SGFM network , and unites them to construct an ANN modulation classifier.Computer simulations of different types of digitally modulated signals have been carried out to measure the performance of the system. The overall success rate is not less than 94% at the signal- to- noise ratio (SNR) of no less than 10 dB. Furthermore, this system is applied to on-line automatic modulation recognition of real satellite signals. Recognizing a signal takes no more than ten seconds. And the system can classify signals at different frequencies by training their stylebooks, which behaves intelligently.