Broadband Dynamic Digital Receiver Communications Signal Modulation Recognition

Communication signals travel in space with different modulation formats. In many applications, it is required to monitor the activities of these signals, identify their characteristics, even to intercept the signal information content. For instance, we may wish to monitor their transmissions in order to implement signal confirmation, interference identification and spectrum management. In military applications, we need monitor electromagnetic spectra activities, implement threat detection and warning, process communications Counter-Measures. This thesis designs a wide band dynamic digital receiver. It accomplishes a signal analysis system based on the theory of softwareradio,which can blindly receive and demodulate several signals as well as abstract useful information. This thesis emphasizes the communication signal-processing module, especially the key part—the recognition part of signal modulation, which is the foundation of the signal filtration and demodulation. Communication signal recognition is one of the basic functions, being heat researched in the signal-processing field in recent years. We indicate a signal modulation recognition method based on pattern recognition theory. It can effectively recognise many modulation types, including AM, ASK, FM, FSK, PSK and so on, on the condition SNR>5db. After enumerate all the processing general situations, we elaborate on the signal characteristic abstraction and recognition. In engineering practice, the algorithms above are simulated with MATLAB. Both theoretical analysis and simulation justify the effectiveness of the algorithms.