Evaluation And Software Realization Of Interception Algorithm On Communication Signal

Information technique plays more and more important role in advanced military fields. Electronic warfare, whose intention is to control the electromagnetism, is the most important core subsystem of information warfare. And Communications Counter-Measures is a main part of electronic warfare. It becomes a key factor determining the war victory or defeat. With the swift and violent development of DSP(Digital Signal Processor's technology, furthermore the performances of general computer are greatly improved, when analog signal is turned to digital signal by ADC(Analog Digital Change), The processing of digital signal can be well finished by the software running in a general computer .It makes the system's real-time processing can be improved obviously.After we intercepted the mixed signals of transceivers more than one, we estimate the number of signals and the directions of arrival (DOA), form the beams of every transceiver, focus the partition points between the noises, the transients generated when a transceiver turned on and the communication signals. For the communication signals, we detect if there exist Frequency-Hopped (FH) signals and estimate the parameters of FH signals ; if there exist normal communication signals.and identify the modulation types . The modulation recognition system which was built in this thesis can auto identify 7 kinds of analog modulations such as AM, DSB, USB, LSB, CW, FM, AM-FM and 7 kinds of digital modulations such as 2ASK, 4ASK, 2FSK, 4FSK, 2PSK, 4PSK, 16QAM. It can also eatimate the parameters of FH signal .The system are realized by the way of mix programming between VC&matlab.The structure of this thesis is as follows:Chapter 1 introduces this research project's importance in military area and composeing the whole structure of the arithmetics .Chapter 2 reviews every child module according to the flow of the mixed signal preprocessing, that is intercepted ,and the selection about arithmetic of each module ,all of them are implemented in matlab.Chapter 3 simulates extracting the parameters for recognize the types of modulation,estimates their performance ;to the dissatisfactory parameter, we proposed the method to improve this performance..Still, some of the algorithms' efficiency are validated by the collected real signals.Chapter 4 introduces the realization of this software's figure interface, as compared the ways of mix programming between VC&matlab ,we determined to use the client/server method that is suitable to this system. It is important to disengage this system from matlab when the tasks of the arithmetics and others are all finally finished ,and this method is also introduced .