Radio And Monitor The Design And Realization

Radio spectrum is one of the basic material conditions of radio communication, and it is limited natural resources. This thesis develops a demanding radio station monitor of the National Radio Management Committee. The radio station monitor forms from two parts: the RF(Radio Frequency)front-end and the digital IF(Intermediate Frequency) receiver. The RF front-end converts the monitor spectrum signal into the bandwidth signal of which the center frequency is 455 kHz. According to the demonding request, the thesis contains the design of the digital receiver, the hardware block diagrams and some part of the hardware circuit. It studies on the software defined radio technology and simulates the whole processing which is from the digital down converter to the FFT translation. This thesis adopts software radio technique and controls the flow of work by means of designing programs with the C language. The whole working process is carried out in the DSP hardware platform.And the results are turned out to be correct.In addition to monitoring the radio spectrum, the radio station monitor should also have the signal recognition function. The thesis compares different forms of modulation signal recognition methods, and studys the Nandi methods for a deeper research. The methods of the thesis is on the basis of Nandi methods, and it uses a raised cosine filter to improve the simulate condition. Based on the MATLAB simulation graphs, we can conclude that aiming at the signals including: 2ASK,2PSK,2FSK,4ASK,4PSK and 4FSK, the improved method of the thesis is better than the Nandi method at the success ratio and anti-noise performance. And it is more suitable for the practice project need.