Research Of Non-uniform Bandwidth Channelizer Based On Perfect Reconstruction

With the development of satellite communication, the effective load of satellite communication is higher, which is expected to complete the flexible conversion of the signal with any frequency band and arbitrary bandwidth. The channelizer based on filter bank structure meets the requirement without losing the speed of communication. Perfect reconstruction based non-uniform bandwidth digital channelizer, in the case of almost no signal loss, to achieve uniform bandwidth and non-uniform bandwidth of signal exchange, has important application value.In this thesis, we study the design and implementation of a non-uniform bandwidth channelizer based on the perfect reconstruction, the main work is as follows:A perfect reconstruction based prototype filter of two channel s filter banks is designed. A dual optimization for the prototype filter is carried out to obtain a good stop band attenuation and cutoff frequency. Based on the basic characteristics of the lattice structure, the first level optimization use the method of step by step and channel by channel. The second level optimization use the search method. After the optimization, the attenuation of the prototype filter can reach-93.38 dB.The perfect reconstruction based prototype filter of multi-channel filter banks is designed by interpolating non-zero to the perfect reconstruction based prototype filter of two channels filter banks. In order to interpolate the zero will produce specular component, interpolating a non-zero value is a kind of improvement on the basis of that, reduction of distortion caused by the specular component. The stop attenuation of the 64 channels and 768 long filter banks obtained by this method can reach-99.18 dB.By using the DFT modulation filter banks and the multi-phase component technique, a channelizer is constructed to realize the signal transmission of the non-uniform bandwidth. In the transmission of the channel, by setting protection interval, the signal that occupies several basic sub channels can be perfect reconstructed. Analysis and simulation show that using the filter that the length is 1024, by BPSK modulation, the bit error rate of the signal is at 10-5 when the E_b/N₀ is 10 dB.