Research On Signal Reconstruction Technology Based On Low Complexity Filter Bank

In the process of signal transmission,the signal usually needs to be processed by analog-to-digital conversion or sampling rate conversion,and the receiving end of the signal needs to restore the processed signal to the original signal,which is called signal reconstruction technology.At present,signal reconstruction technology is widely used in communication and radar,speech and image processing,optical communication and other fields.Multi-rate signal processing is an important part of signal reconstruction theory,and the core of which is the filter bank consisting of filters which has the related frequency characteristics.In this paper,two types of signal reconstruction structures and design methods based on low complexity filter banks are proposed.Firstly,the basic theory of the filter bank is introduced.The principle of polyphase filtering is applied to the basic structure of the analysis and synthesis filter bank,and the structure of the analysis and synthesis filter bank based on the polyphase structure is derived.On this basis,a combination of analysis and synthesis filter banks is used to implement signal reconstruction.Through the signal simulation results,we can see the correctness of the deduced structure.However,due to the non-ideal characteristics of the filter,the reconstruction effect is not ideal,which leads to two low-complexity filter bank design methods studied in this paper.Secondly,two types of signal reconstruction structures based on low complexity filter banks are given.One is based on Frequency-Response Masking(FRM).FRM technology is a classic method that can narrow the filter transition band without increasing the computational complexity.FRM technology is applied to the polyphase structured filter bank,the FRM-based signal reconstruction structure can be obtained by performing polyphase decomposition on the masking filter bank in the FRM structure.The computational complexity of the FRM structure is low and it is not limited by high sampling rates and can be widely used in many fields.The second is based on the Fast Filter Bank(FFB).FFB is one of the design methods of multi-channel narrow transition band filter bank with both low complexity and good frequency response.By transforming the fast Fourier transform and the inverse fast Fourier transform filter bank,the basic structures of the FFB-based analysis filter bank(AFFB)and the FFB-based synthesis filter(SFFB)are derived.The parameters of the prototype filter in each channel of AFFB and SFFB are designed,and the sub-filter transfer function and channel transfer function of each channel in AFFB and SFFB are obtained through the binary coding of the channel and the impulse response coefficients of the prototype filters at each level.Then the signal reconstruction structure based on FFB is obtained.Based on the simulation results and the analysis of the complexity and reconstruction performance of each reconstruction structure,it can be seen that the complexity and reconstruction error of the FFB-based signal reconstruction design method are low,and the reconstruction performance is good.Finally,the System Generator software platform is used to implement the analysis filter bank of the reconstruction structure.System Generator software design and module construction are completed,and the correctness of the designed structure was verified by simulation.