Design Of CSD Code FIR Digital Filter Based On Time Division Multiplex

A great progress in the discipline of digital processing is the research on design method of digital filter. FIR digital filter plays a significant part in the processing of digital signal because it can realize linear phase so conveniently that the group delay doesn't vary with frequency.Traditional design methods of FIR digital filter include window function method, frequency sampling method and equal ripple apoproximation method. To design a FIR digital filter with aid of window function method is to use finite length pulse response sequence to approach infinite length pulse response sequence. Its basic design concept is to achieve linear phase and FIR digital filter by first selecting an ideal frequency selective digital filter, and then intercepting its pulse response.Available related references have been studied, the development status and application level of FIR filter has been concluded. The basic architecture and design principle of FIR filter has been carefully analysed, a design method that is CSD code FIR digital filter based on time division multiplex is brought forward. As a example, a 16-rank FIR low passing digital filter is given to discuss the approach. The design was described by VHDL, which was simulated, synthesized and verified under Quartus II. And The results show that the circuit works reliably and perfectly.Canonic Signed Digital (CSD) is based on the ternary number (-1,0,1),which has the advantage of reducing the non-zero bits of the number. In the paper, an algorithm for conversion of a 2's complement to canonic signed digit number system was introduced. The experimental results show that this method requires fewer hardware resources.We also describe how to combine the MathWowks Co.'s MATLAB software with Quartus II so as to strengthen the Quartus II's simulation function.