本文档里含有诸多c++文件，其功能实现有FIR滤波，IIR滤波，，还有正弦曲线，还实现了128点FFT，DFT-This document contains a lot of c++ file, its function to achieve a FIR filter, IIR filtering, as well as the sine curve, but also to achieve a 128-point FFT, DFT

这是一个外文文档,在fft的设计方面有较大的改进,可以当作大家的参考-This is a file writed by english,which has been optimized in fft.It is a good choice for the ones who are working on dsp and fpga.

FFT-based FIR Filter is a unit to perform the finite impulse responce filter based on the Fast Fourier Transform (FFT). It performs the convolution of the unlimited signal sequence with the synthesized impulse responce of the length of Ni=N/2 samples