数字带通滤波器的设计过程。共3个源程序。其中，dos.cpp为带通FIR的源程序，其中的滤波器阶数n，滤波器的低频fln，滤波器的高频fhn，窗函数w，可以按照自己的要求改变。这里采用的是汉宁窗。主函数main.cpp实现输入与fir的h(n)的卷积，输出结果Y(n)，并将其存储在y.txt中。最后，graphics.cpp从y.txt读取数据，再由语句画出波形，可以清楚地看出计算结果是否正确，并进行比较。-digital band-pass filter design process. A total of three sources. Among them, dos.cpp FIR bandpass to the source, the filter order n, the low-frequency filter FLN, the high-frequency filter fhn, window function w, in accordance with the requirements change. Here is the Hanning window. The main function main.cpp achieve the input and fir h (n) convolution, the output Y (n), and store them in y.txt China. Finally, graphics.cpp y.txt read data from and then draw waveform statement, we can clearly see whether calculations are correct, and comparisons.