本来想做一个BPSK的调制和解调的混合编程实验，由于混合编程的库里面没有butter、cheby1等滤波器函数，用C编又不会，所以只好请教高手了。呵呵~-Originally wanted to do a BPSK modulation and demodulation of the mixed-programming experiment, as a result of mixed programming library There are no butter, cheby1 function

利用IIR滤波器对信号滤波,保留200Hz以下频率，使用CHEBY1滤波器-filtering to signal using IIR