％ y=filter(sig,fmin,fmax)

％ 对信号进行理想滤波，可完成低通，带通

％ sig为被滤波信号

％ fmin为下限频率，当fmin为0时为低通滤波器，当fmin>0时，为带通滤波器

％ fmax为上限频率，fmax>fmin

％ fs为信号的采样频率

％ y为经过滤波后的信号

-％ Y = filter (sig, fmin, fmax)％ of the ideal signal filtering, to be completed by low-pass, band-pass filter％ sig for signal％ fmin is the minimum frequency, when fmin for 0:00 for the low-pass filter, when fmin >　0, for the bandpass filter％ fmax is the upper limit frequency, fmax>　fmin％ fs for signal sampling frequency％ y for the filtered signal