％ 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 com

PN码在BPSK调制下基带和频带的同步,包括带通滤波，低通滤波，pn码产生(PN code in BPSK modulation baseband and frequency band synchronization, including band-pass filtering, low-pass filtering, PN code generation)