Abstract:Using band-pass filter can make the signal bandwidth less than the channel bandwidth, so voice signal will more matching channel. Through TMS320VC5509 McBSP configuration the chip of the voice codec TLV320AIC23, then put the voice data passing through a FIR band-pass filter, filter out noise outside the passband, so that we can get better signal transmission. The experimental results show that the sound quality improved significantly after the band-pass filter.