设pn序列长度为Lc,为输入信号的Lc倍，输入带宽为f,则经过扩频后，信道中传输信号的带宽为Lc*f,.躁声也衰减为原来的1/Lc。在解调端用相同的pn序列进行解调。这样的好处是频带扩宽了，有利于对传送信号的保密，只有知道调制端的pn序列，才能正确地解调出信号；另外，由于躁声的衰减，在很大程度上降低了误码率-Based pn sequence length Lc, for the input signal Lc times, input bandwidth for f, then after a spread-spectrum, the channel bandwidth for the transmission signal Lc* f,. Attenuation would have been impatient for the original 1/Lc. Demodulation client in the same pn sequence demodulator. This advantage is widening the band, and is conducive to the transmission of signals remain confidential and will only know that side of pn sequence modulation in order to correctly signal demodulation　In addition, since the sound attenuation impatient to a large extent reduce the bit error rate