摘要
在PSTN中,我国采用具有A律压扩特性的脉冲编码调制(PCM)将模拟信号转换为数字信号,但A律压扩特性会损害叠加在大信号上的小信号的性能。通过MATLAB仿真发现:一段正常语音信号,大约有60%的部分可以用于叠加小信号,而几乎不会对小信号造成影响。
The Pulse Code Modulation using A-law companders -- which could damage the small signal -- is adopted to convert the analog signal to the digital signal in China＇s PSTN. Simulation with MATLAB shows that up to 60% of a normal signal could be added to a small signal, and this could bring about little influence to the small signal.
出处
《信息安全与通信保密》
2009年第8期67-69,共3页
Information Security and Communications Privacy
