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本文在增量调制器基础上提出一种新的语音信号编码调制系统.这个系统的基本概念是将语音信号分解为频率和包给分量.将这两个信息分量分别用编码器进行编码,在将译码得出两个分量之后再组合成原来的语音信号.利用低取样频率的语音编码信号需要大的压扩率以抑制量化失真.而取样频率(数码率)很低时,语音信号两个零交替点之间的取样次数是极少的,在采用瞬时压扩则可以作到大的压扩率,但不能用数控编码.新的系统由于对语音信号用了一个独立的包络检测器克服了这种限制.包络信号以一个独立的取样频率编码并传送到接收端.在发送端,用一个辅助接收机将这个信号译出,并用以控制语音频率信号编码器的量化阶距,从而得到大的压扩率.接收端用译出的包络信号控制频率信号译码器的量化阶距以获得正确的扩张.两个编码器的数字信号利用时分复用的方法进行传输.这个系统可以用7200b/s的数码率得到可懂的语言传输,频率信号传输的低频带宽为2700C,包络信号带宽为50C.编码系统的数码率分别为6800b/s和400b/s.
In this paper, a new speech signal coding and modulation system is proposed based on incremental modulator.The basic concept of this system is to decompose the speech signal into frequency and packet to component.These two information components are encoded by encoder, Will be decoded into two components and then combined into the original voice signal using low sampling frequency of the voice coding signal compression ratio requires a large suppression of quantization distortion while the sampling frequency (digital rate) is low, the voice signal two The number of sampling points between zero-alternation points is very small, and instant compression can be used to achieve a large compression rate, but can not be encoded by the CNC.The new system due to the voice signal using a separate envelope detection This limitation is overcome by the fact that the envelope signal is encoded at an independent sampling frequency and transmitted to the receiving end, and at the transmitting end this signal is translated by an auxiliary receiver and used to control the quantization step of the speech frequency signal encoder , Resulting in a large compression ratio.The receiver uses the translated envelope signal to control the quantization step of the frequency signal decoder to obtain the correct expansion.The digital signals of the two encoders are time division multiplexed Method.The transmission of this system can be understood with 7200b / s digital rate.The low frequency bandwidth of frequency signal transmission is 2700C, the envelope signal bandwidth is 50C.The coding system’s digital rate is 6800b / s and 400b / s.