正弦振荡器 meaning in Chinese

pure oscillator

Section ii describes the design approach and implementation of speech module on mcf5249 coldfire core . the speech codec optimizes g . 729a codes and added voice activity detection of g . 729b to save bandwidth ; the implementation of acoustic echo cancellation uses nlms algorithm and it can reduce echo though designing adaptive fir filter and speech detector ; the dtmf and cpt generate signal using two second order digital sinusoidal oscillators and detect signal by picking up the frequency information . but only get the frequency information is not enough in cpt detector , this thesis introduces a method
其中对语音编解码器的设计采用优化g . 729a代码达到设计要求,并在此基础上加入g . 729b的静音检测模块,以进一步降低网络传输带宽;对回声消除器的设计采用nlms算法,通过设计自适应fir滤波器和语音检测器达到回声消除目的;对双音多频设计,信号发生端采用构造静态参数表并通过二阶正弦振荡器产生信号,信号检测端提取频率信息以检测信号;对呼叫进程音设计,除了类似双音多频的信号发生及频率检测设计外,还需要检测信号持续时间,作者设计了一种基于匹配状态表的方法以检测信号持续时间。