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在普及增量调制器编码调制器的基础上,加上一个自适应反馈环对语音信号和平直频谱信号的模数变换,研制了两种自适应增量调制编码器.采用数字/模斜率检测器和场效应管扩张器构成的自适应电路,集中频谱信号编码器的动态范围,可以扩展到35db以上,而信噪比大于28db,脉冲重复频率只需要32KC.对平直频谱信号,数码率40kb/S时,可以达到同样结果,而且整个频带上信噪比保持不变.所以这种编码器相当于7位码的PCM系统,但首码率都只需要32kb/S或40kb/S.
Based on the universal incremental modulator code modulator, an adaptive feedback loop is proposed for the analog-to-digital conversion of the speech signal and the flat frequency spectrum signal, two kinds of adaptive incremental modulation coders are developed. The digital / analog slope detection And FET dilators constitute the adaptive circuit, focus on the spectral signal encoder dynamic range, can be extended to more than 35db, and signal to noise ratio is greater than 28db, pulse repetition frequency only requires 32KC. Straight spectrum signal, the digital rate 40kb / S, the same result can be achieved, and the signal to noise ratio of the entire frequency band remains unchanged, so this encoder is equivalent to a 7-bit PCM system, but the first code rate only requires 32kb / S or 40kb / S.