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本文是一种语音频带声换能器(受话器)的初步实验报告,该受话器能接受数字(PCM)信号,并能将所接收的码位直接转换成模拟声输出。本文介绍了4、5和6位数字受话器的初步设计和一种功能相当于信号解码用的解样滤波器的声学系统的初步设计。文中报告了该数字受话器的频响、振幅线性和信号一量化噪声比的测量结果。结果表明,这些参量都在预期的设计范围内。虽然初样是比较原始的,但该种换能器却能以可以接受的保真度完成直接的数字转换,这就为数字语音系统中减少每条线路设备的复杂性提供了一条途径。
This article is a preliminary experimental report on a speech-band sound transducer (receiver) that accepts a digital (PCM) signal and converts the received code bits directly into an analog sound output. This article presents the preliminary design of the 4, 5 and 6 digital receivers and a preliminary design of an acoustic system that functions as a decimation filter for signal decoding. In this paper, the measurement results of frequency response, amplitude linearity and signal-to-noise-ratio of the digital receiver are reported. The results show that these parameters are within the expected design range. Although the prototype is relatively primitive, the transducer achieves direct digital conversion with acceptable fidelity, providing a way for digital voice systems to reduce the complexity of each line device.