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随着数字技术的发展,在传输电话信息中采用了32路脉冲编码调制传输系统,该系统传输速率为2048kb/s,并以非线性对数特性A=87.(?)的13折线编码。这些基本原理得到了广泛应用,国际电报电话咨询委员会提出了许多建议,确定了电话通路特性,系列结构及脉冲编码设备的有关参数。近几年来,国内外开始生产符合国际电报电话咨询委员会建议的速率为2048kb/s的30路脉冲编码调制设备,以及更高次群的传输系统,如120路脉冲编码调制设
With the development of digital technology, a 32-channel pulse code modulation transmission system is adopted in the transmission of telephone information, and the transmission rate of the system is 2048 kb / s, and is encoded by a 13-fold line with a non-linear logarithmic characteristic A = 87. These basic principles are widely used, and CCITT made a number of suggestions to determine the characteristics of the telephone path, the series of structures and the parameters of the pulse coding equipment. In recent years, domestic and foreign manufacturers have started to produce 30-pulse modulation and coding systems at a rate of 2048kb / s in line with the recommendations of the International Telegraph and Telephone Consultative Committee, as well as higher-order transmission systems such as a 120-pulse modulation and coding system