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在信息社会,特别是在军事通信中,通信保密显得愈来愈重要。电话是通信的主要方式之一。话音信号的加密方法可分为数字和模拟两种,即数字加密和模拟置乱。近年来虽然数字通信及数字话音加密技术有很大的发展,但在相当长的时期内仍要使用模拟窄带信道传输话音信号。数字加密虽然加密效果较好,但大多数数字编码话音信号的带宽都远大于原始模拟话音信号的带宽,难于在模拟窄带信道上传输,参数编码(声码器)的数字话音信号虽能
In the information society, especially in military communications, confidentiality of communications has become increasingly important. Telephone is one of the main ways of communication. Voice signal encryption methods can be divided into two kinds of digital and analog, that is, digital encryption and simulation scrambling. Although digital communications and digital voice encryption technologies have greatly developed in recent years, analog narrow-band channels have still to be used to transmit voice signals for a long period of time. Although digital encryption has good encryption effect, the bandwidth of most digitally encoded voice signals is much larger than that of the original analog voice signal, so it is difficult to transmit on the analog narrowband channel. Although the digital voice signal of the parameter encoding (vocoder)