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本文提出一种新型的用于移动通信的话音置乱器。其原理是,按照置乱码有选择地倒置话音样点的极性,由低通滤波器平滑,再馈送到无线电台发信机。为利用这个原理,本文对必需采用的技术,诸如滤波、同步以及置乱码设计等做了描述。置乱后话音的白噪声频谱和大量的密钥编码,使这种置乱器能提供高保密度的通信。本文提出的置乱器,特别适合配用按键讲话式的移动无线通信机。本文还展示了通过置乱而产生的话音频谱的变化,并测量了有无衰落的条件下可懂度随信噪比(S/N)变化的情形。这些结果表明,这种置乱方法特别适用于那种要求按键讲话电台快速同步,以及具有抗扰与抗衰落能力的移动式通信。
This paper presents a new type of voice shuffler for mobile communications. The principle is that the polarity of a speech sample is selectively inverted according to the scrambling code, smoothed by a low-pass filter, and fed back to the transmitter of the radio station. To take advantage of this principle, this article describes the necessary techniques such as filtering, synchronization, and scrambling code design. Scrambled speech white noise spectrum and a large number of key code, so that this scrambler can provide high-security communications. The disarming device proposed in this paper is especially suitable for the mobile radio equipped with push-to-talk. The article also shows the changes in the frequency spectrum of the speech caused by scrambling and measures how the intelligibility changes with the signal-to-noise ratio (S / N) in the presence or absence of fading. These results show that this method of scrambling is particularly well suited for mobile communications that require push-to-talk radio stations to synchronize quickly, as well as immunity and fading immunity.