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选址通信系统中一次调制的作用,是把话音由信号调制成二进制码。对一次调制的基本要求是码速要低、发码率要低以及最小码间的间隔要大等,以减少伪地址数,从而达到增加总地址数和同时通话台数的目的。这里介绍一种在二值增量调制的基础上加以改进的自适应增量调制器(DATEC)及改进型自适应增量调制器(改进DATEC)。这种调制器能大大减少发码率,且电路本身具有自然的话音开关性能。
The role of a modulation in the site communication system is to modulate the voice signal into a binary code. The basic requirements of a modulation is to lower the code rate, the code rate is low and the minimum interval between the code to be larger, in order to reduce the number of pseudo-address, so as to increase the total number of addresses and the number of simultaneous calls purpose. Here we introduce an adaptive delta modulator (DATEC) and an improved adaptive delta modulator (improved DATEC) based on binary delta modulation. This modulator can greatly reduce the code rate, and the circuit itself has a natural voice switching performance.