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一、为什么要搞数字信号发生在传统的模拟交换网内,信号音(如拨号音、忙音、回铃音)和多频信号均用模拟方法产生.用模拟方法产生的模拟信号音通过模拟的交换网是大家熟悉的.在交换网络数字化后,模拟信号不能直接通过,必须加接模数转换设备,将模拟信号转变成数字信息后才能接入数字交换网.这样经济上既不合算,体积又增大,理想的办法是直接用数字方法产生信号音或多频信号,使之直接注入数字交换网,这样可以节省投资,又可缩小交换机的体积.并从根本上解决了原来用模拟方法产生信号音时存在的振频和振幅稳定较难解决的问题.总之,采用数字方法直接产生数字信号有其明显的优点,也是数字交换必须解决的一个问题.本文
First, why do digital signals occur in the traditional analog switching network, signal tones (such as dial tone, busy tone, ring back tone) and multi-frequency signals are generated using analog methods. Analog analog tone generated by analog Switching network is familiar.After digital exchange in the network, the analog signal can not be directly passed, must be connected to analog-digital conversion equipment, the analog signal into digital information to access the digital switching network.This is not economically cost-effective, the volume But also increase the ideal way is to directly generate digital signals or multi-frequency signal, so that it directly into the digital switching network, it can save investment, but also reduce the size of the switch and fundamentally solve the original analog method When the signal tone is generated, there is a problem that the vibration frequency and the amplitude stability are difficult to be solved.In short, the direct digital signal generation using the digital method has obvious advantages and is also a problem that the digital exchange must solve.