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明线载波电路在我国长途通信中,占有很大的比重.当前明线载波电路质量上存在的主要问题是电路串杂音大,造成电路串杂音原因很多,问题也比较复杂,但是我们只要抓住线路上、机器设备和维护中的几个主要问题,从它入手,则电路质量是可以提高的.大家知道,电路的串杂音包括串音和杂音,串音又包括路际串音和制际串音.杂音对传输信号起掩盖作用,降低了语言清晰度.关于杂音对传输信号的影响,不仅要考虑杂音本身的大小,更重要的是考虑传输信号对杂音干扰的防卫能力,如果传输信号和杂音电平差值(指P信一P杂)越大,则说明传输信号对杂音防卫能力越强.我们把传输信号电平与杂音电平的差值叫做杂音防卫度.显然,杂音防卫度越高,抗干扰能力越强,杂音防卫度越低,传输信号受干扰越严重.
Clear line carrier circuit occupies a large proportion in China’s long-distance communications.Current quality of the existing line carrier circuit is the main problem is the circuit noise, resulting in a lot of circuit noise, the problem is more complicated, but as long as we grasp the line , Machinery and equipment and maintenance of several major issues, from it to start, then the circuit quality can be improved.As we all know, circuit noise, including crosstalk and crosstalk, crosstalk, including inter-city and inter-system crosstalk Mash on the transmission signal from the cover effect, reducing language clarity on the noise on the transmission signal, not only to consider the size of the murmur itself, more importantly, consider the transmission of noise on the signal interference defense capabilities, if the transmission of signals and noise Level difference (P letter a P miscellaneous) is larger, then the transmission signal on the noise defense ability is stronger.We transfer the signal level and noise level difference is called the noise defense.Obviously, the noise protection degree High, stronger anti-interference ability, the lower the noise defense, the more serious the transmission signal interference.