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在载波通信系统中,由于高频的线路衰耗较大,当各路的发送电平一样(平发送)时,传输频率较高的通路其信号对杂音的防卫度较低。为了提高线路传输频率较高通路的防卫度,压低线路传输频率较低通路的防卫度,在对称电缆和同轴电缆载波系统中,往往采用发送电平预先倾斜(即斜发送)的办法。电平预斜会使放大器的负载起变化,但应使放大器的负载在斜发送时与平发送时的一致,以免因电平预斜而使放大器负载增加,导致易过负荷。也即是说,预斜程度应满足发送放大器输出端的总平均功率在有预斜和无预斜时两种情况接近相等。同时电平预斜会使发送放大器的非直线性产物分布有所变化,计算非线性产物时所
In a carrier communication system, the channel with high transmission frequency has a low degree of protection against noise when the transmission level of each channel is the same (flat transmission) since the attenuation of the high-frequency line is large. In order to improve the defense of the channel with higher transmission frequency and to suppress the defense of the channel with lower transmission frequency, the transmission level is pre-tilted (that is, oblique transmission) in the symmetrical cable and the coaxial cable carrier system. Pre-ramp level will change the load on the amplifier, but should make the amplifier load in the oblique send and send the same level, so as not to pre-ramp the level of the amplifier load increases, leading to easy overload. That is to say, the pre-skewness should meet the total average power at the output of the transmit amplifier in both cases with and without pre-skew. At the same time the level of pre-tilt will send the amplifier non-linear product distribution has changed to calculate the time of non-linear products