基于误码率的通信系统电磁干扰效应研究

为系统客观地评价某通信系统的抗电磁干扰能力，提出一种以误码率为评价指标的电磁干扰效应实验方法，确定了不同干扰信号对该通信系统的作用规律，分析了干扰机理，结果表明：同频干扰时，在产生误码功率的前2 dBm，误码率逐渐增大，而后1 dBm范围内，误码率迅速增加到0.47，干扰功率与发射功率呈线性变化；误码率达到10^-2数量级，话筒发出吱吱声，达到0.47时显示屏出现死机现象；偏离发射频率2 MHz范围内的信号易产生干扰；带外强干扰信号会使通信系统减敏，干扰功率与信号频偏呈正比；互调干扰的两路信号同步变化时，其功率与发射功率呈线性关系，反之功率与信号频率之间的关系相同；扩频或RS编码可提高通信系统对同频小信号的抑制效果，而对邻频干扰，扩频反而使系统更易受到干扰，且产生干扰的功率区间变宽。

Electromagnetic Interference Effect Research of Communication System Based on SER

In order to evaluate the anti electromagnetic interference capacity of a communication system objectively, an electromagnetic interference experimental method based on symbol error rate (SER) is brought, and then the coupling law of different interference signals is confirmed; the interference mechanism is also analyzed. The results indicate that, for same frequency interference, the SER increases gradually at the first 2 dBm, the later 1 dBm, SER increases fast until 0.47, and the interference power is proportion to the transmitting power. The microphone appears vague when the SER gets 10^-2 level, and the display screen crashes when the SER is 0.47. Signals deviation within transmitting frequency 2 MHz are easy to disturb the communication system. The strong out-band signals will reduce the communication system susceptibility, and the required disturb power is proportional to the frequency deviation extent. When the intermodulation signals vary synchronously, the power is proportional to the transmitting power, otherwise the power fit the equation of frequency. Spread spectrum or RS encoding will enhance the restrain effect of little same frequency signals, for nearby frequency interference, spread spectrum will make the system easy to be disturbed, and the range of interference power is enlarged.