中文摘要：

针对工频通信系统中背景电流大于调制信号的情况，提出以最小二乘法进行背景电流拟合的设想。针对调制信号湮没在噪声中的情况，采用小波分析、时频分布以及短窗自相关3种信号提取方法，介绍3种方法的原理、特点，并做仿真试验，对仿真结果进行比较、分析，确定小波分析方法为信号的有效提取方法。最后采用实际工程数据进行检测，结果表明最小二乘法与小波分析方法相结合是检测强干扰中有用信号的有效方法。

英文摘要：

Least-square principle was brought forward to fit the background current towards the problem that the background current was far greater than the communication signal. Then, wavelet analysis, time-frequency analysis and self-correlation algorithm were introduced for the problems that the modulated signals were flooded by yawp. The theory and the characteristic of these methods were introduced in detail and the simulation was done. With comparing and analyzing the simulation results, it ensured that the wavelet analysis was the effective method in signal distilling. At last, the practical project data was adopted and the result was satisfying. All these proved that the plan of combining least-square principle and wavelet analysis was an effective method in useful signal detection.