短波无线电广播信号传输干扰成因及抑制技术研究

Research on the Causes of Interference in Shortwave Radio Broadcast Signal Transmission and Corresponding Suppression Techniques

摘要

针对我台短波广播系统在运行过程中出现的邻频压制、突发宽带噪声及系统内部互调等干扰问题，结合连续3个月链路记录、频谱监测日志和随机抽样接受点场强数据，分析自然干扰、人为干扰与系统内部干扰的形成机理，并设计基于LMS算法的自适应干扰抑制方案及数字信号处理流程。研究表明，系统干扰具有明显的时段聚集性，早晚高峰累计占比约60%，受扰接收点占比约50%。方案实施后，平均信噪比由18.6 dB提升至22.8 dB，平均误码率由1.2×10^-3降至3.5×10^-4，平均噪声底降低4.5 dB，受扰接收点由21个减少至9个。结果说明，自适应滤波与FIR通道整形相结合，可有效削弱邻频信号和突发噪声对短波广播链路的影响。

Abstract

To address interference issues encountered during the operation of our shortwave broadcasting system—such as adjacent-channel suppression, burst broadband noise, and internal system intermodulation—this study analyzes the formation mechanisms of natural interference, man-made interference, and internal system interference by integrating link recording data from three consecutive months, spectrum monitoring logs, and randomly sampled received signal strength data at various points. Based on these analyses, an adaptive interference suppression scheme utilizing the LMS algorithm and a corresponding digital signal processing workflow were designed. The results demonstrate that system interference exhibits distinct temporal clustering patterns, with approximately 60% of cases occurring during morning and evening peak hours, and about 50% of affected receiving points. Following the implementation of this scheme, the average signal-to-noise ratio increased from 18.6 dB to 22.8 dB, the average bit error rate decreased from 1.2×10^-3 to 3.5×10^-4, the average noise floor was reduced by 4.5 dB, and the number of affected receiving points was reduced from 21 to 9. These results indicate that the combination of adaptive filtering and FIR channel shaping can effectively mitigate the impact of adjacent-channel signals and burst noise on the shortwave broadcasting link.

关键词

短波广播 / 传输干扰 / 自适应滤波 / 数字信号处理 / LMS算法

Key words

shortwave broadcasting / transmission interference / adaptive filtering / digital signal processing / LMS algorithm

参考文献

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