Research On Characteristics And Interference Of Long-wave Communication Link

Frequency below 300 kHz, with the advantages of stability and good penetrability, Long-wave has become an important means of underground communication and submarine communication. In this thesis, long-wave link characteristics and interference analysis will be studied from the following aspects:In Chapter 2, the analysis of properties of long-wave's propagation is proposed. Then, the prediction of the ground wave transmission attenuation is studied from two parts, namely the free space loss and the additional attenuation of the ground in different media. Finally, with the help of matlab, the long-wave predicted attenuation curve is obtained.In Chapter 3, we study the atmospheric noise. First of all, the formation of lightning atmospheric noise is analyzed, with the help of a large amount of observational data and mathematical formula for the number of atmospheric noise, the lightning atmospheric noise's mathematical model is established and simulated.In Chapter 4, the discussion of the artificial interference is advanced; Based on the establishment of the long-wave communication system, the analysis of the anti-interference performance of long wave communication systems is proposed as well as the determination of the best kinds of interference signal.