Lower ionosphere nonlinearity study on high frequency time service signal in China

The multiple non-linear interaction theory model of high-frequency (HF) electromagnetic wave and Schumann Resonance (SR) is constructed on the basis of ionosphere cross modulation. The global SR distribution, particularly the phase variation effect on the modulation depth of HF waves and SR, is investigated. Results show that modulation depth is not proportional to the interaction distance under the condition of multiple interactions. A new SR observation method is proposed, and the observatory system is designed on the basis of theoretical research. China short-wave time service signal called BPM is received and demodulated. The first four spectral peaks of SR are obtained at 7.8, 14, 20 and 26Hz. The multiple non-linear interaction theory model of HF electromagnetic wave and SR is proven by the experiment. Signal analysis comparison is conducted and recommendations for future work are proposed.