Simulation study of variable step-size LMS algorithm in frequency domain for de-noising from MRS signal

Magnetic Resonance Sounding (MRS) equipment for groundwater exploration has high receiving sensitivity, and it is vulnerably affected by high-level power-line harmonic when worked near the city and village. In order to effectively extract the weak signal, variable step-size LMS algorithm in frequency domain is studied to eliminate noise based on the principle of adaptive noise cancellation. Simulation results show that the algorithm can increase the signal to noise ratio more than 10dB, and the fitting error of parameters is about 10% in the condition that the frequency offset between signals and power-line harmonic is greater than 7Hz and with different SNR and water content. Therefor the variable step-size LMS algorithm in frequency domain can obtained better de-noising effect and parameter extraction accuracy.