Power line interference attenuation in multi-channel sEMG signals: Algorithms and analysis.

Area of Science:

• Biomedical Engineering
• Signal Processing

Background:

• Electromyogram (EMG) signals are crucial for neuromuscular diagnostics.
• Power line interference (PLI) frequently contaminates EMG recordings, compromising signal integrity.
• Effective PLI attenuation is essential for accurate EMG analysis.

Purpose of the Study:

• To compare the efficacy of digital signal processing methods for attenuating PLI in EMG signals.
• To evaluate the impact of different methods on EMG signal shape and quality.
• To identify the optimal method for PLI removal in EMG recordings.

Main Methods:

• Simulated multichannel monopolar EMG signals with varying signal-to-interference ratios (SIR) were used.
• Four digital signal processing techniques were analyzed: classical notch filter, spectral interpolation, adaptive noise canceller with phase locked loop (ANC-PLL), and adaptive filter.
• The signal-to-interference ratio (SIR) of the output signals was compared for each method.

Main Results:

• The ANC-PLL method demonstrated the highest output SIR.
• ANC-PLL also resulted in the lowest distortion of the original EMG signal shape.
• Classical notch filtering, while simple, showed the lowest performance and introduced significant signal distortion.

Conclusions:

• The ANC-PLL method is superior for attenuating PLI in EMG signals compared to classical notch filters, spectral interpolation, and adaptive filters.
• ANC-PLL offers a robust solution for preserving EMG signal fidelity during interference removal.
• Accurate EMG analysis requires careful selection of signal processing techniques to mitigate PLI without degrading signal quality.