Adaptive Notch Filter for Eliminating Power Frequency Interference in Communication Systems

Employing adaptive notch filters to eliminate power frequency interference in communication systems represents an effective solution. When analyzing the filtering performance of single-frequency notch filters, we focus on critical parameters such as the LMS algorithm's step size factor, frequency difference between desired signal and interference, and amplitude/phase characteristics of reference inputs. Furthermore, using dual-frequency interference as a case study, we examine the properties of cascaded multi-frequency notch filters. The implementation demonstrates that after two-stage filtering, signals can be accurately recovered with stable error convergence. The LMS algorithm adapts filter coefficients recursively using the formula w(n+1) = w(n) + μ·e(n)·x(n), where μ represents the step size controlling convergence rate. Through detailed discussion of these key aspects, we gain deeper understanding of adaptive notch filter applications for power frequency interference cancellation in communication systems, including practical implementation considerations for real-time digital signal processing environments.