Analysis and Correction of Frequency Error in Electronic Mufflers using Narrowband Active Noise Control

This paper analyzes the performance of an electronic muffler using narrowband feedforward active noise control (ANC). The effect of frequency error between the engine noise and the internally-synthesized reference signal on the performance of the muffler is analyzed. Theoretical analysis shows that the achievable noise reduction is decreased for increased frequency error. An electronic muffler is built and real-time experiments are performed to verify theoretical analysis and computer simulation results. Two solutions are developed to minimize the effect of frequency error and maintain consistent noise reduction.