A narrowband active noise control system with frequency mismatch compensation

Narrowband active noise control (ANC) systems enjoy good performance where sinusoidal signals dominate in the primary noise, on condition that a reference signal of the same frequencies with the primary noise is given. However, frequencies of the reference signal provided by nonacoustic sensors are usually different from that of the primary noise due to temperature changes, aging, etc. Such frequency mismatch (FM) will make the narrowband ANC systems unable to suppress the primary noise effectively, even render them useless. In this paper, we propose a new narrowband ANC system that integrated with a frequency estimation subsystem. The frequency estimation is obtained from a spectrum computation based on an adaptive linear prediction filter. The estimated frequencies are used by the cosine signal generator to produce a more accurate reference signal to the main controller, thus the performance deterioration caused by FM can be mitigated. The effectiveness of the proposed system has been confirmed by numerous simulations.