Highly oversampled subband adaptive filters for noise cancellation on a low-resource DSP system

A real-time subband adaptive noise cancellation system on an ultra low-power miniature DSP system is implemented. The system is targeted at personal communication devices where the speaker may be in a noisy environment. The system is implemented on an ultra low-power DSP system that incorporates a DSP core and an oversampled WOLA filterbank. Pre-emphasis filters are used to increase the convergence rate of a leaky LMS algorithm in the oversampled subband implementation. System performance is also improved relative to a fullband implementation due to benefits arising from using subband adaptive filters instead of fullband filters. A 10 dB reduction of noise power is achieved in tests using various noise conditions. The entire DSP system consumes 2.1 mW and can be realized in a package size of 6.5 x 3.5 x 2.5 mm.