An ultra low-power DSP system with a flexible filterbank

A subband DSP system consuming about an order of magnitude less power than current systems doing similar tasks is presented for hearing aid and other applications. System packaging is tiny through the combination of an efficient system design and the use of deep submicron technology. A highly tuned architecture results in low system current and low voltage (1V). The system is comprised of three parts: a DSP core, an input/output processor creating frames of input speech signals, and a weighted overlap-add (WOLA) filter bank unit performing windowing, FFT and vector multiplications. The flexibility of the WOLA filter bank architecture is demonstrated through three different applications.