Abstract: PONS comprises a transform coder and decoder for discrete time electrical signals, in particular acoustic signals. The PONS coder utilizes an integer coefficient transform coder which is not frequency based, which requires almost exclusively fast integer arithmetic, and which spreads incoming signal energy nearly as evenly as possible among coefficients in the transform domain. The PONS coder also has the property that the magnitudes of transform domain coefficients vary by less than about an order of magnitude, so that the PONS coder dispenses completely with time-varying bit allocation. PONS uses only the quantization step to achieve significant compression. Energy spreading also permits reasonably accurate signal reconstruction when significant numbers of transform coefficients are lost or corrupted.

Abstract: WAM.TM. is a new method of digitally coding and decoding acoustic signals for data compression and noise reduction. The method comprises constructing a filter bank using wavelet transforms of a basic filter impulse function to represent the response of the mammalian cochlea. Data compression is obtained by truncation of a discrete representation. Reconstruction relies on the theory of frames and produces a reconstruction method and apparatus based on irregular sampling methods which produces good quality results in a very few stages. Actual reconstructions show very good data compression and noise reduction performance.