1. A signal processing device for processing a portion of an input signal, the input signal portion having a predetermined size, the signal processing device comprising: output selection means for selecting one of a first output signal and a second output signal as a final output signal based on a predetermined threshold; first output signal generating means for computing the first output signal from the input signal portion based on a predetermined signal transform algorithm; algorithm selection means for selecting one of a plurality of signal transform algorithms as the predetermined signal transform algorithm in the first output signal generating means; a neural network operating concurrently with the first output signal generating means and generating the second output signal from the input signal portion based on a current set of learned weighted coefficients, the neural network comprising: an input layer of neurons having a number of neurons equal to the predetermined size of the input signal portion; an output layer of neurons generating the second output signal, each neuron of the output layer connected to each neuron of the input layer; the current set of learned weighted coefficients, wherein each output layer neuron receives an output from each one of the input layer neurons by multiplying an output of each one of the input layer neurons by one of the current set of learned weighted coefficients; learning means for generating the current set of learned weighted coefficients based on a comparison of the first and second output signals, the learning means operating concurrently with the first output signal generating means; storage means for storing a plurality of sets of learned weighted coefficients, each set of learned weighted coefficients corresponding to one of the plurality of signal transform algorithms; and setting means for setting one of the plurality of sets of learned weighted coefficients as the current set of learned weighted coefficients based on the signal transform algorithm selected by the algorithm selection means.