1. A microprocessor structure for performing a discrete wavelet transform operation, said discrete wavelet transform operation comprising decomposition of an input signal vector comprising a number of input samples, over a specified number of decomposition levels j, where j is an integer in the range 1 to J, starting from a first decomposition level and progressing to a final decomposition level, said microprocessor structure having a number of processing stages, each of said stages corresponding to a decomposition level j of the discrete wavelet transform and being implemented by a number of basic processing elements, the number of basic processing elements implemented in each of said processing stages decreasing by a constant factor at each increasing decomposition level j.