TIME DISCRETE FILTER COMPRISING UPSAMPLING, SAMPLING RATE CONVERSION AND DOWNSAMPLING STAGES

摘要

A time discrete filter comprises a sampling rate converter provided with an input and an output, and a down-sampler having a down-sampling factor nd. The time discrete filter further comprises an up-sampler having an up-sampling factor nu, whereby the up-sampler is coupled to the converter input, and the converter output is coupled to the down-sampler. It has been found that if a sampling rate conversion operation is preceded by an up-sampling operation and only after the conversion is followed by a down-sampling operation to a wanted sampling frequency, that then the complexity in terms of the ultimate number of calculations, in particular multiplications and additions, is reduced. This leads to a decrease of the number of instructions per second which is a measure for the complexity of a Digital Signal Processing (DSP) algorithm. In addition this leads to an associated decrease of power consumed by a DSP, such as applied in for example audio, video, and (tele)communication devices, as well as radio and television apparatus.