Sample rate conversion technology in software defined radio

In this paper, a reconfigurable integer factor sample rate converter is proposed for software defined radio (SDR) receivers. A general principle for digital filter design in sample rate conversion (SRC) in SDR receivers can be summarized as that implementation efficiency is emphasized in the front stages, while high performance must be emphasized in the back stages. Based on this principle, a Cascaded Integrate Comb (CIC) filter with factor-16 down sampler is used to realize large-factor and multiplier-free decimation in the front stage, while a multistage decimator is implemented together with the CIC filter to provide finer integral down sample rate. The multistage decimator is consisted of three stages, with each stage serving as a factor-2 down sampler. The Nyquist filters are used as anti-aliasing filter in the first two stages, and the linear phase Equiripple filter is used in the last stage. In the end, the results of the sample rate conversion in SDR receiver are provided in this paper.