Low complexity multi-rate IF sampling receivers using CIC filters and polynomial interpolation

This contribution deals with a fully digital multirate radio receiver with IF sampling. Timing correction and sample rate conversion are performed by a polynomial interpolator. By performing interpolation prior to matched filtering a significant reduction in complexity may be achieved. Low degradations are attainable when the receiver design parameters are carefully chosen. If this is not possible, digital anti-aliasing filters are required. We investigate the computational complexity and BER performance when efficient cascaded integrator-comb (CIC) filters are employed to perform anti-aliasing. We show how some of the side-effects of CIC filters may be overcome and how CIC parameters may be selected to provide acceptable BER degradations for all symbol rates.