Digital Resampler Based on Farrow Filter

Farrow filters allow to design universal resamplers for fractional delay correction and sampling rate conversion. The use of cubic Lagrange interpolation in the Farrow filter does not allow to provide high performance resamplers due to the narrow processing band (less than 0.4F<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</inf>) and the high side lobes level of the frequency response caused by the non-smooth interpolator impulse response. The new Farrow filter structure based on the 3rd, 5th and 7th order Hermite splines and high order wide band differentiator filter is proposed in this paper. Proposed filters increases of the processing bandwidth up to 0.8F <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</inf> by polynomial order increasing with additional restrictions on the derivative continuity in interpolation nodes. The proposed filters structures are optimized to minimize the multiplications for polynomial coefficients calculation. In the experimental part Farrow filter was applied to the 5G wideband signal interpolation. Farrow filter with fixed-point design can be used with such optimizations as data bit length reduction. Such techniques can reduce occupied crystal area and power consumption with controllable performance degradation.