Design of an improved interpolation filter using a trigonometric polynomial

The use of interpolation for the adjustment of timing offset in digital modems has attracted increasing attention. We recently announced a novel interpolation method which, instead of approximating the continuous-time signal with a conventional polynomial and computing the synchronized samples using a Farrow structure, uses a trigonometric polynomial. Simulation results indicate that improved performance, reduced computational delay and, in most cases, simplified hardware can be achieved. In this paper, we formulate our method in terms of a digital interpolation filter. We then show that with a slight modification of our original method, the interpolation filter based on the trigonometric polynomial can achieve a desired frequency response