A Very Narrow Band Filter Design and its FPGA Realization for Ranging System Based on Combined Modulation

Abstract

In this paper, a very narrow band digital filter design method and its FPGA implementation based on an IFIR filter are presented, because a filter of high sampling rate and narrow transition band is required in a ranging system combining pseudo-random code binary-phase modulation with linear frequency modulation. The performance of this filter was analyzed in detail and its FPGA realization was simulated. The results show that a digital filter designed with this method has a better filtering effect, a higher computing speed and lower FPGA resources consumption, compared with a general FIR filter.