FPGA-based digit-serial CSD FIR filter for image signal format conversion

Abstract

This paper proposes the FPGA implementation of the digit-serial Canonical Signed-Digit (CSD) coefficient FIR filters which can be used as format conversion filters in place of the ones employed for the MPEG2 TM 5 (test model 5). Canonical representation of a signed digit (CSD) is a method used to reduce cost by representing a signed number using the least amount of non-zero digits, thereby reducing the number of multiply operations. As Field Programmable Gate Arrays (FPGAs) have grown in capacity, improved in performance, and decreased in cost, they are becoming a viable solution for performing computationally intensive tasks, with the ability to tackle applications formerly reserved for custom chips and programmable digital signal processing (DSP) devices. A digit-serial CSD FIR filter design is realized and practical design guidelines are provided using FPGAs. An analysis of the performance comparison of bit-serial, serial distributed arithmetic, and digit-serial CSD FIR filters on a Xilinx XC4000XL-series FPGA is described. The results show that the proposed digit-serial CSD FIR filter is compact and an efficient implementation of real-time DSP applications on FPGAs.