Digital filtering in FPGAs

While the general purpose logic elements of the field programmable gate array (FPGA) appear to be unlikely candidates for implementing the multiply-intensive operations of digital filtering, the application of distributed arithmetic (DA) techniques turns the FPGA into a worthy contender. Indeed, in some important filter applications the Xilinx 4000 family of FPGAs offers superior performance over the fastest fixed point DSP microprocessors. A brief description of DA processing is presented to provide some background for the filter design examples that are presented. A simple FIR filter will serve to establish the design concepts, and a two dimensional Sobel edge detector will serve to illustrate the performance capabilities of this approach