September 18, 2006 -- Crafting DSP algorithms for optimum performance in hardware often requires sophisticated design techniques, such as pipelining and overclocked control logic. Such is the case for implementations using the Xilinx Virtex-4 DSP48 slice, which attains maximum efficiency when operating at its peak clock rate of 500 MHz with internal registers enabled. However, synchronizing calculations in a structure of overclocked pipeline registers can be daunting when using traditional time-domain analysis of waveforms to visualize dataflow. The z-transform is a viable alternative.

In this article, I'll present a simple, efficient methodology for analyzing high-performance DSP algorithms using the z-transform to obtain predictable results without guesswork. My examples will demonstrate quick pencil-and-paper calculation techniques of key performance metrics (such as latency) using three different structures of finite impulse response (FIR) filters, with an emphasis on Virtex-4 DSP48-based implementations.

By Luc Langlois. (Langlois is global technical marketing manager for DSP at Avnet.)