High-speed digital filtering: Structures and finite wordlength effects

This paper is a study of high-throughput filter structures such as block structures and their behavior in finite precision environments. Block structures achieve high throughput rates by using a large number of processors working in parallel. It has been believed that block structures which are relatively robust to round-off noise must also be robust to coefficient quantization errors. However, our research has shown that block structures, in fact, have high coefficient sensitivity. A potential problem that arises as a result of coefficient quantization is a periodically time-varying behavior exhibited by the realized filter. We will demonstrate how finite wordlength errors can change a nominally time-invariant filter into a time-varying system. We will identify the block structures that have low coefficient sensitivity, and develop high-speed structures that are immune to the time-varying problems caused by coefficient quantization.