Design and performance evaluation of a 256-point adaptive filter

In this paper an analogue c.c.d./m.o.s. implementation of an adaptive filter having high bandwidth and a large time-bandwidth product is described. The system demonstrates greatly improved performance characteristics in terms of size, power consumption, ease of use and increased bandwidth over previously published designs. Such a processor has many potential applications in communications signal processing, for the performance of tasks such as noise, echo and multipath cancellation and adaptive equalisation over both voice-band communications links (satellite, radio or 2¿¿ and 4-wire links) and high-bit-rate digital communication links. Possible applications in many other areas also exist. The main objective of the paper is to show that the prototype adaptive filter, which was based on a monolithic 256-point programmable transversal filter, behaves experimentally in a manner very close to that expected from theoretical models of an ideal adaptive filter, rather than to establish its efficacy for specific applications.