Transversal filter techniques for adaptive array applications

It is pointed out that the broadband performance of present jamming cancellation equipment is often limited owing to the presence of effects which cause phase and amplitude distortion across the band. Some of these effects are discussed in connection with the present investigation. It is shown that cancellation performance can be improved by making use of an adaptive transversal filter (ATF). In order to compensate for the effects of array mismatch, positive or negative delays are required. This can be achieved by placing a single delay line in the primary channel equal to half the total delay in the transversal filter. This approach requires an even number of delay sections in the transversal filter to allow cancellation of any undistorted signal. The maximum delay required in the transversal filter will normally need to be similar to the maximum multipath delay.