Tone Jammer Cancellation in a Tapped-Delay Line Correlator

A method for determining the optimum tap weights to cancel one or more tone jammers in a tapped-delay line correlator is described and demonstrated to achieve almost perfect cancellation when continuous tap weight values are employed. When the tap weights must be quantized, as in the case of a digital tapped-delay line, it is shown by computer simulation that five bits of uniform quantization are sufficient to reduce the degradation in output signal-to-interference ratio to less than 3 dB when the jam-to-signal ratios are as large as 50 dB. Since the optimum tap weights are critically dependent on the jamming frequencies, a method of broadening the cancellation region is discussed, as is a technique for estimating the jamming frequencies from the signals observed at the taps.