Interference-rejection properties of a quantized correlator applied to a Kineplex type of data transmission system

Kineplex typically transmits an ensemble of about 20 pulsed tones, each of which is independently phase-shift keyed in quadrature by two binary streams. The Kineplex receiver employs matched filters using differentially coherent detection. Considerations of weight, cost, and size suggest the use of suboptimum but simpler devices employing quantized correlators (QC). Each tone requires a filter, especially to reduce interference from the unwanted tones. In a time-sampled variant of Kineplex detection, the interference from the unwanted tones can be completely eliminated in principle if the tone frequencies and the number of samples satisfy certain relations. Elimination of interference results from its coherence, which allows samples of the interfering signals to be summed properly so as to cancel. Although a QC injects quantization noise, reducing coherence, a 1-, 2-, 3-bit QC gave probability of error from interference of 0.33 0.03, 0.00003, respectively, for the worst case.