Predetection Diversity Combiner

Abstract

Pre-detection diversity combining provides a number of advantages in telemetry data reception, particularly when used in conjunction with pre-detection recording equipment. These advantages include optimal ratio signal combining before pre-detection recording, pre-detection signal-to-noise ratio and threshold improvement, higher improvement in demodulated signal-to-noise ratio as compared with postdetection combining, and a number of operational simplifications, which are further enhanced when the combiner is used with dual channel receivers. Laboratory tests verify predicted performance. Additional quantitative field data is needed, but preliminary results indicate excellent performance, and no problems in maintaining phase lock have been experienced.