DESIGN AND PERFORMANCE OF A POLARITY COINCIDENCE DETECTOR

Abstract : A synchronous detector based on the polarity coincidence principle has been constructed and tested. The theory of operation is discussed with special emphasis on the influence of correlation between samples and the influence of error sources. Details of the construction are presented and test results are discussed. The present instrument works in the range of 20 c/sec to 20 Kc/sec and is capable of measuring signal to-noise ratios as low as 10 to the -4th power. It has been in constant laboratory use for several months and has proven to be a very re liable tool for the synchronous measurement of small ac signals. (Author)