Arrangement for measuring the lag between two timed signals by electronic correlation

摘要

An arrangement for measuring by correlation the lag produced by the transmission of a coded signal through a delaying medium and which permits a high signal-to-noise ratio and high accuracy. The received coded signal is applied to two correlators followed by a subtractor to form a discriminator circuit utilized to lock the frequency of a generator which provides two reference coded signal utilized respectively for correlation and to form an automatic tracking loop. The lag measurement is obtained by state-decoding of the transmission coded signal and of one of the reference coded signal and by pulse counting at a period sub-multiple of the bit period.