Design of a frequency tracker for laser anemometer measurements

The laser anemometer tracker discussed in the present paper was designed on the basis of a hybrid (analog-digital) computer simulation. The results of the simulation showed that the tracker should be a rate of change of phase detector, rather than a zero-crossing detector, that the tracker should posess some means of validating a measurement, that it should be fast enough to follow the phase fluctuations of the anemometer signal and should have some memory of the last successfully detected reading. Tracker operation should be as automatic as possible. A second-order phase lock loop chosen for the basic circuit is diagrammed.