PHASE-LOCKED SAMPLING OF A PERIODIC SIGNAL

摘要

A method for phase-locked sampling measurement of a periodically varying quantity. The samples are designated g(I) ... g(I-n) and may comprise one complete period or a half of one period. The method involves adapting the sampling frequency and the sample position in relation to the quantity to be measured such that phase locking is attained, and this is done by controlling the time interval between sampling. Whether the sampling frequency needs to be increased, left unchanged or be decreased, depends on a number of decisions depending on the values of samples g(I) and g(I) - g(I-n). A device for carrying out the method is also described.