An analysis of the effects of jitter in data acquisition on synchronous averaging

A synchronously averaged signal, acquired in real time using an A/D converter, a package of service routines and a computer, can be corrupted if precautions are not taken to minimize imprecise timing (jitter). The effects of jitter on the recovery of a signal from noise by averaging is discussed. Two cases are examined. In the first case, the jitter is the result of frequency mismatch between the acquisition repetition frequency and the signal frequency. In the second case, the jitter is due to a random phase shift present in each of the acquired waveforms. Both cases result in a reduction in magnitude and a variation in latency. A detailed analysis is given deriving several statistical descriptors. It is established that these descriptors are closely related to the characteristic function of jitter. Special cases where jitter obeys the Gaussian and uniform distributions are examined. A simple technique for determining the mean and standard deviation of the jitter is also given by example