Comments on "New algorithm for measuring 50/60-Hz AC values based on the usage of slow A/D converters" and "Measuring of slowly changing AC signals without sample-and-hold circuit"

In this correspondence, the results of the original paper are commented on [ see ibid., vol. 49, p. 166-71, 2000 and vol. 49, p. 1245-48, 2000]. It is shown that conditions when the averaging formula is claimed to be valid are not correct, and that synchronization on the signal period level is required. Correction of these conditions is given.