Patent ID: 8947071
Filing Date: 2015-02-03
Classification: G01L,G01R

Abstract:
1. A method of determining a frequency of a signal train using a digital counter, a clock oscillator and a latch, the signal train having a series of signal pulses, the counter being driven by the clock and the method including the steps of: i) sampling the signal train over a first signal portion and a second signal portion of the signal train, the first and second signal portions having a predetermined number of signal pulses and the second signal portion overlapping with the first signal portion; ii) loading clock counts from the digital counter into the latch when triggered by start and finish edges of the first and second signal portions of the signal train; iii) subtracting clock counts latched by start edges from clock counts latched by finish edges of the first and second signal portions to obtain periods of the first and second signal portions; iv) determining first and second average periods for the first and second signal portions of the signal train; and v) determining the average of the determined average periods.