Time-frequency instrumentation Part 1

The frequency of a signal is a measure of the number of oscillations in a unit of time. The hertz, its unit of measurement, corresponds to the number of oscillations in one second. In the real world, signals do not have stable, constant frequencies, not even the reference oscillators used as clocks. The aim of this article is to present the measurement techniques associated with the time-frequency domain, in order to compare a signal with another reference signal in terms of frequency or period, to determine a time interval with accuracy, and to ensure in all cases a metrological measurement with the best possible performance.

Signal quality can be characterized in either the time or frequency domain. Time-domain counting techniques will be presented in the first section. The second part will be devoted to specific frequency-domain instruments.