Most frequency counters work by using a counter which accumulates the number of events occurring within a specific period of time. After a preset period known as the gate time (1 second, for example), the value in the counter is transferred to a display and the counter is reset to zero. If the event being measured repeats itself with sufficient stability and the frequency is considerably lower than that of the clock oscillator being used, the resolution of the measurement can be greatly improved by measuring the time required for an entire number of cycles, rather than counting the number of entire cycles observed for a pre-set duration (often referred to as the reciprocal technique). The internal oscillator which provides the time signals is called the timebase, and must be calibrated very accurately.

Keysight Technologies Inc.

Keysight's frequency counter product family includes RF, Universal, and Microwave Frequency counter products, Time-To-Digital Converters.

Marvin Test Solutions Inc.

The GTX22x0 family of PXI universal time interval counters offer many of the measurement and timing functions of high-end stand-alone frequency counters, including accumulate, auto ratio, frequency, fast frequency (GTX2220 and GTX2230 only), period, ratio, single period, test clock, time interval, time interval delay, totalize, totalize gated, totalize gated once, & pulse width.

National Instruments Corporation

Counter/timer devices provide a variety of measurement solutions, including measuring a number of time-related quantities, counting events or totalizing, and monitoring position with quadrature encoders. Counter/timer devices feature up to eight 32-bit counters and often fulfill critical timing and synchronization functions as components of complex measurement systems.


The Tektronix FCA Series frequency counter / timer / analyzer packs the functionality of a frequency counter, frequency meter and timer into one feature-rich instrument. With unprecedented resolution, you can capture very small frequency and time changes. Tektronix frequency counters and timers offer comprehensive analysis modes, including measurement statistics, histograms, and trend plots.