For high frequency measurements with two counters, you measure one pulse of a known width using your signal and derive the frequency of your signal from the result.

Note Counter 0 is always paired with Counter 1. Counter 2 is always paired with Counter 3.

For this measurement method, the device uses first counter to generate a pulse of duration T. The device routes this pulse to second counter. The second counter then counts the number of periods (P) of the signal-to-measure during the pulse.

If the frequency of the signal-to-measure is fx, the duration of the pulse is given by the following equation:

T = P f x

Solving for fx returns the frequency of the signal-to-measure:

fx = P T
Figure 32. High Frequency with Two Counters