The Spec Hack So, let’s put it all together.

Why oscilloscopes make great frequency counters. Their differences in the context of frequency analysis derive from their front-end, signal-conversion approach. For instance if you were designing a system that uses pulses from something like an photo-interrupter, an oscilloscope would easily tell you the frequency of the pulses and this could be used to determine speed. The digital oscilloscope also has added DSP, and gains much higher bandwidths. As luck would have it, the trigger circuitry of a scope often has comparators built into the signal path (think “edge trigger”). With some planning, it’s not difficult for oscilloscope designers to include a frequency counter built into the oscilloscope.

As mentioned above some Counters only measure frequency, while some which are usually called Universal Counters can offer more features which you may or may not need. So, a frequency counter can simply use the oscilloscope’s trigger signal path instead of the acquisition signal path and get a higher fidelity edge.