# What's the difference between measurement resolution and digits per second in time measuring devices

In time/frequency counters/analyzers in technical specifications you can almost always find resolution and digits per second values next to each other. What is the difference?

• Give an example. "Digits per second" doesn't sound right. Dec 13, 2017 at 20:13
• Digits has nothing to do with resolution, resolution does. Dec 13, 2017 at 20:25
• @Transistor pendulum.se/wp-content/uploads/2017/01/… it s confusing to me too Dec 13, 2017 at 20:44
• @Trevor Huh... what do you know? There is a thing called "Digits/second"... -looks up digits per second on Google-... AH HA! You're talking about "Symbols per second" or "baud/sample rate".
– user103380
Dec 13, 2017 at 20:51
• @glen_geek nope, in any case of a spectral estimator (like the FFT), you'd get variance in your estimation – so, no, there's no free lunch, and you can't get 12 significant digits with a clock source only exact to (at most, with the most expensive add-on) 9 digits. Dec 13, 2017 at 22:35

Carmel Instruments products page for time interval analyzers / frequency counters explains it as follows:

Freq. Resolution - The resolution for Frequency Average and Period Average functions is dependent on the single-shot time resolution and the duration of the measurement (effective gate time). It is easier to specify it as a number of digits per second. For example, 12 digits/s means that you will get 12 digits of frequency resolution with a 1 second gate time, or 9 digits in 1 millisecond. If the signal input is 1 MHz, 9 digits of resolution translates to 0.001 Hz resolution.

So some of the comments were on the right track. I note that this specification gives no indication of accuracy and, as posted in the comments.