what is the frequency measure accuracy by using InfiniiVision 2000 Series?

It depends... The frequency measurement is actually 1/period. The scope measures the period and inverts the results to get frequency. The relevant spec is delta time accuracy, from the datasheet :

± (time base accuracy reading) ± (0.0016 screen width) ± 100 ps

This is essentially an RMS value, and since you have to look at two edges to make a period measurement, you need to multiply this by sqrt(2) or ~1.414

So... The answer will vary, based on the frequency of the signal and the noise (either on the signal or in the scope).

Does this help?

Al

It depends... The frequency measurement is actually 1/period. The scope measures the period and inverts the results to get frequency. The relevant spec is delta time accuracy, from the datasheet :

± (time base accuracy reading) ± (0.0016 screen width) ± 100 ps

This is essentially an RMS value, and since you have to look at two edges to make a period measurement, you need to multiply this by sqrt(2) or ~1.414

So... The answer will vary, based on the frequency of the signal and the noise (either on the signal or in the scope).

Does this help?

Al