measuring frequency with counter or analog input?

[kzamora]

I have some frequencies which I need to measure. Some signals are digital and some are analog.

I have a PXI-6040E DAQ which has both counters and analog inputs. 

I heard that you can measure higher frequencies with the counters than with analog inputs.

What is the range of frequencies an analog input can determine versus a digital counter? 

Where is the cutoff that you must absolutely use a digital counter to determine the frequency?

Is the cutoff different for different DAQ cards? Or is generally the same.

[Dennis_Knutson]

Have you looked at the specs for the device? The max sample rate and the max counter input will be listed there. The max frequency for an analog input is based on nyquist sampling theory. Are you at all familiar with? It states your sampling frequency has to be at least twice the frequency you are measuring.

Since each device might have a different max sample rate, your last question is answered.