Frequency resolution of NI 9234

[marcos88]

Hello dears,

In the data sheet of NI 9234 (a four-channel dynamic signal acquisition module), it is specified that the data rate range (Fs) mínimum is 1.652 KS/s and the maximum is 51.2 KS/s.

How these data and / or others of the data sheet are linked, with the frequency resolution of the acquirer.

Thank you.

Marcos 

[Cavarval]

Hello Marcos,

Do you mean the frequency resolution in a frequency domain measurement, like an FFT?

If so, the following documents should help:

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019MIYSA2&l=en-US

http://zone.ni.com/reference/en-XX/help/370371K-01/smtlvconcepts/guid-cce625b8-0319-465b-b5f7-06f878...

https://zone.ni.com/reference/en-XX/help/373398C-01/svaconcepts/svincreasefreqres/

Sample rate does not affect resolution on its own, but it does indirectly. Frequency resolution is only affected by the measurement time of the signal, however, since the measurement time is given as the ratio of the number of samples acquired and the sample rate. 

What sample rate defines directly is what is the largest frequency you can acquire. In an FFT, for a given sample rate, you can increase the resolution by acquiring more sample, hence increasing the measurement time.

Does this help?

Regards,

[Cavarval]

Also, I just noticed this is duplicate from this thread.

https://forums.ni.com/t5/Multifunction-DAQ/Frequency-resolution-of-NI-9234/m-p/3906522

Regards,