How do i capture high frequency signal using NI DAQ card?

[Blessing_Star]

Is it possible to capture High Frequecy (2.5MHz) signal using NI DAQ (USB-6363 / PXI-6259) or any other DAQ/Hardwares?

Appreciate your response.

[SunshineDesign]

No you can not capture the 2.5MHz signal with the DAQ devices mentioned. You must have a sample rate at least 2 times higher and preferrably 5 to 10 times higher sample rate than the frequencyu being measured. This is due to Nyquist criteria for digitization. The USB DAQ mentioned only had a 1MS/s sample rate.

[Blessing_Star]

I'm sure that it needs atleast 5MS/s/Channel to acquire the actual pattern. I know that there are Scopes & Spectrum Analzyers can capture such high frequency signals.

I'm trying to find out, Is there any NI Hardware Device can acquire such high frequency signals?

Thanks

[JÞB]

Yes most of the digitizers work up at those frequencies

[SunshineDesign]

Some of the PXI Scope cards have sample rates high enough to measure up to VHF frequencies. I used some of them to measure HF transceivers to 30MHz. Try to get at least 12 bits of digital depth so you can measure enough dynamic range. 8 bits can give higher sample rates, but only measures at best about 30 to 35dB of dynamic range.