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How measure two-tone FFT?

Hi. Please tell me what VI or toolkits can measure parameters  two-tone FFT?

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Message 1 of 6
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Any of the spectral measurement or FFT functions/VIs may be useful.

 

What are the frequencies involved? What is the sampling rate of your measurement equipment? Do the tone frequencies change during a meaurement?

 

Lynn

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Frequency - about 30 MHz. Sample rate - about 200 MS/s.

 

I analyze Sound&vibration toolkit but i don't find any VI's which can measure exactly this parameters. Maybe there are any examples in which these parameters are calculated.

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LabVIEW is a programming language. While you can certainly program a two tone measurement, it may be unlikely that you will find something pre-made which does exactly what you want.

 

If both f1 and f2 are ~30 MHz, some of the products (2*f1 + f2) will be close to the Nyquist limit. It may be important to have a good anti-aliasing filter if there are significant components above Nyquist.  As long as all the signals meet the Nyquist criterion, you should be able to make the measurements. You may need large sample sizes to get enough data to do what you want.

 

You might also check the RF Measurement Devices and the USRP Software Radio Boards to see if someone there has done something which might be useful for you.

 

Lynn

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Message 4 of 6
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It's all clear. But is LabView has exactly VI's (or any software) to measure parameters?

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LV has DAQmx for controlling the data acquisition device (assuming it it an NI device). It has FFT functions to do the Fourier transform. It has a Peak Detector VI to find peaks in the spectrum.  It has basic numeric functions for calculating relative amplitudes. What else do you need?

 

Lynn

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