How to convert real samples to I/Q data?

[wyfwfy1201]

Hi,

I am using the PXI-5105 digitizer to obtain some data. Now, without any antenna, I can collect some noise samples by it. I got the samples by the MATLAB. However, I found that the samples are real number. May I know how to obtain some I/Q data or complex number? Thanks so much.

The Figure is some samples I got from 8 channels

[Jonah_TSE]

Hi, 

I believe that the way you can recover phase information from a real signal is using the Hilbert transform.

This exists as a function in the signal processing toolkit in LabVIEW (fast Hilbert Transform), and I imagine there's also a function in MATLAB for this. 

The Hilbert transform will give you the Q or imaginary part of the data and you would use your original signal as the I or real part of the data. 

Here's a screenshot of some simple LabVIEW code that demonstrates this: 

Hope this helps. 

Regards,

Jonah Winn

NI Technical Support Engineer