AnsweredAssumed Answered

ADRV9375 custom waveform generating and sampling

Question asked by Moritz on Jul 31, 2018
Latest reply on Aug 16, 2018 by Moritz

Hello,

I work with ADRV9375 on the ZQ706 motherboard. Set which I use, operates on image manager from windows-base TES and DPD GUI applications. I try to generate custom (digital modulated) waveforms using Matlab and load it to AD9375 by DPD GUI. DPD GUI has Waveform Duration limitations 1-10 ms what forces setting 100-1000 times higher Sample Rate [MSPS] parameter than number of samples in IQ tab-separated text files I generate. Spectrum analizer demodulates with Symbol Rate limited to 50 Hz - 10 MHz.

For example: I generate QPSK waveform (19200 symbols), , using Matlab functions qammod(), rcosdesign(), upfirdn() with filter parameters: SamplesPerSymbol = 10; span = 20; rolloff = 0.22. It gives a file with 192191 IQ samples (10 samples per constellation symbol), which I load via DPD GUI. To satisfy DPD GUI Waveform Duration I set Sample Rate 80 MSPS and load waveform to the ADRV9375. Now my question:

How exactly should be constructed waveform in the file and how it is reconstructed by DPD GUI? I get EVM = 3-5% (EVM = 1-1.5% required) what seems to be an effect of some discontinuity during periodic rendering of the waveform. Is there some example script for generating digital modulated waveforms or some description how to construct custom waveforms?

 

Thanks in advance,

Moritz.

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