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How do you create file to create FMCW waveform with FMCDAQ2?

Question asked by etroy on Sep 13, 2016
Latest reply on Sep 14, 2016 by CsomI

I am trying to use the FMCDAQ2 to create a FMCW signal. The goal is 5 MHz sweep at 300 MHz with a sweep rate of 1 ms with a triangular waveform. I have created an IQ file that I think is what is correct for the design, but it does not create the correct waveform. I took the file and loaded it into a simulator that creates a waveform from an IQ file, and it did create a waveform that spans 300 to 305 MHz and looks good. I use a clock frequency of 1000 Msps, since it is apparently very difficult, if not impossible, to change the clock frequency when using the FMCDAQ2 with the ZC706 board which is my setup. I don't understand what I am doing wrong. I do not get an error on the system, and I do get a waveform that is centered at about 300 MHz, but it is not an FMCW waveform. I have checked with both the A/D converter an iio scope and with a regular spectrum analyzer.

The actual file is over 50 MB, so I am just attaching the first few hundred lines. There is obviously something that I am doing wrong.

I also tried putting 4 columns, IQ, IQ, with all columns separated by commas to program both of the D/A converters, but that gives me an error message that the file is not of the correct format.

(I will attach the full file if anyone is interested.)