Differences between IQ Data

RE: Differences between IQ Data

Simonr — Mon, 04 Nov 2024 10:22:55 GMT

Sorry, but I don't understand what you have done differently between the two graphs you've uploaded here. You can indeed make changes to the sample offset as well if you'd like, and how to edit the IQ sampling is described in our Direction Finding whitepaper here: https://docs.nordicsemi.com/bundle/nwp_036/page/WP/nwp_036/intro.html

Best regards,

Simon

RE: Differences between IQ Data

trgyada — Fri, 01 Nov 2024 10:37:15 GMT

Hello, yes, I use it on both the receiver and transmitter side. Also, as you said, I am constantly changing the signal PHYs and slot times and trying to take samples. I am not using any tools other than the system provided by Nordic. After taking various samples, I am trying to visualize all IQ data with Python for analysis. However, during these attempts, I encountered the situation I mentioned. Frankly, I am curious about the reason for this. Also, apart from sampling spacing and switching spacing, I am questioning whether an offset structure for sampling can be made on the Nordic side. For example, sample space 2us, switch space 2us and sample offset 1 us. According to my guesses, instead of taking data from the moment it is switched, it is necessary to take samples with a certain offset in the existing sampling interval.

Best Regards.

RE: Differences between IQ Data

Simonr — Fri, 01 Nov 2024 10:28:57 GMT

Are both of your kits nRF5340 DKs or are these two slightly different boards? I assume you're using the CoreHW AOA antenna as a receiver/locator, correct? Do you have the same exact application running on the two devices or are you using different configs, board files or overlays that might be adding some issues here? The second graph seems to be offset somehow indeed, and that could be due to a mismatch of PHY, sampling slots or similar I think. But I need some more information on what exactly is being measured here. Is this just raw IQ data or have you run it through an AOA algorithm on the receiver side?

Best regards,

Simon