IQ-Sampling with nRF5340DK

[Johannes Kortz]

Hello,

im currently trying to setup a Project on my nRF5340 DK based on the direction finding samples from the SDK. As I understand from your tutorials an Antenna Matrix is needed to get enough I/Q-Samples for an algorithm to perform the angle calculations. My Question is if it is possible to extract I/Q-Data just from the antenna that is already on the nRF5340Dk Board and without an aditional antenna Matrix. The Example setup would be two devices that are connected and are sending CTE packets to each other and then are extracting the I/Q-Samples from these packages. I hope you understand what im trying to do. 

Best regards!

Johannes

[ketiljo]

Hi Johannes

The idea behind having multiple antennas at the receiving end is to use the IQ data to measure the phase difference between the antennas and use this to calculate the angle where the signal comes from. With only one antenna in the receiving end, you can't get the phase info and the phase will always be static. 

https://www.bluetooth.com/bluetooth-resources/bluetooth-direction-finding/

[Johannes Kortz]

Thank you for your Answer. I understood why there is the need for multiple antennas, when you want to calculate the AoA or AoD. I need the IQ-Data from the devices for a different purpose. I want to send the constant tone extension on different frequency channels and then compare the received IQ-Samples for each channel. Therefore I would only need one antenna. But I'm not sure if this setup is possible.

[ketiljo]

Have you looked at this? https://infocenter.nordicsemi.com/topic/nwp_036/WP/nwp_036/intro.html

[Johannes Kortz]

Yes I did, but again: I do not want to calculate the AoA or AoD. I dont want to perform direction finding at all. All I want to do is collect I/Q-Data via the CTE and then do this procedure on different frequencies to compare the results for a study. I just thought I could use the direction finding sample and just remove the antenna switching part. Then I would only need to find a way to perform the CTE-Exchange on different frequency channels. 

Sorry if my question was not clear enough. I have not done a lot of BLE projects before.

[ketiljo]

 https://devzone.nordicsemi.com/f/nordic-q-a/97219/iq-sampling-without-antenna-array