IQ Samples in Reference Period - AOA

[SRINATH]

Hi,

Iam working on direction finding using AOA technology. I have nrf52833 board integrated with Core-hw 4*4 antenna array which acts as locator. The slot duration I have set is 2 us .That is 2 us  switching and 2 us sampling period. Iam trying to do phase compensation with the average phase difference in reference period. From this attached context (https://devzone.nordicsemi.com/f/nordic-q-a/75446/aoa-iq-samples-sampling-time-and-their-correction) My understanding is that the phase angles in the reference period (i.e for first 8 samples) can be different, but its phase difference should be regular or equal. In my case the phase difference calculated in reference period is in the range of -102 to 107. Can you suggest what is the issue for getting the reference phase differences in this range or unequal values.

How can it be corrected?

[Simonr]

Hi

An unstable reference period is usually expected in a noisy environment. The results need to be filtered, and you should drop the ones with large differences form the mean value. It would be best to do initial testing in a noise-free environment (outside for example) to ensure that this is not a HW issue.

You can also try shortening the slots as much is the RF switch allows to get better results.

Best regards,

Simon