IQ Samples in Reference Period - AOA

RE: IQ Samples in Reference Period - AOA

Simonr — Tue, 30 May 2023 07:21:09 GMT

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

RE: IQ Samples in Reference Period - AOA

SRINATH — Fri, 26 May 2023 12:39:54 GMT

1. It is the phase difference obtained from reference antenna since antenna switching will not happen during reference period.
2. we have used CoreHW 4*4 antenna array with nrf52833

We agree that reference phase will not be static but phase difference should be approximately equal as of our understanding. we calculated phase difference for first 8 IQ samples (taken during reference period) and it varies a lot. what could be the cause?

We have attached our IQ sample for your reference

devzone.nordicsemi.com/.../L2-_2800_2_2900_.csv

RE: IQ Samples in Reference Period - AOA

Simonr — Fri, 26 May 2023 11:30:12 GMT

What kind of environment are you testing in here, and is this the phase difference from one antenna that differs this much, or is it between all the antennas you're using? You need to measure the phase on all antennas against the reference slot. The reference phase should not be static, as the frequency on transmitter and receiver are not the same. The phase should and will drift in a linear fashion.

Is the antenna array you've designed yourself or is it one bought by a third party for example? By default our sample projects use the Insight SiP AoA antenna array with 12 antennas, that work as expected in our experience.

Best regards,

Simon