LAUNCHXL-CC26X2R1: The way to identify which antenna is sending the IQ signal

Cherry Zhou

Mastermind 22235 points

Part Number: LAUNCHXL-CC26X2R1

Device: CC26X2R1+BOOST-AOA as coordinator

Use A1.1 1.2 1.3 to collect signals from another cc26x2 as coordinator.

The python collection code and firmware code are modified with the following parameters:

Iq data is currently operational and collected, but it cannot match iq data with the antenna.

What does sample_idx= 46 mean in the figure above?

Iq transmitted by different channel should also not be able to calculate AOA.

The customer would like to know how to process iq data then can identify which antenna data is.

Could you please help to check it? Thanks a lot!

Best Regards,

Cherry Zhou

over 4 years ago

0 Nathan Block over 4 years ago

TI__Mastermind 37805 points

Hi Cherry,

Is there a reason to believe the pattern isn't what's specified in the python code (1, 2, 3, 1, 2, 3....etc)?

You can verify this during run-time using the instructions here:

https://dev.ti.com/tirex/explore/content/simplelink_academy_cc13x2_26x2sdk_5_20_02_00/modules/rtls_toolbox_ble5/ble_aoa/ble_aoa_locator.html#step-2-ndash-verify-the-antenna-switching-pattern-used-by-the-locator

Best,

Nate

0 Cherry Zhou over 4 years ago in reply to Nathan Block

TI__Mastermind 22235 points

Hi Nate,

Thanks for your reply.

The receive antenna is converted by modifying the python code according to the document.

And the customer just would like to know how to distinguish the data from the three antennas, could you please help to distinguish them?

Thanks a lot!

Best Regards,

Cherry

0 Nathan Block over 4 years ago in reply to Cherry Zhou

TI__Mastermind 37805 points

Hi Cherry,

I think it should be indicated by the sample_index and the "aoa_ant_pattern"

So, for this example, the first sample comes from antenna 1, the second from antenna 2, the third from antenna 3, the fourth from antenna 1...etc

I am confirming this with our team AoA expert now.

Update

I have reviewed this with our team AoA expert, who has given me the following link which describes which samples to use and which to discard. Once all the irrelevant samples are discarded as described in the link, the order is the same as above (first relevant sample is antenna 1, second is antenna 2, third is antenna 3, fourth is antenna 1...).

dev.ti.com/.../localization-index-cc13x2_26x2.html

Best,

Nate

0 Cherry Zhou over 4 years ago in reply to Nathan Block

TI__Mastermind 22235 points

Hi Nate,

Thanks for your reply!

The customer has figured out this problem. And he also would like to know the following 2 questions:

1. The Bluetooth protocol uses 37 channel switches to transmit signals, but iq between different channels cannot be calculated with the iq signal. Is it possible to modify it to only transmit on a fixed channel for easy computation?

2. About Sample Rate: The sample rate set in the python script is 1 MHz, whereas the actual acquired IQ data is 150 IQ per second. How to explain it?

Thanks a lot!

Best Regards,

Cherry

0 Nathan Block over 4 years ago in reply to Cherry Zhou

TI__Mastermind 37805 points

Hi Cherry,

For separate questions, please open a new thread. This makes it easier both for us to track our metrics and for people later looking for the same answer to find it rapidly. I'll be happy to answer as soon as you copy this question into a new post.

Best,

Nate

Bluetooth®︎

Bluetooth forum

LAUNCHXL-CC26X2R1: The way to identify which antenna is sending the IQ signal