What is the phase relationship between two PoAs on the dw3220？

Wireless Connectivity Ultra-Wideband
1

this is my config

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and I use dwt_readdiagnostics() to get diagnostic values.

but most time stsPOA - sts2POA does not equal to pdoa.

what’s wrong with that?

2

There is a phase rotation that occurs internally when calculating PDoA between STS1 and STS2 using mode 3.
Change to Mode 1, and use IP_POA - STS_POA.
Or if you need to use mode 3, you can set the CIA_ADJUST register = 0.

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3

thank you for your reply. I did what you said. and it still didn’t work.
This is the waveform I got, with the green line representing pdoa and the purple line representing stspoa - sts2poa. As can be seen from the graph, sometimes the two lines coincide but sometimes they do not coincide, and when they do not coincide, the trend of change is the same.

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4

Can you share the code you are using to convert the data?
You need to calculate the two’s complements as well.
Here is a code snippet to convert the data.

"""
poa_convert.py
===
Provides three functions to convert raw PoA register values to Phase Difference in degrees on DW3000
Copyright Qorvo, Inc. 2023
All rights reserved
"""
import numpy as np

def convertPDoA(num):
    answer = int(num) / (1 << 11) * (180 / np.pi)
    return answer

def twc(val, nbits):
    s_bit = 1 << (nbits-1)
    return -(val & s_bit) | (val & (s_bit-1))

def convertPoA(num):
    phase = int(twc(num, 14)) / (1 << 11) * (180 / np.pi)
    return phase

def main():
    # Example PDoA and PoA values
    pdoa = [502, 96, 152, -112, 24, -822, -1266, -2466, -1862, -2686, -3346, -4448, -2442, -1180, -232, 1684, 2428, 2996, 4024, 4662, 5514, 5044, 5330, 4918, 3120, 1342, -630, 344]
    sts1 = [10444, 13510, 3192, 13200, 10624, 6004, 1152, 13894, 894, 2136, 4376, 12944, 3384, 16034, 5406, 15508, 1008, 10894, 3226, 3184, 2386, 6378, 2880, 3098, 4124, 4470, 5486, 15308]
    sts2 = [6426, 13414, 3040, 13312, 10600, 10342, 2418, 16360, 2756, 4822, 11238, 1008, 5826, 830, 5638, 13824, 14964, 4382, 15586, 14906, 13256, 1334, 13934, 14564, 1004, 3128, 6116, 14964]

    print('PDOA raw: ', pdoa)
    print('STS1 raw: ', sts1)
    print('STS2 raw: ', sts2)
    print(f'{"PDoA":>10}{"STS1":>10}{"STS2":>10}{"STS1-STS2":>12}')

    # Here we print the actual value from the PDoA register and the PDoA calculated from the two STS PoAs
    for n, p in enumerate(pdoa):
        diff = (((convertPoA(sts1[n]) - convertPoA(sts2[n]))) + 180) % 360 - 180
        print(f'{convertPDoA(pdoa[n]):>10.3f}{convertPoA(sts1[n]):>10.3f}{convertPoA(sts2[n]):>10.3f}{diff:>12.3f}')

if __name__ == "__main__":
    main()