AWRL6432: How to understand the value of compRangeBiasAndRxChanPhase

Shawn Li(Radar)

Part Number: AWRL6432

Tool/software:

Hi team,

I have one question on AWRL6432 about this command

compRangeBiasAndRxChanPhase 0.0 1.00000 0.00000 -1.00000 0.00000 1.00000 0.00000 -1.00000 0.00000 1.00000 0.00000 -1.00000 0.00000

In the userguide, this command is descripted like below:

The virtual antenna pattern of TI EVM and antennaGeo is like below:

If we choose BPM waveform, then the phase should be:

virtual antenna 1-3 are same as virtual antenna 4-6 or

virtual antenna 1-3 are opposite as virtual antenna 4-6.

But it seems the phase compensation of virtual antenna of 1, 3, 5 is set to 1, and virtual antenna 2, 4, 6 is set to -1.

Can you help me understand this?

Regards,

Shawn

over 1 year ago

0 zigang Yang over 1 year ago

TI__Mastermind 40335 points

Hi, Shawn:

Where did you get the conclusion that

If we choose BPM waveform, then the phase should be:

virtual antenna 1-3 are same as virtual antenna 4-6 or

virtual antenna 1-3 are opposite as virtual antenna 4-6.

Let us give an example between virtual antenna #1 (TX1-RX1) and visual antenna #4 (TX2-RX1). With BPM mode, between these two virtual antennas, you always have

chirp0: (TX1-RX1) + (TX2-RX1)

chirp1: (TX1-RX1) - (TX2-RX1)

you will need to have BPM demodulation to demodulate virtual ant #1 and #4

TX1-RX1 = (chirp0 + chirp1)/2;

TX2-RX1 = (chirp0 - chirp1)/2;

Since we know there is 180 degrees of phase offset between virtual ant #1 and #4, after BPM demodulation, we can now apply the phase compensation. Let me know if you see any problem with this procedure.

since

Best,

Zigang

0 Shawn Li(Radar) over 1 year ago in reply to zigang Yang

TI__Intellectual 875 points

Hi Zigang,

I understand your procedure.

The initial phase of

Chirp 0: TX1 0 deg, TX2 0 deg

Chirp 1: TX1 0 deg, TX2 180 deg

So,

TX1-RX1(virtual 1), TX1-RX2(virtual 2), TX1-RX3(virtual 3) are all equal to (Chirp1+Chirp0)->2*TX1 (phase: 0deg).

TX2-RX1(virtual 4), TX2-RX2(virtual 5), TX2-RX3(virtual 6) are all equal to (Chirp1-Chirp0)->2*TX2 (phase: 180deg).

Consider the command's format, it should be

compRangeBiasAndRxChanPhase 0 1 0 1 0 1 0 -1 0 -1 0 -1 0

Please help review the error in my understanding.

Regards,

Shawn

0 zigang Yang over 1 year ago in reply to Shawn Li(Radar)

TI__Mastermind 40335 points

HI, Shawn:

There is 180 degree phase difference between TX1 and TX2.

There is also 180 degree phase difference between RX1 and RX2, and 180 degree phase difference between RX2 and RX3. So the phase between the three RX are [1 -1 1].

So when you combine these two factors, the phase shifting among all the visual antenna becomes

[[1 -1 1], -1*[1 -1 1]] => [1 -1 1 -1 1 -1]

Best,

Zigang

0 Shawn Li(Radar) over 1 year ago in reply to zigang Yang

TI__Intellectual 875 points

Hi Zigang,

Understand. Thanks! And can you tell me the source of 180 degree phase difference in RX?

Regards,

Shawn

0 zigang Yang over 1 year ago in reply to Shawn Li(Radar)

TI__Mastermind 40335 points

Hi, Shawn:

You can refer to the following e2e thread:

https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1289288/awrl6432-phase-shift-of-lambda-between-awrl6432boost-rx-channels/4928166

Best,

Zigang

0 Shawn Li(Radar) over 1 year ago in reply to zigang Yang

TI__Intellectual 875 points

Hi Zigang,

Thanks for your reply.

Regards,

Shawn

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AWRL6432: How to understand the value of compRangeBiasAndRxChanPhase