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OPT9221: Base & De-aliasing Sin and Cos coefficients

Prodigy 50 points

Replies: 3

Views: 51

Part Number: OPT9221

Hi,

I'm back on our TOF project after a hiatus of a year or so and am currently at a point where I need to understand the details of the register to properly configure the OPT9221. We have our own circuit design interfacing the OPT9221.

The question at this time is on the Sin and Cos coefficients for the Base and De-aliasing. The datasheet provides 2 formulas (Equation 19, page 32) to calculate these Sin and Cos coefficients. However the results don't match the default values.

Formulas :

Base Frequency 4 quads 6 quads
Sin F1 Q0 Coeff 0 0
Sin F1 Q1 Coeff 32767 28377
Sin F1 Q2 Coeff 0 28377
Sin F1 Q3 Coeff -32767 0
Sin F1 Q4 Coeff 0 -28377
Sin F1 Q5 Coeff 32767 -28377
Cos F1 Q0 Coeff 32767 32767
Cos F1 Q1 Coeff 0 16384
Cos F1 Q2 Coeff -32767 -16384
Cos F1 Q3 Coeff 0 -32767
Cos F1 Q4 Coeff 32767 -16384
Cos F1 Q5 Coeff 0 16384
De-aliasing Frequency 4 quads 6 quads
Sin F2 Q0 Coeff 0 0
Sin F2 Q1 Coeff 32767 28377
Sin F2 Q2 Coeff 0 28377
Sin F2 Q3 Coeff -32767 0
Sin F2 Q4 Coeff 0 -28377
Sin F2 Q5 Coeff 32767 -28377
Cos F2 Q0 Coeff 32767 32767
Cos F2 Q1 Coeff 0 16384
Cos F2 Q2 Coeff -32767 -16384
Cos F2 Q3 Coeff 0 -32767
Cos F2 Q4 Coeff 32767 -16384
Cos F2 Q5 Coeff 0

16384

Default values:

Base Frequency 4 quads 6 quads
Sin F1 Q0 Coeff 0 0
Sin F1 Q1 Coeff 32767 28377
Sin F1 Q2 Coeff 0 -28377
Sin F1 Q3 Coeff -32767 0
Sin F1 Q4 Coeff 0 28377
Sin F1 Q5 Coeff 0 -28377
Cos F1 Q0 Coeff 32767 32767
Cos F1 Q1 Coeff 0 16384
Cos F1 Q2 Coeff -32767 16384
Cos F1 Q3 Coeff 0 32767
Cos F1 Q4 Coeff 0 16384
Cos F1 Q5 Coeff 0 16384
De-aliasing Frequency 4 quads 6 quads
Sin F2 Q0 Coeff 0 0
Sin F2 Q1 Coeff 32767 28377
Sin F2 Q2 Coeff 0 -28377
Sin F2 Q3 Coeff -32767 0
Sin F2 Q4 Coeff 0 28377
Sin F2 Q5 Coeff 0 -28377
Cos F2 Q0 Coeff 32767 32767
Cos F2 Q1 Coeff 0 16384
Cos F2 Q2 Coeff -32767 16384
Cos F2 Q3 Coeff 0 32767
Cos F2 Q4 Coeff 0 16384
Cos F2 Q5 Coeff 0 16384

I'm guessing in the case of 4 Quads that coefficient Q4 and Q5 are not needed so they are left at 0. Could you confirm this?

Where I have concerns is with 6 Quads case. The signs don't match. What are the right values and if it's not the equation results, what's wrong them?

Thanks,

  • Hello Myke,

    Regarding the questions related to OPT9221, please send them to the email list ti-3dtof@list.ti.com along with a reference to this E2E post.

    Regards

    Praveen

    TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs.

  • In reply to Praveen Aroul:

    I have sent the issue to the email suggested 5 days ago and have not received any reply. Is there an alternate for getting answers to questions on this product? Is it still supported?

    Thanks,

  • In reply to Myke:

    Hello Myke,

    I am closing the post since the discussion has been taken offline and responded.

    Please reach out to the email support list for any further questions.

    Regards

    Praveen

    TI makes no warranties and assumes no liability for applications assistance or customer product design. You are fully responsible for all design decisions and engineering with regard to your products, including decisions relating to application of TI products. By providing technical information, TI does not intend to offer or provide engineering services or advice concerning your designs.

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