OPT8241 Voxel Viewer ToF problem to setting cosine and sine coefficient

Gianluca Vicidomini

Intellectual 500 points

Other Parts Discussed in Thread: OPT8241, OPT9221

Hello.

I'm trying to understand how to set up the sine and cosine coefficients in voxel viewer.

I have the OPT8241 evaluation board and I found at pag 31 in OPT9221 two formula to set the 12 coefficients.

In my case I use quad_count_max = 6 and these are the parameters extracted by the formula previously cited:

cos_f1_q0_coeff	32767	cos_f2_q0_coeff	32767
cos_f1_q1_coeff	16383,43	cos_f2_q1_coeff	16383,43
cos_f1_q2_coeff	-16383,6	cos_f2_q2_coeff	-16383,6
cos_f1_q3_coeff	-32767	cos_f2_q3_coeff	-32767
cos_f1_q4_coeff	-16383,2	cos_f2_q4_coeff	-16383,2
cos_f1_q5_coeff	16383,85	cos_f2_q5_coeff	16383,85

sin_f1_q0_coeff	0	sin_f2_q0_coeff	0
sin_f1_q1_coeff	28377,09	sin_f2_q1_coeff	28377,09
sin_f1_q2_coeff	28376,97	sin_f2_q2_coeff	28376,97
sin_f1_q3_coeff	-0,24072	sin_f2_q3_coeff	-0,24072
sin_f1_q4_coeff	-28377,2	sin_f2_q4_coeff	-28377,2
sin_f1_q5_coeff	-28376,9	sin_f2_q5_coeff	-28376,9

These parameters are correct?

I'm trying to understand which step of the calibration is wrong.

Thanks

over 9 years ago

0 Anand Gadiyar over 9 years ago

TI__Genius 15005 points

Gianluca,

You do not normally need to program the sin and cos coefficients. They are correctly programmed by default for 4 quads without dealiasing and 6 quads with dealiasing.

- Anand

0 Anand Gadiyar over 9 years ago in reply to Anand Gadiyar

TI__Genius 15005 points

Gianluca,

If you want to program 6 quads without dealiasing, then you need to set ind_freq_data_en = 1, ind_freq_data_sel = 1, and change only the sin_f2_*_coeff and cos_f2_*_coeff. Your values for these are correct.

- Anand

0 Gianluca Vicidomini over 9 years ago in reply to Anand Gadiyar

Intellectual 500 points

Thank you for your answer.
I have this doubt because if I have two identique profile called A1 and A2 with 6 quad cnt max.
For the profile A1 do not program these coefficients and for the profile A2 I put the coefficients that I wrote in this post and the results are:

phase Freq1 Freq2 dealiased phase
A1 3251 643 1702
A2 3250 3555 1699

the dealiased phase is the same why?

Maybe you can help me for the main problem, I'm trying to do a calibration with different frequencies than the standard profiles, in my case F1 = 30 MHz and F2 = 50 MHz, can you help? This is the link to the topic: e2e.ti.com/.../547334

0 Anand Gadiyar over 9 years ago in reply to Gianluca Vicidomini

TI__Genius 15005 points

If dealiasing is enabled, you should not be changing the sin/cos coefficients.

In your case above, the dealiased phase is the same because the frequency1 phase dominates the measurement and frequency 2 data is deemed unnecessary.

0 Gianluca Vicidomini over 9 years ago in reply to Anand Gadiyar

Intellectual 500 points

Thank you

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OPT8241 Voxel Viewer ToF problem to setting cosine and sine coefficient