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Original question:

Compiler/OPT9221: Writing calibration parameters in register OPT9221

Compiler/OPT9221: Calculating frequency calibration coefficients

Semen Semenov
Intellectual 647 points
Part Number: OPT9221
Other Parts Discussed in Thread: OPT8241

Tool/software: TI C/C++ Compiler

Hello TI,

We made our ToF board base on our OPT9221 and OPT8241 design.

I want to carry out frequency calibration in de-aliasing mode.

I set f1 and f2, calculate f_eff = GCD(f1, f2); measure by oscilloscope real f1 and f2 values - f1' and f2' in mode ( ind_freq_data_en = true; IND_FREQ_DATA_SEL = 0) and ( ind_freq_data_en = true; IND_FREQ_DATA_SEL = 1) respectively.

How do I need to adjust unambiguous range from R =  c/(2*f_eff)  to R' with real measured f1' and f2' values?

Is it R' = c/(2*f_eff'), where f_eff' = GCD(f1', f2')? (if yes,  R' will able change very strongly)

  • 0
    TI__Expert 3975 points

    Semenov, 

    Please use the base frequency for the frequency calibration in the de-aliased case. Note that this correction is done in software. 

    Suramya

  • 0 in reply to Suramya Gupta
    Intellectual 647 points
    Thank you for your answer!
    I.E. I set up de-aliased setting in OPT9221, calculate before-hand relation f1/f1' (f1 is base frequency, f1' - actual frequency), measure Phase data (which are corrected by common phase offset, temperature correction coefficients and non-linearity calibrations) and only after recalculate unambiguous range from R to R'.
    So, how to do it? ( R' = c/(2*f1') ? )
    Because without frequency calibration unambiguous range R = c/(2*f_eff) is sufficiently more than R' = c/(2*f1') .
    Or it is need to recalculate depth:
    d' = d/(f1'/f1) ?
  • 0 in reply to Semen Semenov
    TI__Expert 3975 points
    Semenov,

    The calculation of the unambiguous range remains the same. R = c/(2*f_eff). You just correct for the first frequency using frequency calibration in software.

    Suramya