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OPT8241-CDK-EVM: Range Distance & Laser Diode

sslee
Prodigy 200 points

Part Number: OPT8241-CDK-EVM

Hi.

I am reading OPT8241 EVM's user Guide (Rev.B). document's number is "SBOU155B".

I have several questions. 

Q1. Question for understanding calibration profiles.

On page12, Table 6, I can see profile setting for Long Range, Short Range & High Ambient.

Because I am a novice about TOF yet, I just understand Unambiguous Range relys on modulation frequecny.

However on this table 6, Unambiguous range is related with several parameters.

Is there any formula to derieve 'unambiguous range' from other related parameters?

I hope to understand to calculate unambiguous range for each profiles. (long, short & abmient).

(I fully undetand real range is different with ideal value. )

Q2. On table 6, I can see Unambiguous range & Usable Range.

What is the factor to decide usable range? is it accuracy or????

  • 0
    TI__Expert 3975 points

    Hi, 

    Unambiguous range depends only on the modulation frequency. The relevant info regarding the unambiguous range can be found in the OPT9221 datasheet. See section 7.3.7.2:

    2) The usable range depends mostly on illumination power. You can get an idea of the range using the System Estimator software present here: 

  • 0 in reply to Suramya Gupta
    Prodigy 200 points

    Hi.

    Thank you for you help. 

    Please let me ask Question 1 AGAIN.

    1. ON OPT9221 Datasheet

    1) I understand the relationship between frequency & unambiguous range. 

      - Equation (20) on P31

     - Equation (21) on P31

    - Table 24 & Equation (27) on P33

    2) On SBOU155B document

    Please see Table 6 on P12.

    There are three kinds of Profiles, (Long, Short & High Ambient).

    Three profile's Base Frequency & De-aliasing Frequency are same. Base is 60Mhz, De-aliasing is 40Mhz.

    Each profile's unambiguous is as below.

    - 10M for long range,

    - 5M for short range

    - 5M for High Ambient.

    However if I follow Equation (21) of OPT9221 Datasheet, their unambiguous range should be all 7.5M.

    So last time, I guessed there are other factors to decide unambiguous range. 

    Could you check this again? 

    Thank you.

  • 0 in reply to sslee
    TI__Intellectual 2885 points
    Hello ,

    I will be closing this thread due to inactivity, if you have further questions feel free to ask a new question. Thanks
  • 0 in reply to Matt Mendez
    Prodigy 200 points

    Hello,

    I fully understand usable range is related with illumination power, I am studying using 3DOF estimator.

    Until now, I don't understand document SBOU155B's Table 6. Calibration profiles. I cannot calculate unambiguous range with frequencies.

    According to equation, Long Range profiles's abmiguous range is 7.5M, not 10M with freq1 60Mhz, freq2 40Mhz.

    That means unambiguous range has other factors, not only frequency.

    Could you arrange anyone who can help me?

  • 0 in reply to sslee
    TI__Intellectual 1660 points

    Hi sslee,

    Your understanding based on the OPT9221 datasheet is correct. Table 6 in SBOU155B document is incorrect. As you rightly pointed out unambiguous range of all profiles will be 7.5M. This will be corrected in the next update. Thanks for pointing this out.

    Thanks and regards

    Nithin

  • 0 in reply to Nithin Jose
    Prodigy 200 points

    Hello.

    Thank you for checking.

    I understand SBOU155B will be updated at next time.

    Could I get a revised table 6. Calibration Profiles before routine update?

    Are three profile's unambiguous are different or same, 7.5m?

    what I wanted to know are two points.

    one is soveled because you check. unambiguous range is 7.5m.

    I guess you mean it's for only long range profile.

    my second question was why 3 profile's unambiguous ranges are different even though their the frequencies are same.

    Thank you for your help in advance.

  • 0 in reply to sslee
    TI__Intellectual 1660 points

    Hi sslee,

    As I have pointed out in the previous reply, all the profiles have same unambigous range of 7.5m. The only correction in the table 6 will be this. The unambigous ranges ( currently 10m,5m,5m) will be replaced by 7.5m,7.5m and 7.5m.

    Regards

    Nithin 

  • 0 in reply to Nithin Jose
    Prodigy 200 points
    Hello. I got it. It's clear now. Thanks for your help.
    Everything about TOF is new to me.