OPT3101: Super-HDR Mode at close range

Matt McFadden

Part Number: OPT3101

Hello Alex,

I'm working on getting our design well tuned and calibrated. It is being used in a drone and I believe the design is fairly solid as our illumination crosstalk numbers seem pretty good.

What I'm seeing is that the sensor is generally progressing through the Super-HDR state machine outlined in 7.3.12.2 of sbas883a as expected. However when the device is very close to a target (about 1cm) the amplitude codes start to decrease when I expected them to increase. This eventually causes the HDR state machine to transition to a higher current level, and report incorrect distance information.

I've observed that the OPT3101EVM has the same behavior (the state machine jumps to a higher current output when near a target), but the Latte graphing tool reports a distance of zero.

Can you help me understand what is going on? The behavior of the EVM would work great for our situation too.

Best regards,

Matt

over 5 years ago

0 Alex Bhandari-Young over 5 years ago

TI__Mastermind 25895 points

Hi Matt,

Good you hear from you! Is it okay if I get back to you on this by this coming Monday?

Best,

Alex

0 Matt McFadden over 5 years ago in reply to Alex Bhandari-Young

Prodigy 70 points

Hi Alex. Yes, get back to me as soon as you can!

Matt

0 Alex Bhandari-Young over 5 years ago in reply to Matt McFadden

TI__Mastermind 25895 points

Hi Matt,

I tested this on the EVM and I see what you describe regarding the amplitude. Regarding EVM behavior this is done by checking for the phase codes wrapping around. What you are seeing is the phase going negative and wrapping around from 0 to FFFF. You can find the EVM check in the Functions.py file line 120

self.phase[-dataSize[0]:][phase>self.phaseValidRange[1]]=0

where (line 32) valid range is self.phaseValidRange=np.array([0,64000])

In this approach we say that the distances near 15m are not expected unless there is wrap around as EVM max range is around 10m and so set the phase to 0.

Best,

Alex

0 Matt McFadden over 5 years ago in reply to Alex Bhandari-Young

Prodigy 70 points

Thanks Alex. I see it and that is helpful. I'm moving forward again.

Best regards,
Matt

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OPT3101: Super-HDR Mode at close range