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DLPLCR6500EVM: Spike-shape noise in the time domain

user5339974
Prodigy 20 points

Part Number: DLPLCR6500EVM

Hi,

I am using the 6500EVM in a sinple-pixel imaging application. In my experiment, illumination lights are irradiated to the DMD and all the lights reflected on the "on-state" micromirrors are collected with lenses and detected with a fast single-pixel detector. The 6500EVM is operated in "Pattern on-the-fly" mode with 400 images. I found spike-shape noises every 105 μs in the time domain like the image below, even though I set the exposure time of the 6500EVM to much larger time period like 3000μs. I would like to avoid that noises because they will strongly distort outputs in our experiment. What is the possible cause of it, and is there any way to avoid those 105μs noises when the exposure time is set at larger time period than 105 μs?

I have seen similar periodic noises when I used a DLP rightcrafter in the "static image" mode, but they disappeared when it is operated in the "internal stored pattern sequence" mode. therefore, I hope there is a way for the 6500EVM as with the DLP rightcrafter.

In addition to it, I would like to synchronize the 6500EVM with external trigger generated with a functional generator. If there is a solution to the problem, is it compatible with controlling DMD with external triggers? 

Thanks.

(The intensity is recorded with a AC mode detector)

  • 0
    TI__Intellectual 1080 points

    Hi,

    Welcome to the TI E2E forum :)

    Could you please confirm that you are able to get the noises with TI provided EVM and TI released firmware. If yes, which version?

    Also, it would be helpful to know if you are able to get similar noises with internal stored patterns in DLP6500 EVM.

    Regarding the 105us noises, the reason might be due to the fact that the sequences of patterns with higher exposure times are stitched together from the basic sequence of 105us width to generate the required time.

    Also, Could you please tell me the DLP lightcrater platform where you were not able to reproduce the noise

    Thanks

    Sachin 

  • 0 in reply to Bhatta
    Prodigy 20 points

    Dear Mr. Sachin

    Yes, I am using TI provided EVM(ver.4.0.1) and TI released firmware(ver.4.1.0).

    Also, the platform of my DLP lightcrater that works without noises is TI provided DLP® LightCrafter™ Evaluation Module with a DLP3000, TI released software(5.0.0), DM365(5.0), FPGA(2.6.43), and MSP430(3.0).

    I tried the internal stored pattern mode after your recommendation, but the same noise appeared.  

    Thanks.

  • 0 in reply to user5339974
    TI__Intellectual 1080 points

    Hi Akira,

    This is a known behavior and is addressed here

    This is documented but not released yet. I will discuss with my team regarding this and get back to you.

    Thanks for your patience!

    Regards

    Sachin

  • 0 in reply to Bhatta
    TI__Mastermind 43125 points

    Hello Akira,

    The article referenced on the last post of the thread mentioned by Sachin, is availableon line if you search for arxiv:1611.03397.  However, it is at your own risk and is not sanctioned by TI.

    It is a hardware solution and not a TI firmware solution.

    Fizix