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ADC12DJ3200EVM: High Noise Floor in FFT

jayamomo
Prodigy 60 points
Part Number: ADC12DJ3200EVM
Other Parts Discussed in Thread: ADC12DJ3200

Hi,

I am using the ADC12DJ3200EVM with the TSW14J57. I am following the instructions in the user guide SLAU701. I setup the ADC as detailed in 3.10.1 through 3.10.3. Then I go to step 3.11 and 3.12. I am supplying a filtered 1.91GHz signal at 0dBm to the VINA input (J2) of the ADC evaluation board. I see a raised noise floor. Can you please let me know what I may be doing wrong? Thanks. See images below:

With no input:

With 1.91GHz input

Thanks

Jay

  • 0
    TI__Mastermind 30100 points
    Hi Jay,

    I have contacted one of our applications engineers responsible for this part, and they will reply shortly.

    best regards,

    -Steve Wilson
  • 0 in reply to Steve-Wilson
    TI__Genius 12965 points

    Hi Jay,

    Can you try selecting Reset Board under the Instrument Options and then try a capture after that?

    Can you also post the ADC12DJ3200 GUI A screen shot?

    Ken.

  • 0 in reply to Steve-Wilson
    TI__Mastermind 20541 points

    Hi Jay,

    There are couple of things I want you to try.

    1. Don't apply any input signal to the ADC and do a capture and see if your noise floor is still raised.
    2. Program ADC12DJ3200 in JMODE2 or JMODE3.  These both are two channel modes. Setup HSDCpro for accordingly. Apply the input signal  to VINB and see if your noise floor is still raised on CHB.
    3. There is a texas insturments logo on top of evm next it should say which REV the board is. Can you please provide that info.

    Regards,

    Neeraj Gill

  • 0 in reply to Neeraj Gill
    Prodigy 60 points

    Hello Neeraj,

    1. I already have tried that. In JMODE0, you can see the FFT screenshot in my message above.

    2. I tried JMODE2. Below are the FFT images with NO SIGNAL

    Ch.A

    Ch. B

    It looks like something might be wrong with Channel B?

    3. The board rev says "ADC12DJ3200EVM REV E3"

    Thanks

    Umesh

  • 0 in reply to jayamomo
    TI__Mastermind 44560 points

    Hi Umesh

    The Rev E3 board is not 100% compatible with the standard TSW14J57 settings provided with High Speed Data Converter Pro. Those settings are intended for the production Rev A board.

    Due to some logistics problems prior to release of the ADC12DJ3200 and ADC12DJ3200EVM some of the Rev E3 boards managed to get into distributor inventory. These should be replaced with Rev A boards.

    If you obtained your board through a distributor I recommend you initiate a return and have them provide a replacement board, first confirming the new one they are sending is a Rev A.

    If you have a time crunch and need to get the current board working now I can create and provide an updated configuration file(s) to enable the JMODE(s) you are using. Will files to support JMODE0 and JMODE2 be sufficient for your current testing?

    Best regards,

    Jim B