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ADC12DJ3200EVM: ADC12DJ3200EVM

eli
Guru 13485 points
Part Number: ADC12DJ3200EVM
Other Parts Discussed in Thread: TSW14J57EVM,

Customer got the ADC12DJ3200EVM +TSW14J57EVM  and have below issue:

I am testing the ADC EVB, and I have some issues with the performance that I see.

The input is a two tone signal 1.7G and 2.3G samples at 6G.

I see around 14dB difference in the tones power at the output of the ADC (the tones are similar and tested in Spectrum analyzer)

Maybe I am not configuring the ADC or the FFT correctly?

  • 0
    TI__Genius 12965 points

    Hi Eli,

    Can you send a screen shot of the HSDC Pro result?  Also if you could save the data as csv file (HSDC Pro under File, Save as CSV) and send that we can also have a look at it.

    Have you tried other frequencies TO see if this is only happening around Fs/4?

    Ken.

  • 0 in reply to Ken C
    Guru 13485 points

    ADS12DJ3200.docxHello Ken

    Thanks.

    Please see the attached file, Now I have 3-2 dB difference between tones (I probably did better calibration), regardless of the center frequency (I changed either the sampling freq and the tones frequencies).

    I have a question regarding the interleaved spur, can it be avoided? How?

    Also, there is an option in the calibration to choose which FG ADC to calibrate , what is the importance of it?

    Should I change manually the gain and offset (on the right side of the calibration page) ?

  • 0 in reply to eli
    TI__Genius 12965 points

    Eli,

    I won't be able to address the specific device issues.  We may have to wait a few days until the apps engineer in charge of this device can respond.

    For the tone amplitudes, do they vary from capture to capture or are they fairly static?  Have you tried using single tones to verify the expected amplitude response of the input path?

    I will try to have a look at this ADC EVM in the lab as well.

    Ken.

  • 0 in reply to Ken C
    Guru 13485 points
    Ken
    The tones don’t vary between captures.
    I did one tone test, first at 1.7G and after at 2.3G, the difference was about 0.4dB.
  • 0 in reply to eli
    Guru 13485 points

    Hello

    Any news/update?

    B.Regards

    Eli

  • 0 in reply to eli
    TI__Genius 12965 points
    Eli,

    We put together a setup in the lab and should be able to have a look at this on hardware later today.

    Ken.
  • 0 in reply to eli
    TI__Genius 9675 points

    Hi Eli,

    We replicated your two tone test and measured the input signal within HSDC Pro and verified it using a Spectrum Analyzer. Both input signals show to have less than 1 dB difference as shown below.

    Please verify input signal.

    Regards,

    Jalen

  • 0 in reply to Jalen Tate89
    Guru 13485 points

    Hello Jalen

    Wlll it be possible to get write down the step by step setup configuration, here custome have 3 dB, so it could be  their  EVB performance or, and more likely, some incorrect configuration.

    B.Regards

    Eli

  • 0 in reply to eli
    Guru 13485 points

    Hi

    Please do your best for ASAP reply

  • 0 in reply to eli
    Guru 13485 points

    Maybe we should have a webex?

  • 0 in reply to eli
    TI__Genius 9675 points
    Eli,

    A possible reason for the 3 dB could be the combiner or splitter that you are using. Are you filtering both signals before combining them? You may want to verify the output of the combined signals with a spectrum analyzer to see if that is where the 3 db issue comes from.

    Also, what revision of board are you using?

    Jalen
  • 0 in reply to Jalen Tate89
    Guru 13485 points

    Hi

    See below feedback I got:

    I don’t filter the signals , these signals are the output of signal generators, so they are clean. I just combine them together.

    Of course I measured the two tune output with a spectrum analyzer and verify that they are almost the same.

    Below is picture of the EVM.

    Can we get step by step configuration requirements for the EVM?

  • 0 in reply to eli
    TI__Mastermind 43870 points

    Hi eli

    Even good quality signal generators (with very few exceptions) will have significant output power at harmonics of the fundamental frequency being generated. For this reason it is necessary to have a bandpass or lowpass filter in the path between signal generator outputs and ADC EVM analog signal input.

    All of our lab measurements utilize either bandpass or lowpass filters when performing normal dynamic performance, IMD3 and similar measurements.

    Please repeat your tests with an appropriate filter in the signal path. See Section 2.2 and Figure 3-1 of the ADC12DJ3200EVM User Guide for details on the type of filter to use, and how the input signal should be connected.

    Best regards,

    Jim B