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AFE7950EVM: About HSDC Pro parameter change

Kazuto Odajima
Prodigy 80 points
Part Number: AFE7950EVM

After completing the setup according to the AFE7950EVM & TSW14J57 Bringup guide, and setting NCO: 9.5GHz,

Input Freq: 9.52GHz in step 8, a peak appeared at 20MHz as shown in the figure.

After that, when I set NCO:9GHz and Input Freq:9.02GHz, there was no peak at 20MHz.

I think the peak appears at Input Freq - NCO, am I wrong?

Or is it necessary to change the parameters on the Latte side as well?

Also, if I want to change the sampling rate, do I need to do anything with the Latte?

I change the sampling rate while keeping the input signal as it is, the signal will not be visible.

  • 0
    TI__Genius 11980 points

    Hi Kazuto,

    If only the NCO value is changed there there should be no need to change any HSDC Pro parameters. The peak should appear at Input Freq - NCO like you mention. One thing to check is how you updated the NCO frequency. Did you update the Rx NCO parameter in Latte or did you use the update NCO parameter (Also check which channel you updated). 

    The sampling rate can be updated in Latte, but one thing to note is that if you are using a sampling rate that is not a factor of 61.44MHz then you must use either an external LMK clock or an external AFE clock. 

    If you share the updated script that you are testing we can take a look at it. 

    Regards,

    David Chaparro

  • 0 in reply to David Chaparro
    Prodigy 80 points

    Hi David,

    I changed the NCO and sampling rate only in HSDC Pro, is that wrong?

    Is the parameters basically changed with the latte?

    Regards,

    Kazuto Odajima.

  • 0 in reply to Kazuto Odajima
    TI__Genius 11980 points

    Hi Kazuto,

    HSDC Pro is only for configuration of the FPGA and to create/capture tones. To change settings related to the AFE79xxEVM Latte must be used. 

    Regards,

    David Chaparro

  • 0 in reply to David Chaparro
    Prodigy 80 points

    Hi David.

    Understood. Thank you.

    What command should I enter in Latte to change the sampling rate?

    Or how can I modify an existing script?

    Regards,

    Kazuto Odajima.

  • 0 in reply to Kazuto Odajima
    TI__Genius 11980 points

    Hi Kazuto,

    The sampling rates can be modified using the parameters shown below. Please see the Configuration Guide and Latte User Guide for more information (These are available in the AFE79xx secure folder).

    Regards,

    David Chaparro

  • 0 in reply to David Chaparro
    Prodigy 80 points

    Hi David,

    Thank you for answering.

    I was able to change the sampling rate.

    Can RBW be changed in ADC Tab?

    Currently, it is grayed out at 7500Hz and the value cannot be changed.

    Regards,

    Kazuto Odajima.

  • 0 in reply to Kazuto Odajima
    TI__Genius 11980 points

    Hi Kazuto,

    The RBW is automatically calculated based on the ADC output data rate and the number of samples being captured. To update the RBW you can either change the ADC output data rate, must do the same in Latte, or you can change the number of samples being captured. 

    Regards,

    David Chaparro