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How to check the SNR of a modulated signal in VisualAnalog?

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Product Number: AD9652-310


I want to check the SNR through VisualAnalog by applying a modulated signal to the AD9652 EVAL. 

As shown below, I tried to check the SNR by applying a modulated signal with 20MHz Bandwidth, and it showed approximately -13.8 dB.

I think this is the calculated value with the settings for the CW signal. So I guess that's not an exact value.

I wonder if I can change the number of Bins of "Fund" in "FFT Analysis Settings" to accurately measure the SNR for the modulated signal.

If so, how can I calculate the number of those bins? Or is there any other way I can get the SNR for the modulated signal via VisualAnalog?


[edited by: seung-gon at 10:31 AM (GMT -4) on 5 Oct 2022]
  • Hello,

    If you open up the FFT Analysis Settings the User-Defined tab so that you can create a template similar to what is shown below which measures the left and right ADJ Channel ACLR performance of the waveform.   Note the following:

    1) Frequency is set to the the center of the signal  in MHz(or band) that is being measured.  CH_PWR

    2)  Single-Sideband is set to 1/2 the integrated bandwidth of the signal to be measured in MHz.

    3) For adjacent channel measurements, the frequency is set to the lower and upper channel center frequency is the same single-sideband settings as desired channel.    LADJ_PWR, RADJ_PWR.

    4) The ratio, L_ACLR is set to CH_PWR/LADJ_PWR.  The same is true for R_ACLR.

    5) For a system that is limited by thermal noise, the ACLR measurement should be similar to the CNR performance of the modulated waveform.

  • PMH, 

    Thank you for the detailed explanation.

    Could you provide the expression for the power of "ACLR" in the FFT Analysis Settings you suggested?

    In general, I wonder if ACLR replaces SNR to measure the dynamic range when a modulated signal is input.