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Frequency above 20 kHz with Sigma Studio and AD1940?

Hello, i want to expirement with sound in the ultrasonic frequency range, deom about 15 kHz to 40 kHz.

Can Sigma Studio operate in this frequency range, and can i do filtering, ect in this frequency range.
I want to use the AD1940 on the evaluation board EVAL-AD1940MINIBZ-ND , can i use this for my tests?
Also, i am concerned about anti alizing filters on the evaluation board will cut off too low, is that a concern, and can i modify these filters if they are there?

If the above cannot be done, do you have any suggestions for evaluation solutions in this frequency range.

Thank you if you can help me

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  • Hello Martin,

    Some of the high-frequency issues you've seen described here on EZ refer to older versions of SigmaStudio.  Many of these have since been fixed.  For example, now the Stimulus-Probe filter response tool works when set up properly for higher sample rates.  You can try it out without evaluation hardware:

         Select New Project, draw the ADAU1701 and USBi blocks into the window and connect them together:

         Set your sample rate to 96K or 192K as described in the link in my previous post -- make both HW and SW settings.  Ignore any USB error messages since you have no eval hardware connected.

         Drag the Simulation Stimulus and Simulation Probe Blocks into your Schematic Window.  Drag in your filter(s), placing them in between.  Add a DC source at the input just to keep things happy.  Press the Set System Sample Rate and Propagate Sampling Rate buttons on either side of the Sample Rate window, to make sure your sample rate choice was registered.

         Finally, open the Probe window and set the frequency and amplitude ranges as desired.  Press the Stimulus button to plot your filters' response curve:

         For examples of successful ADAU1701 signal processing above the audio range, see:

    Filtering strength 

    A -1701 FM MPX Demodulator 

         Best regards,

         Bob

Reply
  • Hello Martin,

    Some of the high-frequency issues you've seen described here on EZ refer to older versions of SigmaStudio.  Many of these have since been fixed.  For example, now the Stimulus-Probe filter response tool works when set up properly for higher sample rates.  You can try it out without evaluation hardware:

         Select New Project, draw the ADAU1701 and USBi blocks into the window and connect them together:

         Set your sample rate to 96K or 192K as described in the link in my previous post -- make both HW and SW settings.  Ignore any USB error messages since you have no eval hardware connected.

         Drag the Simulation Stimulus and Simulation Probe Blocks into your Schematic Window.  Drag in your filter(s), placing them in between.  Add a DC source at the input just to keep things happy.  Press the Set System Sample Rate and Propagate Sampling Rate buttons on either side of the Sample Rate window, to make sure your sample rate choice was registered.

         Finally, open the Probe window and set the frequency and amplitude ranges as desired.  Press the Stimulus button to plot your filters' response curve:

         For examples of successful ADAU1701 signal processing above the audio range, see:

    Filtering strength 

    A -1701 FM MPX Demodulator 

         Best regards,

         Bob

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