# Automated test AMP THD versus frequency

**URL:** <https://forum.quantasylum.com/t/automated-test-amp-thd-versus-frequency/2125>\
**Category:** Uncategorized\
**Created:** [December 11, 2025, 3:53pm UTC](https://forum.quantasylum.com/t/automated-test-amp-thd-versus-frequency/2125 "2025-12-11T15:53:47Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Gerrittube](https://avatars.discourse-cdn.com/v4/letter/g/3be4f8/32.png) [@Gerrittube](https://forum.quantasylum.com/u/Gerrittube)\
**Post date:** [December 11, 2025, 3:53pm UTC](https://forum.quantasylum.com/t/automated-test-amp-thd-versus-frequency/2125/1 "2025-12-11T15:53:47Z")

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With it’s default setting I get this error.

 ![IMG_2175](https://canada1.discourse-cdn.com/flex032/uploads/quantasylum/original/2X/6/64918281c624b55c2277db147e08decaa9c375dd.jpeg)

What’s happening here, what should I do?

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**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://forum.quantasylum.com/u/matt)\
**Post date:** [December 18, 2025, 12:42am UTC](https://forum.quantasylum.com/t/automated-test-amp-thd-versus-frequency/2125/2 "2025-12-18T00:42:18Z")

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There could be several things happening. A very common problem is the input overloaded while running the test. it’s harmless, but when overloaded, the data can’t be relied upon. In the error cited, you’ll see `Illegal Values Passed to FindPeakBin`

That can come from no data (due to overload) or you have specified start freq is \> stop freq. Since it’s not possible for the latter condition to occur at this stage, I’d guess input overload was the culprit. Remember to use sweeps, you first want to ensure you can manually make the measurements. That is, if you are wanting to look at THD from -50 to 0 dBV in a sweep, first make sure the measurement can be made manually at -50 and also 0 dBV.

Can you please post the setup options you used for the test?

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**Author:** ![Gerrittube](https://avatars.discourse-cdn.com/v4/letter/g/3be4f8/32.png) [@Gerrittube](https://forum.quantasylum.com/u/Gerrittube)\
**Post date:** [December 18, 2025, 9:09pm UTC](https://forum.quantasylum.com/t/automated-test-amp-thd-versus-frequency/2125/3 "2025-12-18T21:09:44Z")

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I didn’t specify anything, I try to run it with the default settings. I will check again!

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**Author:** ![Amanda\_Casper](https://yyz2.discourse-cdn.com/flex032/user_avatar/forum.quantasylum.com/amanda_casper/32/4054_2.png) [@Amanda\_Casper](https://forum.quantasylum.com/u/Amanda_Casper)\
**Post date:** [January 30, 2026, 12:38pm UTC](https://forum.quantasylum.com/t/automated-test-amp-thd-versus-frequency/2125/4 "2026-01-30T12:38:48Z")

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I’ve been struggling to get my automated sweeps looking this clean, so seeing your settings for the FFT and windowing is a huge help.