Measuring IMD with a 2204A

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natandmark
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Joined: Sun Oct 15, 2017 3:40 pm

Measuring IMD with a 2204A

Post by natandmark » Sun Oct 15, 2017 3:47 pm

Can someone explain how the PicoScope measures IMD? I'm used to a setup where you'd introduce two frequencies, say 1000 and 60 Hz, and then measure intermodulation signals at 1060 Hz etc. What is the PicoScope doing to measure IMD and what is it using as a reference for calculating percent or dB?

Gerry
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Re: Measuring IMD with a 2204A

Post by Gerry » Wed Oct 18, 2017 5:09 pm

Hi natandmark,

That is exactly what we do.

There is an explanation on how we calculate IMD on page 185 of our User Guide here: https://www.picotech.com/download/manua ... -guide.pdf. For the measurement we look for the 2 highest peaks as F1 and F2 (you can specify over what width a peak will be detected) and calculate IMD using the second order components.

Although the User Guide example shows a decibel calculation (which would be dBc) we provide the value as a percentage (which is just replacing '20logbase10' by 'x 100').

Regards,

Gerry
Gerry
Technical Specialist

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