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Old 24th Oct 2021, 12:23 am   #21
Radio1950
Hexode
 
Join Date: Apr 2017
Location: Buderim, Queensland, Australia.
Posts: 428
Default Re: AD8307 probe-How is it used?

Jeremy,

Thanks.
I read all that, hand on heart.
Very interesting.

I saw some of that third harmonic variation with a quick test setup here, but I cannot control the phase of my second sig gen.
You have the benefit of owning two special sig gens.
If I vary the frequency of my third harmonic by 10 Hz (not the same but a minimum avbl step), I get "accuracy wobbles" on my AD8307 Milliwattmeter.
My two sig gens are M2018 and M2022 within 2 Hz by GPSDO.

The reason for your result with IMD two tone test is that the signals are not exactly coherent?

rgds
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