I would agree with Fred.
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Despite what many articles and videos on the internet may suggest, including many professional ones, it is not easy to make practical and repeatable IMD measurements, especially at the IMD levels we are interested in.
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I've struggled with this, and have my own built band pass and notch filters and crystal oscillator based test sources. But even things like dirty connectors, especially things like BNC test leads, can cause results to vary considerably.
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The first step is to check that your IMD test rig is capable of producing results that are at least 10dB better than the device you are testing. Even this isn't really good enough, but it's something to aim for. Then try measuring known devices, such as the Mini-Circuits PGA-103+ or GALI-74+.
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I've always found these perform pretty closely to their published specification, and I tend to use one as a sanity check, before I try measuring something else.
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Regards,
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Martin
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On Mon, Oct 7, 2024 at 04:19 PM, Fred M wrote:
the Signal generators Output Stages and even the Splitter with its Ferrite nonlinearity are also a source of Intermodulation which limit your measurement dynamics. Again, IP measurement of high IPs is demanding, dont't fall in your own traps.
