[SOLVED] Passive Intermodulation Measurement

[jgraygoza]

Hello there.

I am currently in the process of putting together a PIM Test setup.
The plan is to get it as high as 40 dBm for the two tones.
The question I post here is the following:

I have an old 8340B signal generator.
I need to get another signal generator that's clean enough.
Also, I need to get a spectrum analyzer that has enough dynamic range for me to work with.
The Measurement I am looking for is -140 dBc or below this level for the measurement with an input power of +36 dBm for each tone.
The spectrum I have is an old 8593A which obviously will not cover the range.
Any suggestion will be greatly appreciated.

Also, if I am to input such power into the spectrum, I would attenuate it from +36 to -4 so I don't saturate the input.
The question here is how do I account for this difference when testing?

Thank you very much for the help.

Have a nice day.

 

[BradtheRad]

I don't know if a computer can produce distortion-less sine waves, but it might be worth a look. There are programs that will produce various frequencies.

There are programs that will record incoming audio and display how it looks on a frequency spectrum. I use Audacity, a free download.

I'm not sure it will give you 140 dB dynamic range, however.

Also, if I am to input such power into the spectrum, I would attenuate it from +36 to -4 so I don't saturate the input.
The question here is how do I account for this difference when testing?

Not sure if you're talking about the need for a reference signal...

Suppose you inject a tone of fixed amplitude every ten seconds? It will act as a reference for comparison to whatever test signals you are recording.

 

[jossion]

I would suggest to use a narrow band notch filter at the fundamental tone so that the high power which need not be seen in the spectrum analyzer can be removed and you can use the spectrum analyzer in the low dBm range.

 

[dcody]

Here are a couple different USB Signal Generators that you may want to look into. **broken link removed**