[AMPS] IMD

[Peter Chadwick]

Quite a good test is to use wide band noise, too. A notch in the frequency
response of the noise allows the IMD to be measured under relatively realistic
conditions. This technique used to be used on analogue FDM systems, and has been
written up for SSB testing. OIt's one of the methods  in ITU-R Recommendation
SM328-9.

A plot of IMD against tone separation on a 2 tone test can be illuminating,
especially when you get below 50Hz tone spacing. Repeated with output power in
3dB steps as a parameter.

However, the answers may be such as you'd rather not know.....


73

Peter G3RZP


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