[AMPS] two tone test

[Ian White, G3SEK]

W8JI wrote:
>
>I wonder what Ian or W6FR think about your question, since they are 
>very experienced with IMD measurements.
>
My own measurement facilities are very limited, but I have analysed a
lot of data collected by other people.

If you extend the IMD plot out to very low levels, then the results from
a two-tone audio test can become very confusing because of carrier
leakage and IMD in the balanced modulator as well as the output stage of
the exciter.

For amplifier testing, the two-transmitter method is better... or maybe
a two-oscillator source feeding an ultra-linear driver? I rather like
the idea of Eimac's two-tone source described in 'Care and Feeding',
where the "driver" is a 4CX5000.


73 from Ian G3SEK          Editor, 'The VHF/UHF DX Book'
                          'In Practice' columnist for RadCom (RSGB)

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