On Tue, 04 Mar 2003 07:32:09 -0500 Zyg Skrobanski <af4mp@mindspring.com>
writes:
> >IMD (splatter) is not considered spurious emissions by ICOM. All
> that tells
> >you is harmonic suppression.
>
> Is the IMD normally measured by using a two-tone test? If so, does
> the
> particular frequency of the tones (within a normal audio 3KHz
> bandwidth)
> change the IMD, i.e. which two tones would give the worst case
> reading?
> --
> Zyg AF4MP
> Roswell GA USA
Hi Zyg,
Yes.
400 & 1800 Hz are used for the FCC (US) tests.
If moving those frequencies a little changed the IMD, I would suspect
the SSB generating stages rather than the amplifier.
A pair of CW signals run through a power combiner is a better source
for testing power amps than any amateur exciter. Even if an exciter has
reallllly good IMD it may add to the IMD of the amplifier under test in a
non-linear fashion making it hard to discern the true figures for the
amplifier being tested.
73 & Good morning,
Marv WC6W
*
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