>Hi Rich,
>As you know there's a lot of postings on "Amps" about IMD. Please tell us
>how to measure ( that's you ) IMD.
>Bob, w5pvr@gower.net
? The IMD produced by a human voice can not be approximated accurately
with a 2-tone test, so it must be measured with a human voice. Here's
how I measure it. With VFO-A and c. 40 db attenuation, note the S-meter
reading on the fundamental. Offset VFO-B 4.5kHz up for measuring LSB IMD
or 4.5kHz down for measuring USB IMD. Remove attenuation until the
S-meter is the same as on the fundamental. The change in db attenuation
is the total IMD of the signal. An alternative method is to make a graph
of S-meter indications vs, db using a step attenuator, switch between
VFOs A & B, note the S-meter indications, and subtract.
have fun
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
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