[Amps] Re: FW: How are IMds created

[peter.chadwick at Zarlink.Com]

If the IMD products were the mixing of the harmonics, it should be possible
to trap them out.

Pappenfus et al point out the fallacy of regarding IMDs as being the mixing
of the harmonics: it is however, a somewhat theoretical point. Viewing the
products as mixing of harmonics  does give an easily understood  view of
what IMDs are, even though it's not quite correct.

Many years ago, I did a transmitter with a dual gate MOSFET balanced mixer.
A problem was a 3rd order mixer product of 2IF - LO falling in band, and
the insertion of low inductance high capacitance traps tuned to 2IF in the
source of each MOSFET produced a very useful reduction in the level of the
3rdorder  product - which strictly, shouldn't be expected from a pure
consideration of the transfer function.

73

Peter W6/G3RZP