>> Easy enough to do when the filter is included within the system when
>> "calibrating" the receiver or spectrum analyzer with the known-clean
>> signal. This is, in fact, the ONLY correct method of "calibrating"
>> equipment: include all adapters, modules, etc. that will be in-line
during
>> the actual testing/measurement.
Of course. I assume by "known clean" you really mean "well characterized".
My lab, though well enough equipped for my purposes, does not have any NIST
certificates lying around.
Clean is probably a relative term and for the purposes of amateur
amplifier discussion can be less clean then other applications.
That pesky language thing again.
>> breakthrough occurred with the introduction, by NEC, of a line of four
>> GaAsFET broadband hybrid modules which exhibited slightly better
odd-order
>> IMD generation compared to industry-standard bipolar hybrids.
A breakthrough in this application (CATV?) domain. The introduction of the
HV MOSFETS with
decent characteristics at RF is another breakthrough which influences what
might be
of some interest to the production of power in the amateur HF bands.
One wonders where it might all lead. I read a paper on class-e power
production that
was presented at an AM broadcast engineer's convention 2? years ago. The
presenter was
very enthusiastic about the monetary and environmental economics of the
topology and
of the relatively cheap parts it could be accomplished with at their
frequencies.
FETs do seem to be pushing bipolars out of some of the last remaining areas
of relative
dominance in RF.
George K. Watson
K0IW
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