On Thu, 23 Apr 2009 11:27:37 -0400, Phil Hobbs
wrote:

John Larkin wrote:
On Mon, 20 Apr 2009 09:50:05 -0700 (PDT), Tim Shoppa
wrote:

A terminology question I suppose about the derivation of the term
"Superheterodyne" more than anything else:

Does the "Super" actually mean anything? Is there a Subheterodyne?

Traditionally superhets mix a higher radio frequency down to a lower
IF frequency, but certainly in the past few decades radios with IF's
above the RF frequency have become very common in broadband
applications, and those are still called superhets, not subhets :-).

Google turns up a couple hits on subheterodyne but other than one that
might mean "IF higher in frequency than RF" I don't recognize what
they mean..

I suspect that "Super" was more a marketing term than anything
else :-).

Tim N3QE

Supersonic.

http://en.wikipedia.org/wiki/Superheterodyne_receiver


John


Not a bad article, except that he seems to think that cascading multiple
stages at a single IF improves image rejection, and that very high IFs
are much less common than double conversion. (Does *anyone* use double
conversion anymore? Spur city.)

I did a double-conversion superhet FSK receiver for Reuters, umm,
maybe 20 years ago. I used state-of-the-art MF10 filter chips. Just
after I did it, they dumped all their wireline FSK newsfeeeds for the
Internet. Pity, it was a neat design.

We may do it again soon, for a scientific instrument, more digital
this time.

John