If Superheterodyne, why not Subheterodyne?

You forgot to add, Phil, that my mother was a hamster and my father smelt of eldeberries.

Tim.

"Tim Shoppa = Autistic Troll "

The best Wikipedia articles are often filled with good checkable references, but other times it sounds like they were written in a foreign language and translated into English

** Only indicates an autistic lack of comprehension.

Just because a Wikipedia entry isn't well-written or sounds awkward

** You are autistically obsessed with imaginary flaws in the writing.

Most likely because you have gone quite insane.

Somewhere there's a bunch of people who spend their time correcting and improving Wikipedia entries, and I think overall they are doing a good job, but that doesn't mean the result is always devoted to my interests.

** What a revolting, pompous narcissistic pig you are - Tim.

Just like anything else in this world, it's got workers and it's got managers and they aren't always devoting their attention to the little corners of arcania that I live in.

** I was much too kind earlier ....

It's not that the Encyclopedia Britannica is perfect either. I can open it up to the very few subjects that I happen to be expert on and find over-simplifications and a lack of cites to what I consider to be the best references.

** Mere narcissism has just turned into full blown, autistic ego-mania.

Of course in academia I got real used to opening a journal and instead of reading the articles, to go straight to the references and see if they are quoting one of my articles :-).

** Shoppa's self delusions have made him a legend in his own mind.

When all he really has become is " history ".

..... Phil

Even when he was young?

--
John

If it comes to that, old Longwave/Mediumwave superhet receivers generated an IF for the LW band that was higher than the frequency of the incoming signal. The IF was usually a frequency between the two bands.

Sylvia.

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.)

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net

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

The IF frequency is above the signal frequency, hence the "super" prefix.

There are also "homodyne" receivers, where the local oscillator is at the same frequency as the received carrier. These convert the input signal all the way down to the output signal in one step. This was an early idea, but until phase locked loops were figured out, hard to make work. It's used today in some microwave and optical systems.

John Nagle

Subheterodyne?? BFO???

I thought it was a contraction of "supersonic heterodyne".

At that time receivers were TRF and in many cases used reaction (i.e. controlled positive feedback) to improve selectivity and gain. This could be exploited to receive CW signals by advancing to the point of feedback resulting in an audible heterodyne (whistle) at the output whwn tuned close to a signal.

The supersonic heterodyne performed in a similar way but was intentionally above audible range (i.e. supersonic) for amplification at the intermediate frequency.

kevin

"John Nagle the Flatulent Fool"

** Nagle just did another smelly fart.

Peeeeeeuuueeee

.... Phil

I think that the way to answer a question like this is to try to find written material which originated as close as possible in time to the introduction of the term in question. Wikki entries should give references to original material, but of course those are not always easy for everyone to find, and to study.

The best that I can do in the way of original references with the books on my shelves is to quote from the 'Admiralty Handbook of Wireless Telegraphy 1931', HMSO, London, 1932. On page 721 is written

- '... This use of amplification at a frequency intermediate between that of the incoming signal and an audible frequency gives this circuit its name of super-heterodyne, or supersonic heterodyne receiver'.

The discussion goes on to describe an Admiralty receiver having an IF frequency of 30kHz, which is just what you would expect a supersonic frequency to be. To my mind this settles the question. Andy G4OEP

A terminology question I suppose about the derivation of the term

I think that the way to answer a question like this is to try to find written material which originated as close as possible in time to the introduction of the term in question. Wikki entries should give references to original material, but of course those are not always easy for everyone to find, and to study.

** All one had to do was follow up on the "external links" at the end of the superhet Wiki

the very first one of which is:

Then go to footnote #11:

-----------------------------------------------------

" Armstrong, "A New System of Short Wave Amplification," Proc. I.R.E. 9 (Feb. 1921), pp. 3-27. QST 3 (Feb. 1920), pp.5-9, 13. This paper uses the term superaudible heterodyne, from which superheterodyne is derived. The British tended to use supersonic. Incidentally, the first use of the word superheterodyne that I have seen, is in QST for March 1921 (p.41) but evidently from the context it was in common use by then. "

------------------------------------------------------

Note the reference to " superaudible heterodyne " is from 1921 and Armstrong himself !!

Also it explains how the Poms ( Armstrong was an American) liked to use "supersonic" in relation to those frequencies above the audible range.

The best that I can do in the way of original references with the books on my shelves is to quote from the 'Admiralty Handbook of Wireless Telegraphy 1931', HMSO, London, 1932. On page 721 is written

- '... This use of amplification at a frequency intermediate between that of the incoming signal and an audible frequency gives this circuit its name of super-heterodyne, or supersonic heterodyne receiver'.

** Fine, but that book is ten years later and has no direct connection to Armstrong's invention.

The discussion goes on to describe an Admiralty receiver having an IF frequency of 30kHz, which is just what you would expect a supersonic frequency to be. To my mind this settles the question.

** The Q was settled by the first couple of replies Shoppa got here - but he simply had no interest in having one of his mad, pet theories proved wrong so easily.

Shoppa was trolling as usual and no simple facts were not gonna spoil his puerile mischief.

..... Phil

mikea wrote: [Philthy snipped]

Hi Mike, nice to see you here!

-- W . | ,. w , "Some people are alive only because \\|/ \\|/ it is illegal to kill them." Perna condita delenda est

---^----^---------------------------------------------------------------

are

Just the same, i try. perhaps my approach can be better described as having adequate coverage at adequate depth. Or sort of turning thinge sideways and trying to get best area with a very complex shape with many largish estensions in some areas and virtually none in other places. Knowledge is kind of fractal any way. .

that

=20

Double conversion may be thought to be passe an awful lot of sattelite TV receivers are double conversion or triple conversion. Think LNB. .

Subheterodyne?

lower

IF's

:-).

that

what

subheterodyne and it just might sail through :-)

supermercados in Spain.

we'll

That's it. You are now on the list of posters that are not safe to read with a mouthful. .

And the claim that a TRF receiver was simpler to use than a super?heterodyne. It makes you wonder if the author even knows how a TRF receiver works. Most had a separate knob per tuned circuit, since the attempts at gear driven tuners didn't track very well.

--
You can\'t have a sense of humor, if you have no sense!