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 :-).
My recollection is that Armstrong used the term "supersonic heterodyne" to note the fact that the beat frequency between the signal and LO was "supersonic."
I saw that in Wikipedia too. I didn't believe it, it doesn't make sense. Why not just call all radio frequencies and IF frequencies above 20kHz "supersonic"? Then all radios (*) are supersonic, and we're back to super meaning nothing at all.
(*) OK, I know about lowfers and there is submarine RF communication below 20kHz. If I listen in to that with a superhet is it then really a subhet?
Reminds me of a Simpsons episode where Bart and Homer are arguing about something, and Bart parrots what Wikipedia says on the subject. Homer says in a deep resentful voice "We'll fix THAT when we get home!"
Compared to the crystal recievers of the day, whose signal path was either RF or audible , "supersonic" may have been a useful descriptive term at the time.
So a "subsonic" heterodyne may be possible as a theoretical architecture, but its final output would be severely bandlimited by the subsonic IF. Steve
I saw that in Wikipedia too. I didn't believe it, it doesn't make sense. Why not just call all radio frequencies and IF frequencies above 20kHz "supersonic"? Then all radios (*) are supersonic, and we're back to super meaning nothing at all.
(*) OK, I know about lowfers and there is submarine RF communication below 20kHz. If I listen in to that with a superhet is it then really a subhet?
Reminds me of a Simpsons episode where Bart and Homer are arguing about something, and Bart parrots what Wikipedia says on the subject. Homer says in a deep resentful voice "We'll fix THAT when we get home!"
I didn't really trust Wikipedia on this (it uses unusual language to talk about perfectly conventional subjects) but I did find my December
1922 QST, and it says (page 11):
In December, 1919, Major E. H. Armstrong gave publicity to an indirect method of obtaining short-wave amplification, called the Super- Heterodyne. The idea is to reduce the incoming frequency which may be, say 1,500,000 cycles (200 meters), to some suitable super-audible frequency which can be amplified efficiently, then passing this current through a radio frequency amplifier and finally rectifying and carrying on to one or two stages of audio frequency amplification.
To me that sounds a little less awkward and more natural than the derivation that Wikipedia tries to draw.
** Refers to the term " supersonic frequency " - the general name for any frequency between the upper limit of the audible range ( 20kHz ) and the lower limit of common radio transmission frequencies or "long waves" at about 150kHz.
** No.
** The name now refers to any receiver that involves a frequency changer stage prior to detection.
If you want to know the meaning of any term, you have to study how PEOPLE used it - both in the past and the present.
Only complete fools and radio hams study the words themselves in isolation and try to de-construct them.
So, if a basketball player from a certain team in Seattle were flying on the Concorde, and listening to a particular brand of antique radio, it'd be a supersonic SuperSonic's Superdyne supersonic heterodyne?
The heterodyning of two signals was barely known around 1902 to
1904 when very early entrepreneur-experimenter Reginald Fessenden was fooling around in his lab trying to improve the sensitivity of early coherer-type detectors. Fessenden tried mixing the output of a very low-power spark transmitter with his simple receiver and reported getting a clearer tone from a distant station. Fessenden was keen on making himself known so he wrote that up and it was published.
However, by 1906 the first audion tube was made and in a few years later, some production units were available for experimenters, namely a very young Armstrong...who went on to start gaining fame with his regenerative tube receiver. By 1918, Amstrong was now a Major in the US Army and stationed in Paris with WW One having stopped. Armstrong remembered the Fessenden experiment and remembered the 'heterodyning' process of mixing low-level RF signals with higher-level RF (the 'Local Oscillator' as it became known), getting two extra mixing products out of a 'mixer' stage (sum and difference of the two main input frequencies). By now academics had gone into the heterodyning process in more detail with at least 14 years between Fessenden's experiment and Armstrong's tube version.
Armstrong's patent application promised an equal-selectivity at any antenna-input frequency, something not possible with TRF receivers, narrower at lower frequencies, wider at higher ones.
Might have been had there been ANY real "market" for radios back then. Of course, anything RF done with vacuum tubes beat the pants off any crystal detector and spark transmitter, so it was definitely a 'super' thing. :-)
Actually, Ed Armstrong had a battle with various nations on the patent for his superheterodyne, at least a year or two later with someone in England and another in France. Patent suits would continue to dog Armstrong until the end of his life, probably causing the depression that, in turn, caused him to suicide. Just the same, Armstrong had the chutzpah to promote his ideas and he is truly the father of FM broadcasting allowing high- fidelity music to any FM receiver. He was no slouch in getting organized and promoting himself.
There's a whole lot of material on Edwin Howard Armstrong at several websites, reachable through members of the Radio Club of America, the oldest association (since 1909) and still going.
--------------- The three basic forms of modulation of a carrier (amplitude, frequency, phase) were worked out by John Carson of AT&T in 1915, before Armstrong got going on his 'superhet' idea. Whether or not Ed saw those is unknown, but Carson had them worked out already. Those very early 'radio' experimenters, from academics to amateurs, were very very busy in the first two decades of 'radio' existance, going from essentially nothing to several somethings. 'Radio' stayed a fertile field for scientific-engineering innovation for three more decades, spurred into a couple quantum jumps during the World War II years.
Reginald Fessenden sort of faded into the woodwork after his famous "Christmas Eve" sound broadcast of 1906...using a spark transmitter whose antenna wire was modulated by a special carbon microphone! I doubt that any AM broadcast station ever tried to use that system since so it was an early curiosity in radio history. Armstrong's name spread and so did his inventions...not just the regen or superhet, but also the super-regenerative for high HF and into VHF (note the 'super' addition by the extra oscillation) and, of course, to FM broadcasting.
Everyone ought to realize that "Wikipedia" data can be written by ANYONE and that the ARRL (who has always published QST) is NOT a technical- expertise source. Ed Armstrong's original patent on the superheterodyne can be found on the 'web in digitized image form. Takes some searching.
The word prefix 'super' generally refers to something 'better' than the word without that prefix. Armstrong got a patent for the regenerative detector, He also got a patent for a SUPER-Regenerative detector.
Think also SUPERman. 'Mercado' has already been mentioned, but folks have neglected the MARKET...which expanded into SUPERmarket, generally a chain of them under one label or another.
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