User talk:Chetvorno

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I will reply to comments below on this page, in order to keep the dialog in one place

Crystal radio[edit]

I believe this is incorrect: "A semiconductor crystal (detector) which extracts the audio signal (modulation) from the radio frequency carrier wave."

The diode only rectifies the voltage. It does not extract the audio part.

If the frequency of the applied voltage to a diode is 100,000 hz , the passed frequency will be rectified but at the same frequency, 100,000 hz.

The extraction of the audio frequencies from the rectified carrier frequency takes place in the headphones, which are of an electro-mechanical nature and are made to respond to 10 - 10,000 hz. The 100,000 hz carrier frequency can drive the earphone but it can only respond at audio frequencies. They cannot respond at 100,000 hz.Zedshort (talk) 00:22, 22 August 2015 (UTC)

Or more likely at the bypass capacitor across the headphone terminals that passes the carrier to ground, or the capacitance between the conductors in the headphone cord. Regardless, it is the nonlinear action of the diode that produces the baseband (audio) component. The spectrum of the signal before rectification consists of a carrier with sidebands, no audio frequencies. The spectrum of the rectified signal has the audio component in it. It also has carrier frequencies, but since we can't hear them that is not important. The low-pass action of the headphone driver is not really necessary; if the headphones could reproduce 100,000 Hz we would still hear the audio. Putting it in simple terms for the general readers who will be reading this section: the diode does extract the audio from the radio signal. --ChetvornoTALK 01:35, 22 August 2015 (UTC)
I was referring to the design of crystal set that consists only of an antenna, coil, diode, and ground. There is nowhere in that part of the circuit that the audio signal is "extracted." That part of the circuit only tunes out other frequencies and lets pass the desired frequency (100 khz). The audio is implicit in the waveform of the carrier frequency, rectified or not. Tuning in of a particular frequency takes place in the combination of antenna, and coil (with its inherent capacitance) and nothing more. The diode only rectifies the carrier voltage (perhaps 100 khz). The "extraction" of the audio signal from the rectified carrier wave takes place in the headphones as their nature makes them incapable of responding at the carrier frequency but able to respond to only at 10-10,000 hz. The audio waveform is not reproduced as a voltage anywhere in the system. It is implied, but it does not exist. Zedshort (talk) 15:50, 22 August 2015 (UTC)
There are no audio frequencies in the circuit before the diode, only radio frequencies. The rectifying action of the diode is what generates the audio frequency components. It can be proved mathematically. And the audio component certainly does exist; the concept of separate frequency components making up a composite signal is essential to the understanding of crystal radios. A bypass capacitor across the headphone terminals shows the audio signal exists; it removes the carrier pulses, leaving the audio signal "reproduced as a voltage" in the headphone wires. And even if the carrier was not removed and the earphone was able to reproduce it, we cannot hear 100 kHz sounds so the radio would sound the same. The fact that it doesn't matter whether the carrier is removed by a bypass capacitor, by the headphone inductance, or not at all, shows that the carrier removal is not the important part of the process. It is essential for introductory readers to understand that it is the diode which demodulates the signal, "translating" the modulation from the sideband (radio) frequencies to the baseband (audio) frequencies. --ChetvornoTALK 17:39, 22 August 2015 (UTC)
Sorry, I'm still not sure we are on the same frequency on this. Please consider reading this: http://www.crystalradio.net/crystalplans/xximages/crystal_receivers_for_broadcast_reception.pdf
It is dated, but it is one of the best expositions on the subject from the early days of radio. BTW, about the capacitor across headphones. Is that a result of using a piezo type earpiece vs a old fashioned coil type? Zedshort (talk) 02:18, 23 August 2015 (UTC)
Well, I agree, it does look like a good explanation of crystal radios generally. I think it could be used as a source in the article. However, it was written for a less technological age, and the explanation of the detector has been simplified to the point where it is incorrect or incomplete. "In order that the received currents should traverse the telephone, it is necessary that they be 'rectified', or turned into a current that is proceeding in one direction only." This isn't true, the earphone does not require current "in one direction", and the explanation misses the point of the rectification.
Amplitude modulation detection.png
Did you read the box on how the diode works in the Diode section of the article? Although short it is a pretty good explanation. The graphs from the article are at right. Graph (A) shows the AM radio signal voltage from the coil applied to the diode. The rapid cycles are the carrier frequency, while the slow undulations of the height are the audio signal. If this voltage was applied directly to the earphone, no sound would be heard. Each cycle of the carrier would push the earphone's diaphragm back and forth. The frequency of the carrier pulses themselves is far too rapid for the earphone diaphragm to follow, but this is not the reason that no sound is produced. The reason is that the slow audio variations, which is what we want earphone to respond to, are on both sides of the wave. When the amplitude of the positive half of the wave (above the axis) increases, the amplitude of the negative half (below the axis) increases just as much. Therefore the two opposite pushes on the diaphragm each cycle cancel out, the average value of the wave is zero, and the audio variations cause no net motion of the diaphragm. In electronics you say that the waveform has no audio frequency component.
In order for the sound to be reproduced it is necessary for the diaphragm to move in one direction as the amplitude of the wave increases, and the opposite direction as the amplitude decreases. To do this the diode rectifies the wave (B), removing half of each carrier cycle. The rectified wave does not average zero, its average value varies with the audio, that is, it has an audio frequency component. If this is applied to the earphone the average force of the pulses on the diaphragm will vary with the slow audio undulations. The diaphragm can respond to these audio frequencies, and moves in and out, producing sound. But this was only possible because the audio frequency component was present in the voltage applied to the earphone, which is due to the diode. --ChetvornoTALK 07:14, 23 August 2015 (UTC)
Yes, we are on the same frequency. But one point please. The middle figure that sketches in the time varying voltage at the peaks of the carrier frequency does not exist anywhere in any part of the radio. That line is suggested by the minds-eye and does represent the audio waveform. It should have been sketched in as a dashed line (oops it is). My point is that if you should attach an analyzer to various points in the circuitry you would not find that "smoothed" wave form anywhere. The line represents what the electro-mechanical device, known as an earpiece, can reproduce given the very rapid pulses of uni-direction current to which it is subjected and its slow response. As I said, the earpiece is in effect acting as a second form of filter, the first being the inductance and capacitance of the circuitry. Thanks much. Zedshort (talk) 16:49, 23 August 2015 (UTC)
Sorry, didn't mean to bloviate. I do take your point that the rectified waveform (B) is not the same as the audio (C). You're right, if there is no bypass capacitor you would not find the plain audio waveform anywhere in the circuit. --ChetvornoTALK 20:20, 23 August 2015 (UTC)
I'm pretty sure that the audio wave form exists nowhere in any part of the circuitry regardless of the design, bridging capacitor or no. That is the point that I think should be made. The assumed waveform outlined by the peaks of the carrier frequency only exist in a pseudo form. That audio waveform exists as an output of the speakers as that is the response that they have to the pulsating, rectified carrier current/voltage.Zedshort (talk) 21:18, 23 August 2015 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── No, with the bypass capacitor the pulses of carrier current are bypassed to ground and the voltage across the capacitor applied to the earphone is the pure audio waveform outlined by the peaks (curve C). The capacitor acts as the filter instead of the earphone; that's it's only function. The pulses of current from the diode charge the capacitor up to the dotted line and the capacitor voltage follows the slow audio variations, "smoothing" the carrier variations out. --ChetvornoTALK 00:23, 24 August 2015 (UTC)

Here are some supporting sources that it is the diode that produces the audio, not the earphone:

The circuits they are talking about are active circuits not passive. I was trying to keep it very, very simple and to talk about the simplest of crystal radios that are completely passive. They have no local oscillators or amplification.

Zedshort (talk) 20:26, 24 August 2015 (UTC)

From that source: "The diode detector separates the carrier from the audio, and allows the voice or music to be heard." No it does not. The diode is nothing but a rectifier that trims off half the voltage and leaves a pulsing direct current. The use of the term detector is highly misleading and should have never been used as it is the RLC tuner that "detects", or allows to pass, the desired frequency and rejects all the other frequencies. Simply because a thousand other people have these misconceptions in their head and presents them online or even in printing does not make them correct.Zedshort (talk) 20:26, 24 August 2015 (UTC)
"...semiconductor diode had not been invented, so extracting the audible modulation signal from the transmission..." And again a misperception. The galena crystal contains a crystal that can rectify the AM frequency and nothing more. It does not extract anything.

Note none of these references give any role in demodulation to the earphone or speaker except translating the audio signal to sound; some don't even mention it. --ChetvornoTALK 00:23, 24 August 2015 (UTC)

Well, I could go on and on, but the point is that people are sloppy in their expressions and many have misconceptions of how the simplest of passive radios work. I apologize if I wasted your time. I may be completely wrong, but will come to understand this completely some time soon. At which time I will travel the amature radio league circuit and place bets with those "experts" as to how such a device works and clean them out IF I AM CORRECT. thanks for your time Zedshort (talk) 20:26, 24 August 2015 (UTC)
If you do, let me know; I'll put my money on your side. I wouldn't bet against someone with your persistence. By the way, I wanted to say I came across your work on the Entropy article a while ago. I won't say I understand it; I'll never get those thermodynamic variables, but it was a lot clearer to me after your rewrite. Thanks much. All the best. --ChetvornoTALK 17:59, 25 August 2015 (UTC)
I am actually considering investing in an analyzer and other such equipment so I can investigate this in a rational manner. I work very hard at improving the expression of ideas here on WP. Of course I am careful to not stray to far from my field of "expertise." I guess it is time to review the electronics that I supposedly learned thirty years ago. There is still much work to be done on WP technology articles. Zedshort (talk) 16:47, 26 August 2015 (UTC)

Electrocution[edit]

Some apologies, I didn't notice your edit[1] just before mine, please excuse the term "bogus". I saw the text, thought it was old material, wondered how I missed it, and reworked it. I have been working on related articles and ID'ed the "Fred Peterson" involved as Frederick Peterson, a neurologist who does not seem to have a connection with Edison but does have a continual connection with Columbia University, where Brown's dog demo's were done. Also several sources show the electric chairs invention and final design was by Southwick and company (Fell). The Edison/Brown roll was to finalize the "AC or DC?" question and how much voltage (they pushed AC... go figure ;)). There could be a real Peterson/Brown/Edison connection here, they were all a little too "buddy-buddy" but need a ref on that. Fountains of Bryn Mawr (talk) 16:14, 24 August 2015 (UTC)

No problem; considering the incompleteness of my information, it looks like "bogus" was a pretty good description. Was doing some "drive-by editing" and thought I'd add something about the contributions of Edison, so I just used the first source I came to: Death, Money, and the History of the Electric Chair, on about.com. Should have known better than to trust some unsourced web essay. If I had remembered that you had worked on this subject I probably would have asked you to take a look at it.
It looks like you pretty much dismiss the influence of Edison's anti-AC campaign on the adoption of electrocution in the U.S. If that is true, why is the U.S. virtually the only country in the world to have used electrocution for capital punishment? --ChetvornoTALK 17:12, 24 August 2015 (UTC)
The answers are pretty well laid out in the War of Currents article... oh wait... no it isn't, its all in my head!!!!
Simple answer to your 2nd to last question is that electrocution was under development for 7 years (1881-1888) and signed into law on June 4, 1888. The war of currents (Brown's shenanigans) began on June 5, 1888 (with his angry newspaper letter). So the adoption of electrocution was actually before the War of Currents.
Why did the US adopt the chair?.... that's a good one. I see some answers at Capital punishment in New York, and I saw further text on how New York was on the verge of abolishing capital punishment..... governor David B. Hill railroaded the electrocution bill through to end run the abolitionists but he did not think the legislature would stay with him for long.... he had to quickly get the chair up and running and prove it worked.
BTW feel free to leave notes on this, I am actually up to the "chair" part and was fixing Wikipedia from the "outside in". Needs more work. Fountains of Bryn Mawr (talk) 19:26, 24 August 2015 (UTC)
Yeah, now I remember I noticed the discrepancy in the dates, that NY made its decision before the war was underway. Americans seem to have quite a history of finding new ways to kill people (Colt revolver, Gatling gun, precision bombing, napalm, nuclear weapons, neutron bomb, drones,...), and we like to try them out.
I glanced at your draft article. That's massive. Looks a lot more comprehensive than the current one. When I get a chance in the next couple of days I'll read it through. --ChetvornoTALK 00:26, 28 August 2015 (UTC)

2015[edit]

Tireless Contributor Barnstar.gif The Tireless Contributor Barnstar
For your large contributions to knowledge of Tesla coils and all things that "resonate". Fountains of Bryn Mawr (talk) 14:12, 27 August 2015 (UTC)

Thank you very much! Although I have to admit that in my case the word "tireless" translates to "unemployed". --ChetvornoTALK 18:02, 27 August 2015 (UTC)

Digital signal definition in analog signal[edit]

Hi Chetvorno, I noticed you defined digital signals in analog signal. I've extended and hopefully clarified your definition, and I would be interested in any comments you might have on that.

There's been some question about what a digital signal really is over at Talk:digital signal, and there's been a proposal to turn it into a disambiguation page. I thought you might be interested in the discussion.GliderMaven (talk) 07:49, 7 September 2015 (UTC)

Current wars[edit]

No longer in my head[2]. Fountains of Bryn Mawr (talk) 03:50, 8 September 2015 (UTC)

Project Diana[edit]

Hi Chet, My error in not signing in to edit the Project Diana page. The edits are factual.

The presence of the Ocean-Monmouth Amateur Radio Club on the Diana Site can be verified via both organizations websites [1] and [2]

The site is maintained by OMARC. OMARC was at that location before InfoAge was created under the supervision of the Department of Defense BRAC program. The arrangement was to mow lawns, paint buildings, pay for utilities, and be the custodians of the site.

You can verify location on Google, the IRS non-profit website, and the local phone directory.

Regards, Martin Flynn

N2mo (talk) 21:50, 14 September 2015 (UTC)

References

  1. ^ www.infoage.org
  2. ^ www.n2mo.org

Not totally[edit]

You checked in this note in Sentinel "The term "Crazy Ivan" refers to a submarine maneuver and has nothing to do with missiles". That is not true, the term was used to describe rouge launches. I have added a ref to demonstrate this. Maury Markowitz (talk) 12:46, 16 September 2015 (UTC)

Okay. What I was mainly concerned about was, if military jargon is used, it needs to be explained. General readers aren't going to know what a "Crazy Ivan launch" is. --ChetvornoTALK 15:15, 16 September 2015 (UTC)
Agreed, using jargon there was my bad. Maury Markowitz (talk) 14:22, 17 September 2015 (UTC)

JSTOR cleanup drive[edit]

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November 2015[edit]

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TRF and Neutrodyne[edit]

According to WP's Neutrodyne article, it is a special type of TRF rather than a separate type of radio receiver. Glrx (talk) 02:14, 16 December 2015 (UTC)

Absolutely. I just thought the sentence looked a little funny as it was. --ChetvornoTALK 04:55, 16 December 2015 (UTC)


Proposed new contributions[edit]

You have made a lot of useful contributions here even if you deleted some of mine (no offense taken, they were poorly introduced). In the non-radiative near-field section, I have planned to add soon some brief considerations concerning coupling coefficients and also to explain simply how resonance associated to large Q-factors improves the performances without modifying the link itself (the coupling coefficient depends only on geometric consideration or equivalently on self and mutal inductance or capacitance). I also think that the resonant induction could be introduced in a simpler manner (two distant coils in series with two capacitors), as it is used in most application (Witricity uses combined air transformers for impedance adaptation reasons nothing more). The same schematic is used in many recent papers for coupled capacitors (whatever the physical implementation). By the way the transverse capacitive configuration (not known as such) was introduced for power transfer by a New-Zealand guy a long time ago, but recent articles do not even mention him, can you help to restore his historical contribution. Finally they have been recently a few proposal based on radiative near-field techniques in the GHz frame (using for instance phase conjugation technique), they deserve according to me a section in the Wireless Power page. Besides, I am thinking on a Galinean Electromagnetism page that could be used for an elegant introduction of Quasi-Electrostatics and Quasi-Magnetostatics, your contributions will be appreciated.Henri BONDAR (talk)

Would it be okay if we moved this to the Talk:Wireless power page and I answered you there? That way we can keep the discussion together. Thanks. --ChetvornoTALK 14:36, 23 January 2016 (UTC)
Of course no problem. However, as I am quite new in the field :-)I don't know how to proceed for the transfer (copy/paste I assume).Henri BONDAR (talk)
Done ! Henri BONDAR (talk)

Elements[edit]

...[3] yes, but distributed models are also represented and analyzed by elements. SpinningSpark 18:01, 4 June 2016 (UTC)

Okay, I agree. "Many" should be changed back to "all". Thanks. --ChetvornoTALK 06:15, 5 June 2016 (UTC)

Reductio ad absurdum[edit]

Hi Chetvorno, I think it's good to add back "Society must have laws", but the first four references come from newspaper reporters and bloggers. For the purposes of a formal (or informal) application of logic, these sources are Wikipedia unreliable and should be removed. ~~ BlueMist (talk) 00:59, 16 June 2016 (UTC)

Hi. The references were not meant to establish that the given sentence is "valid", or that it is used in reliable sources, but just that it is widely used. Reductio ad absurdum is used in both scholarly debate and "informal" arguments such as blogs and newspaper letters, and whether the sentence has the form of a reductio is unrelated to whether it is a good argument. I added the references merely to give examples of the use of this particular reductio in public debate. Maybe I should have made that clear in the citations. --ChetvornoTALK 01:50, 16 June 2016 (UTC)
Reductio is only valid as a deductive argument! In the loose, real-world sense you are using it, it can be alleged to 'prove' any point of view whatsoever, including Machiavelli's or Stalin's societies. The reason is that the informal, empirical argument is always incomplete, or elliptical, and possibly, but not necessarily, unsound. In which case, anything goes.
However, I'm not arguing against this inclusion into the article, because this is indeed a common usage.
Only that according to WP:RS, the first 4 references are just not Wikipedia acceptable. ~~ BlueMist (talk) 02:53, 16 June 2016 (UTC)
Well, of course I agree that some reductios are more valid deductive arguments than others, and we want to use "valid" ones as examples. The problem in WP logic articles is that editors can argue endlessly about the validity of the content and meaning of an example like this, when the point of the example is to show the form of a reductio argument. You and I are agreed that this sentence is good enough to use as an example. The only reason I included the references was because in our recent Talk page argument with him, Rstrug demanded some; I was hoping to forestall another long argument with him. I agree the references are not very good; I'll remove the ones you object to. --ChetvornoTALK 16:48, 16 June 2016 (UTC)
Many thanks! I agree with the usage as stated. That one legit reference should be enough for support. ~~ BlueMist (talk) 17:55, 16 June 2016 (UTC)
I'll prove why reductio ad absurdum is dumb later on. You haven't refuted my argument, you've just ignored it. People adhere to the tenets of religion and none of them are laws. Rstrug (talk) 20:41, 16 June 2016 (UTC)
Oh well. So much for avoiding an argument. --ChetvornoTALK 23:00, 16 June 2016 (UTC)

Requested move[edit]

Hi, I followed up at WP:RMT. Any comments? — Andy W. (talk ·ctb) 00:41, 24 June 2016 (UTC)

Brought the request to RM here. Thanks. — Andy W. (talk ·ctb) 01:18, 24 June 2016 (UTC)
Looks fine to me, thanks. --ChetvornoTALK 01:33, 24 June 2016 (UTC)

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