Thanks. So arithmetic tells me that an electron is likely to be back to normal behaviour about 1.2nm after leaving the BQP. Within perhaps 10nm almost all electrons will have scattered off something so will be 'normal' again.bcarso said:
The mathematical connection between Heisenberg and Fourier is useful, but it does provide scope for the unscrupulous to drag "quantum" into things where it doesn't really belong, such as audio electronic circuits.
If even-order harmonics derive from even-order distortion (they need not, although usually they do) then the even-order distortion will create a DC term too. This disappears completely at the first coupling cap or transformer encountered by the signal. So DC does not necessarily imply even-order distortion; even-order distortion does not necessarily imply DC. Similarly for any asymmetric waveform: DC and asymmetry do not necessarily accompany each other. Having said that, I'm not sure why we are discussing such elementary issues.
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And the second review IIRC is mine. I swear I get no kickback
Lot of those pricing anomalies going on. Sometimes they are errors, sometimes the book is already gone and the listing not updated, but more frequently a bookseller just wants to clear some inventory. Notice closely the ones that show stock on bookfinder dot com (a great site that searches many sites) but then suggest they will ship in a few months! This can mean they will ship if they can find the book! Or, it is not disclosed but it may be a print-on-demand book. Note as well that sellers use multiple listing services and there may be six or seven occurrences of what is actually the same physical copy --- this can be detected from the identical description texts.
I ramble off topic and say this, as I am in the midst (on and off again for >7 years) of cataloging my books, and now getting more meticulous about noting condition and looking for true comparables for valuations. Things fluctuate a lot, with the advent of one-cent books where the seller makes a tiny spread on shipping and handling now common for titles that are plentiful, especially popular fiction and popular science. Other times there is one copy, maybe two, on the net, and the seller with it decides to price it to the sky (one or two thousand US$ is not uncommon). These usually sit there for a while.
And, i would conclude this deep scientific inquiry about BQP on a more serious way, in front of such scientific confusions and ridiculous argues on its site, asking an embarrassing question.
Can somebody provide evidence that Mr Bybee had any degree in physics and had ever worked for the US navy ?
As a secret agent myself, i asked Miss Moneypenny and Mr. Q and they were unable to find any trace of such a man as a provider of the US army neither traces of any BQT in the plans of U.S.submarines we have in our possession.
Can somebody provide evidence that Mr Bybee had any degree in physics and had ever worked for the US navy ?
As a secret agent myself, i asked Miss Moneypenny and Mr. Q and they were unable to find any trace of such a man as a provider of the US army neither traces of any BQT in the plans of U.S.submarines we have in our possession.
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I don't either, but twice this week "asymmetrical waveforms have DC" was stated as an obvious fact. In xDSL as in audio large plus or minus crest events are not matched by the opposite polarity but the time average is 0 (especially in xDSL where there is complete galvanic isolation on both ends).
It rather spoils the fun when we have to be continually explaining (and even justifying!) basic physics/maths/EE to people who either ought to know better or can't be bothered to learn the basics. Perhaps the forum should have a pedagogical area for such stuff, so the rest of the site does not have to be clogged up with teaching about elementary circuit theory, Fourier, algebra, calculus, feedback, stability etc. Teaching is not much fun when the pupils are convinced they know better than their teachers.scott wurcer said:
There is plenty in audio to have genuine arguments about, but we get bogged down in nonsense like "asymmetrical waveforms have DC".
Have-you noticed that scientific oriented people continuously try to increase and correct their knowledge, while so called audiophiles and other people, living in a world of magic, just continuously try to comfort their believes, even when they hurt the most elementary logic ?
As far as i'm concerned, i have much fun, observing this human comedy. How the majority of people use on a daily basis objects they do not understand, from cars, to refrigerators.
In the between, there are few people that have some kind of basis, and still continue to believe in magic. Means experiment and do not try to understand.
Audio is a marvelous world for this sociological observation. Real science fiction.
Everyone, this is advanced understanding that is brought up in senior year at major universities in electronic engineering. Dr. Don Pederson taught me that, about 40 years ago. Dr. R.G. Meyer taught that to Ron Quan about 35 years ago, and I put up a couple pages of Ron's class notes to verify what I already know. (the added comments are HIS)
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Now that everyone is listening, HOW do you create DC in the power line? OK, just take a power diode, 5-10A should do with 400V min rating, then put it in series with an old fashioned light bulb and plug the combination into the wall socket. Try it! It is a test that we use at Parasound to find or verify noisy power transformers.
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I have a variac I use to adjust the power of a heated footrest. Nearby is a torchiere floor lamp with a three-position switch, off-low-high. The second position inserted a diode in series with the incandescent lamp (the switch contact in that position, or the diode, has failed now).
It was easy, until it failed (open-circuit) to notice the effect of position two, due to the quite audible buzz out of the variac. I did not attempt to measure the d.c. offset, but the noise was very irritating.
If I try to piece it togehter, both sides on this argument are equaly wrong because both sides are equaly right.
In a practical application, like John showed, with a fixed ground or neutral, by clipping or distorting a waveform assymetrically, you create harmonics and a DC offset,compared to this fixed ground (the area under the wave form above and below the zero will not be identical).
In a mathematical representation as mentioned by Scott and DF96, you can stack sines in order to achieve the same wave form. But the zero then floats (by method it is there where the area under the wave form above and below the zero are the same). So there is no DC offset.
Different perspectives.
Not the same waveform, I would consider a diode a pretty gross non-linearity causing modulation products that are not possible by simple linear addition. You square a sine wave and you a second harmonic plus DC no simple addition of sine waves of any frequencies will give the DC component.
EDIT - Here's a previously published example, this waveform has no DC and is highly asymmetric.
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JC, please tell us what you want to call the circuit you posted as phono.pdf? The one that you told us was caned by the reviewers.
I'm glad you've finally remembered what 'JC-2 mk1' means to you.
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I can well believe that musicians did well in these tests.
Contrary to some other researchers, my nearly 20 years of Double Blind Listening Tests show that musicians are usually above average in their sensitivity to faults though none of my tests explored Fourier uncertainty. This probably cos I was more interested in testing with music.
Sadly, "Golden Eared audiophiles" are well below average compared to the man or woman in the street. In fact, in nearly 2 decades, I failed to find a single Golden Pinnae, whose discriminatory ability didn't vanish miraculously, the moment the lights were turned off and he couldn't see what he was listening to.
But I've been often surprised at the aural acuity of true golden pinnae. There have been times when some of my Listening Panel could reliably pick up differences which my poor test equipment in those days could hardly pick up.
And of course there are the true 'Elite' like JC who don't even have to listen to a product to tell you what it sounds like. They can do it by simply looking at the price tag and the labels on the evil OPAs.
So lets not confuse the hearing acuity of some true golden pinnae from the ravings of deaf Golden Pinnae audiophiles.
I'm disappointed that my request for suggestions of true golden pinnae has not produced any recommendations even among this august company.
Surely there must be people who can (or think they can) distinguish Blowtorch from evil 4558 devices in a Blind Listening Test bla bla and are prepared to interested in testing this proposition ?
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JC, while you have provided some useful practical pearls of wisdom on testing power transformers, you might like to re-read Electronic 101 or even the notes that Quan so kindly restored to you.
There is much there about even harmonics & DC that would help you understand what actually happens to transformers. I also recommend Wireless World back to the original Williamson articles and particularly anything by Great Guru Baxandall.
If DF96 starts his "basic physics/maths/EE ... " thread, you would be well advised to take advantage of this.
There is much about ".. elementary circuit theory, Fourier, algebra, calculus, feedback, stability etc" that you could profit from if you refresh your basics.
In the meantime, close study of datasheets by true gurus would help you make less mistakes with evil OPAs.
Scott, this example only proves what I already thought. Ofcourse there is no DC here. How could it be after galvanic uncoupling? The zero floats.
I thought all waveforms could be produced by simple additions of sinoids, including those caused by diodes clipping a sinewave. You can mathematically arrive at the same waveform that John created with his test setup. But then ofcourse DC does not show up. Isn't this what you originally meant?
It need an infinite time to can assert if there is DC or not in a signal .
Neither Scott or John can win this contest.
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