Frequency down-conversion with passive circuitry?

The two currents don't have to be at the same impedance level, so you're quite right.

Cheers

Phil Hobbs

Sorry to be a bit absent after my first question, but we're gearing up to restart the accelerators here by the end of the month and work took precedence.

Phil's last remark is precisely what I was after. I'm perfectly OK with nonlinear inductors or capacitors instead of diodes, too.

The reason I asked this question, I must confess, is that in an article I came across recently, the authors flatly state that it is impossible to do so without invoking quantum physics theory. Clearly, if it is possible using some non-linear passive circuitry, this affirmation is false. Now I must hunt down an example...

For those interested, the article I referred to is: B. Pearson, D. Jackson, "A hands-on introduction to single photons and quantum mechanics for undergraduates", A. J. Phys. 78(5), May 2010.

Thanks everyone for their contributions.

Regards, Jeroen Belleman

On a sunny day (Wed, 12 Jan 2011 22:47:25 +0100) it happened Jeroen wrote in :

Quantum mechanics is crap, bullshit, phantasy, nonsense. CERN is a joke. ITER is idiotic. LIGO is insane.

Blame it on... misunderstanding Planck's constant. So blame it on Einstein.

No I am not interested in crap.

Sorry for the harsh words, but not really, somebody has got to say it, and I just did. have fun with your 'accellerator'. It will never do anything for anybody, except keep work for the industries that build these phantoms.

Only thing CERN is good for is a bomb shelter.

Q.

BTW the earth is not flat either.

And it works. So far, it's the only thing that works.

John

I should invest some time in a rebuttal, but I'm not really well armed.

Let me put it this way: CERN draws scientists to Europe. Science is at the basis of all innovative economic activity. Accelerator physics has spin-offs that find use in other places. Proton and carbon beam therapy against cancer, imaging radiation detectors for X-raying whole trucks, synchrotron light sources for all sorts of purposes. Technologies developed for or by CERN or other physics institutes, and which would not have been available otherwise at a reasonable price, find use in other places: The World Wide Web, very accurate DC current transformers, cryogenics, super conductivity, scintillating plastics and crystals, big magnets, precise surveying, radio frequency equipment and techniques, vacuum, etc, etc.

CERN pays my salary, so it's certainly no joke to me. It's a fascinating place to work. Apart from the technical aspects of the place, there is the fact that all cultures and nationalities of the world are represented here, working closely together for a single purpose: Understanding how the universe works.

I'd love to pull the rug from under quantum mechanics.

Jeroen Belleman

On a sunny day (Thu, 13 Jan 2011 00:20:55 +0100) it happened Jeroen wrote in :

True But what sort of scientist? People who write tissue paper PhD thesises about wormholes, time travel, and what not. Not to mention string theory.

True But remember that many inventions were made not by 'scientists' as certified by that scientific community, but by industry itself, many just by accident, like high temperature superconductors for example. The guy who invented the wheel (first used it), was likely not a mathematician, neither did he know about PI, but sure enough some mathematician claimed it later, same for related inventions.

True

You do not need CERN for that, nuclear reactors are used.

Xrays have been around a long time.

True.

This is a funny example, I am not alien to accelerators, but I will not go into that. I remember in FOM, in Amsterdam, the linear accelerator project, people has 10% time for free research, projects of their own choice. I think the idea of hyperlinks was probably born in the same way. It has nothing to do with the 'goal' (if any) that CERN had or has. And internet comes from a mil source.

Kamerling Onnes was there first, nothing to do with fathoms like CERN and accelerators. Hall effect is not from research at CERN I think, and there are other more precise ways to measure DC current that were at the most further developed, but did not originate, in CERN.

Sure electronics equipment is designed and CERN is a large market for manufacturers of exotic electronics. Scintillators were used long before CERN was build for surveying (looking for uranium for power and bombs).

This the point, it is a self serving cycle, an infinite (well sure it will end one day) loop. Like the defence industry having a need for tensions and war, and it using politics to create that, CERN and its associated confusion projects creates jobs, but really when you think about it, after all these years, still no clue what gravity is, how it relates to the other forces. say they find the Higgs, then what? Then they will ask for a bigger accelerator, and if they do not see Higgs, then they will ALSO ask money for a bigger accelerator, IIRC a linear one is next one the wish list. DO THEY NOT SEE THERE IS NO END TO THAT FOLLY?

I see it this way (and it was not even my idea, I heard this as kid from a(n ex) director of a large accelerator (he left because of that), you can shoot marbles all your life, and with ever more energy find ever smaller fragments, but you will Never, NEVER EVER gain understanding of the universe that way. What fails is the insight, it is just a dumb game of making matrix with ever smaller fragments, It is like shooting cars against each other and thinking that from the fragments you will understand a modern combustion engine. I want to add to that something myself (to that earlier statement): "If you cannot do it with those small particles on the workbench, then you cannot do it in a machine the size of the universe (or city)."

Oh yes, I had great fun designing some parts of .. accelerator. But the real fun was the 10% free projects, that really did it for me.

Personally I do not care, but something is clearly wrong there. I am to old likely to see a new theory that works and is more compatible with nature. I *would* like to fly to far away planets at a speed > c, say under constant 1 G acceleration, visit the stars. We are all stardust -- and life is everywhere. past present and future, what is it? Something beautiful exists, it is also inside us all.

I've always had this kind of nagging question in my head - does a diode really qualify as "passive?" Maybe it's just that they're so blatantly nonlinear!

Anybody wanna start a holy war over it? >:->

Thanks, Rich

No power added == passive (ever heard of "passive RFID tags"?)

Too late.

Holy s*it!

Doesn't DC count as 'lower' frequency?

Well, the op was asking for f/2 and such. That's a more interesting problem.

John

This

ftp://jjlarkin.lmi.net/SubHarmonic.gif

worked first try. I'm sure it could be tweaked for more output amplitude. The x1000 gain is just there to zoom up the output amplitude for graphing.

I'm thinking the amplitude is low because the frequency is low, namely Cdiode

Works better with slightly smaller C, maybe 0.994 uF.

John

A ringing current generator used by the U.K. Post Office Telephone service in the late 1950s and 1960s used a selenium rectifier and resonant circuit to generate 16.666 c/s to operate telephone bells.

That's not the point. At the time, only research institutes and universities had the need to disseminate information *and* the hardware to do so, creating a fertile environment to build fancy software to make it practical, fun, even. Neither the military, nor any commercial enterprise would have made this freely available, but CERN did, thus spawning the explosive expansion of ubiquitous networking we have witnessed.

I was referring to DCCTs, invented by Klaus Unser in 1969. He was at CERN at the time.

Yes, but again, that's not the point. CERN's massive use of that technology makes it more accessible for the rest of us, because it provides the impetus to develop cost-effective and innovative solutions to technical problems.

When Ampere and Faraday played around with electricity, no-one could have guessed what use we might make of it two centuries later. It's like that with basic research: It looks pointless at the time it's done, but a few decennia later it may change the face of the world. That's what makes it worthwhile.

If I may slightly misquote Arthur Clarke, or was that Mark Twain: "If we had had no research in the stone age, we might have had superb flint axes, but no one would have invented steel".

Jeroen Belleman

On a sunny day (Thu, 13 Jan 2011 14:31:30 +0100) it happened Jeroen Belleman wrote in :

OK, never met him. I presume you are referring to the zero flux DCCT (fluxgate with feedback for all I know).

This is over simplified. Sure you need research, as you point out. But it is the market forces that push these, even CERN is financed by taxes from profits in the markets. These market forces and the research BY COMPANIES (IBM researchers found the high temperature superconductors), is what pushes to ever better solutions. That is why the USSR was behind, no push from market forces. As to that 'www thing', the only 'invention' was the 'hyperlink'. Sure the C parser code was available for free from the CERN site, I downloaded it and had a good look at it when I wrote this newsreader (it has some html parsing, see the headers), many many years ago. But from there it was pushed by the commercialisation of the web. We had gopher, ftp, etc, what not.

Right, basic research is OK, but it should stay sane, and in proportion to results. CERN and ITER are out of proportion, and have no results. Just a little bit of anti-matter (mil was interested that was why so many physisicks were cloned after WW2, because it was thought it would help DEFENCE, and maybe [almost] free energy) fusion). That failed, all we got was brain dead parrots who parrot Einstein's equations and write tissue paper about string quartets and wormholes. So these projects CERN, ITER, should be killed, LIGO too (will never find anything as the basis is wrong), and more sane objective goals should be set by governments for research. On the issue of fusion power it may help to web search, some time ago I found that there is a mil project that is in an advanced stage that claims to have a working fusion power plant for use in ships much sooner than the next '50 years' that current mainstream seems to suggest.

I have nobody to quote but myself. Scrap CERN, ITER, LIGO. If you cannot do it with those small particles (fusion power) on the desktop, then you cannot do it in a machine the size of the universe (or city).

:-)

No it isn't. It is scientists curiosity about nature that gets the big breakthroughs. We would never have had lasers if it had been left to beancounters and market forces. When they were first invented the price was ludicrous and required large near perfect ruby crystals and huge flash guns. Now every CD and DVD has one inside as do laser printers.

You can never predict where blue sky research will find applications.

They were looking for better piezoelectric materials at the time. Same with 3M and post-its the new glue was supposed to be super strong but it turned out to have other useful properties. It could easily have been killed at birth if the inventor had not found it a niche.

Do you not remember Spudnik and Yuri Gugarin? Incidentally this year is the 40th anniversary of the first man in space.

The hyperlink was invented in 1968.

The invention was the synthesis of global URL descriptors and a self consistent text based way of specifying hyperlinks and content in a graphical form. ISTR the Apple Mac help system was an influence on the early web and that dates back to the mid 80's. Tim Berners-Lee put it all together on the Internet and the rest is history. It was a genuine spin-off from CERN no matter how much you may dislike the fact.

His intent was to make it easier for researchers to exchange data. Handling the huge datasets from HEP has also spawned developments in mapmaking - descendants of the same hardware that used to digitise HEP film records in the 80's went on to digitise all the worlds maps.

it

parsing,

ftp and gopher all predate the www. Most bulk transfers in those days were done overnight as batch jobs to avoid upsetting daytime users.

results.

How can you possibly know in advance what the results will be? The whole purpose of doing fundamental research is to find out something new that is presently unknown or test the predictions of theory.

They do have plenty of results of interest to high energy physicists and cosmologists. And the spin-off technology of synchrotron sources with beam wigglers are now being used to power the coherent UV sources for the next generation of chip making.

If you want to scrap something then the ISS is a pretty good candidate. It is completely useless as a telescope platform and the "science" being done in it would not look out of place at a school science fair.

Why is it that every nutter on the planet who cannot understand the physics insists vehemently that Einstein was wrong?

Just because you don't understand physics is no reason to scrap them.

Have you ever noticed that the sun seems to manage to sustain a pretty reliable thermonuclear reaction. Astrophysics can put a pretty good bound on the minimum mass needed to have a star light up about

Regards, Martin Brown

Yes, exactly.

That's too simple. Sometimes we develop something and ask industry to build it for us. Or we may buy something ready- made. But often, for exotic technologies, it's some of both in varying proportions. That's where it gets interesting, because those technologies will then no longer be so exotic.

Yes, that what I've been trying to say: Research invents something, and then commerce takes over to make money from it. That's the way it works, and that's the way it should be.

results.

You are quite right. However, the right proportion is much a matter of opinion. The Netherlands' contribution of about

Jeroen Belleman

Ah, that's an interesting story...

Neither US no Russia were planning on launching a spacecraft.

USSR developed the H-bomb of the layered cake concept, which was much heavier then the competing Ulaf-Teller design of the US. However, it took several years for the US to make a real weapon of this concept; whereas the simple "layered cake" bomb was already available to Russia.

So, the russian military set the design goal of the ICBM with the throw weight of ~5 tonns. That was a difficult problem for those days. The development of the R-7 missile was a disaster; many crashes; they could hardly hit a target of 100x100km size. The government and the military started growling; there were talks on firing the management of the project or pulling the plug at all. One of the designers suggested to launch an object to the orbit, just to keep the government happy. So they did. No one could expect that would raise such a tremendous public response! Especially as the second stage of the ICBM flying in the orbit could be seen with the naked eye (the actual payload "Sputnik" was too small to be seen).Few yeas later, the modification of the same R-7 ICBM was used to launch man in space. //----------------

So, the "Sputnik" and Yuri Gagarin were the unexpected side effects of the heavy ICBM development as opposed to the fundamental scientific recearch with the goal to put a man in space.

Vladimir Vassilevsky DSP and Mixed Signal Design Consultant