John Cuthber

You seem to be making my point for me. There is only one voltage on the antenna at any time, but you can resolve it into two signals, one AM and one FM. And, as I have said before, you can recover the FM signal using an AM receiver. Clearly you can resolve the AM signal with an AM receiver too. So what signal does an AM receiver get in this case? The answer is a distorted mixture of both

Still waiting for the evidence of damage.

It seems we are using different definitions. I'm taking a rather simple view. If the frequency spectrum (it's never just one frequency once you have a carrier and a signal) changes "in time with the music" then there's frequency modulation happening. You seem to think two mutually exclusive things (a) It's only FM if it's a shift in the carrier frequency that is (ideally) proportional to the signal amplitude and (b) It's also FM if it's a shift in the carrier phase that is (ideally) proportional to the signal amplitude. Well, if b is true then a isn't; and once you accept that not all FM is the sort that's used for commercial stereo broadcasts, then ruling out AM is an arbitrary decision.

Set up a poll and find out. Or, better, you could actually find some evidence of damage. Oh, hang on, if I say that you will point out that there really are some problems (at the very least some members of the species homo sapiens have been greatly inconvenienced.) So, it looks like I'm stuck with being scientific about i t and not claiming that there are precisely zero issues. Feel free to mistake that for weasel wording. Please feel free to gainsay my assertion that there's "not much evidence of lasting damage". And here's my previous "weasel wording" on it.

They talk about AM and FM, partly, because those are what the receivers expect and partly because it's a simplification- a model. The signal that arrives at the antenna doesn't know which "sort" of signal it is. And, as I said, you can listen to an FM signal with a (slightly detuned) AM receiver. There are other types of modulation too, but the idea is a bit meaningless until you try to "decode" it. And, sorry, but it's not much to do with errors, variances or normal distributions. Those make the picture more complex

OK, what does the spectrum of, for example, a 1 MHz carrier, amplitude modulated by a 1 KHz sine wave look like? Not all the power is at 1MHz is it? So, some of it is at other frequencies (1,001,000 Hz and 999,000 Hz to be specific). So you have modulated the frequencies you transmit. The distinctions are artificial.

This may seem mean, but why would the best schools want you?

In general, if an attacker can access your computer he gains considerable access to your data.

My point is that any FM signal is AM and any AM signal is FM. Since the distinction is artificial, the combination is too.

Good question. The same point has been raised for another type of door. http://en.wikipedia.org/wiki/Scissor_doors#Disadvantages

If you (and the bits of metal) are in the Earth's magnetic field then both of them will be magnetised (obviously, one more that the other) so the alignment with the North South line won't work.

Well, I guess we are screwed.

OK, who would you suggest? imagine you are the one in front of whom the spaceship lands , the alien comes out and says "take me to your leader" (as they do in all the dodgy sci fi movies). To whom would you direct them?

Getting that wrong once suggested that you are uninformed. Getting it deliberately wrong a second time, and after it has been pointed out, suggests that you are too dumb to learn. That, combined with toxic chemicals, doesn't bode well.

"Combined amplitude and frequency modulation is used all the time." "More precisely, a constellation modulates simulatenously the amplitude and the phase" "In that sense, a phase modulation is also a frequency modulation" Sure, and in that a carrier amplitude modulated by a sine wave gives the carrier with two additional frequencies (the sum and difference frequencies), amplitude modulation is also a frequency modulation. So there's no difference to discuss. That's my point; an antenna will pick up a wiggly voltage. How you interpret that voltage depends on how you think the signal is being transmitted. If you try to do conventional AM and FM at the same time they will mess each other up. OK, you can do PSK and if there's enough S/N available you can add AM. But you are doing a totally different scheme. It's not AM and FM at the same time (at least not in the sense of the OP's question). Of course, from another pedantic point of view, if you take an FM signal, and broadcast it from an antenna then, unless that antenna has a precisely flat transmission response (and none does), the signal will always be amplitude modulated too. All FM signals are also AM.

That's the unreliable assumption.

Yes, you could. And that signal would be essentially a voltage changing with time. It would be centred on the carrier frequency and it would have side bands. Now imagine that I switch off the AM part of the transmission, I get a signal that's centred on the carrier frequency and it would have side bands. OK so, instead I only switch on the AM transmitter and I get a signal that's centred on the carrier frequency and it would have side bands. I'm not sure that the two receivers can unambiguously distinguish between the two sorts of signals. By way of a "hand-waving argument" in support of this, i invite you to consider the technology of synthesisers (as in electronic music) The early ones used am synthesis and could, in principle, mimic any sound. The newer ones use FM and can in principle, mimic any sound. I think the receiver would be in the same position as the human ear listening to 80s pop. It wouldn't know (and couldn't, even in principle know) whether the signal it received was AM or FM. As far as I can see, you have run out of variables.

Show us.

You might not have, the rest of us know how to store electricity http://en.wikipedia.org/wiki/Capacitor But there's not much demand to store electricity since you can generally store the energy from which the electrical power is derived..

The usual answer relies on an assumption that may not be true.

What frequency do you tune the am part of the receiver to? Also, since it's possible to receive an fm signal with an am receiver, how are you going to disentangle the two signals? http://www.daenotes.com/electronics/communication-system/fm-slope-detector

After a while (if nothing else happened) there would be a positive charge in the cell that would repel any incoming ions to such an extent that the pump would "stall"

It's absorbed into the bloodstream and, in due course lost as sweat or urine.

It won't boil the water off from the solution, but it should be hot enough that it will evaporate quite quickly. It will be quicker if the container with the nitrate solution is shallow.

My machine seems to let me spell colour and labour correctly. Windows 7 and Chrome.