On Thursday 26 April 2007, Tim wrote: >Tim: >>> Sounds like they need to, also, employ someone who used to be a teacher. >>> Someone who's used to the idea of having to train, as the main thing >>> that they do. > >Gene Heskett: >> On the face of it, that is a good idea. Till that old saw about >> "those who can't do, teach" comes crawling up out of the back of my >> mind, having had it quite amply demonstrated in my nearly 57 years of >> chasing electrons for a living. The other corollary to that is that >> those who can do, and then try to teach, have a hell of a time trying >> to reduce the language to something that actually works for TV-101 >> classes. > >;-) Generally, we had the opposite problem at college. Teachers who >learnt electronics at college, then became teachers, were worse than >those who worked in the industry, then became teachers. For one thing, >they knew the difference between theory and practice. > >I could never get any lecturer to give a sane explanation of AM. They'd >tell us that the carrier was a fixed amplitude. I'd argue that AM was >modulating the carrier, therefor it has a varying one. I'd even >demonstrate by cranking the pot up and down to give a 1 Hertz AM. None >of them could give a reasonable explanation. Yes, they could give >strange ones, but none that fitted the situation demonstrated. > I suspect they got lost someplace in the vector math, or the fourier transforms. Both are damndably hard to explain to someone, like me, sorely lacking in the math background to understand it. One of the disadvantages of having only an 8th grade formal education. Beyond that, I'm self taught, and have occasionally caught the teacher out & made him go back to the books. :) >Yes, I know that you can put a 1 kHz signal on top of a 1 MHz one, and >then filter one away from the other. Theoretically, that's fine. But >it doesn't get around the fact that I had grabbed the pot and changed >the carrier level. It sure didn't have a constant carrier level in my >hands. Yup, sideband analysis tends to break down when the circuit to do the analysis is not physically realizable. The hand on the pot has the final word anyway. >-- >(This box runs FC6, my others run FC4 & FC5, in case that's > important to the thread.) > >Don't send private replies to my address, the mailbox is ignored. >I read messages from the public lists. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) There is something in the pang of change More than the heart can bear, Unhappiness remembering happiness. -- Euripides
