Position Encoding.

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The academics that come out on top get Nobel prizes and other benefits that are noticed outside universities, and the work that gets the prizes sometimes shows up in the devices we use, and the stuff that we run into when we end up in hospital.

Universities don't exist in isolation. They don't work the same way as industry or commerce, but they produce stuff that is useful in industry and in commerce.

So what? They are competing for status in the business of finding out how the world works. What they find out has been useful to the rest of society in the past, and can be expected to be useful in the future.

You compete for orders in a "society" that is just as "closed", and your status (and your income) depend on how many orders you win. "Citations" aren't directly comparable with orders, but if you've written a paper that other researches find useful enough to be worth citing, you've done something roughly equivalent to designing a system that is useful enough that people will pay money to get hold of an example.

I've got one paper on a particular design of a temperature controller that used a Peltier junction to control temperature to +/-1mK. Twelve other poeple have found it useful enough to cite it. That's real too, though a lot less profitable.

I understood it well enough when I was doing it, and I doubt that I understand it any less well now. What you fail to understand is that there are a number of worlds beyond electronics, and if the academic world - for instance - didn't exist, there'd be fewer people around to buy your electronics, and fewer components around for you to build your electronics with.

Glacially slowly.

-- Bill Sloman, Nijmegen

i understand how it can be a single track (of half the transition frequency) and two offset (by 90 degrees) optical sensors.

what are the mask? are they just alternating 0 and 1 bits ore are they Tim's MLS with a 0 stuffed in? i don't get this mask thing, unless you're measuring the total open path throughout the whole period.

but the masking operation is AND and i think, for the MLS (and i have

*no* idea if this would work with the 0 stuffed in) is that XORing an MLS with a copy itself possibly rotated will result either in all 0s (if the two copies are coincident) or that very same MLS but spun around another wild-assed random number of bits. now with that same sequence backward, i don't know what it would do.

but the bit transitions won't happen perfectly simultaneously but close to it. won't you get momentary glitches?

something i'm not getting.

--

r b-j                  rbj@audioimagination.com

"Imagination is more important than knowledge."

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Not that I've noticed. I do know stuff about subjects where John Larkin is lamentably ignorant, but there are a number of rightwing nitwits on this user group who are even more ignorant than he is, and I'm not the only poster who corrects their ignorance.

-- Bill Sloman, Nijmegen

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You don't use two tracks to get quadrature - you use one moving track, but inspect it with two detectors looking at the same track through two different segments on a single static mask. __ __ __ __ __| |__| |___| |__| |__

in-phase mask quadrature mask

anything more complicated, and you've got a sustem that has to be alinged and can slip out of alignment.

The third detector on the pseudo-randon bit sequence has to respond to a single element, which probably means a lens and hood to cut out stray light - the in-phase and quadrature detectors can happily average over a couple of elements (if the relevant sectors of the static mask are wide enough) whch makes them easier and cheaper to realise.

The clock edges aren't perfectly evenly distributed around the circle. The bit of the track that's closest to the actual centre of rotation travels past the detectors faster than the bit that's farthest away.

-- Bill Sloman, Nijmegen

So now you're the messenger that carries the burden of all those poor souls that can't conform to your statistical form of thinking.

Guess you've given up on your end, to many around you like yourself. This must be an escape for you.

Jamie

With only two tracks? I don't think so, have you ever looked into the construction of an encode lately? Or maybe at all?

If you can't get 2 tracks/lanes to line up in a basic Q encoder that is only on the average of 1024 PPR, something is very wrong.

Did you also fail at mechanics, too?

Do you know how to change your own tire?

Jamie

Slowman is keeper of the wipes ;-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

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I wonder what Jamie thought "statistical form of thinking" might mean? Who cares?

lf.

What "end" would that be? All the people that I meet socially read European newspapers (often on the web) and have a tolerably accurate idea of what is going on. About half of this user group seems to rely on Fox News for its general misinformation.

From what? You won't have a clue, but that won't stop you from dreaming up some absurd suggestion. Not perhaps as absurd as your claim that you are organised enough to look after a dog, but something nearly as silly.

-- Bill Sloman, Nijmegen

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I designed the new VME LVDT/synchro simulator module in four days last week, 19 sheets of schematic. And skiied three half-days too.

John

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Score one for Jamie. Sloman could not make it either as an academic nor as a real engineer. And now just whines just like a dole dependant twit.

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Yes and no. Average units are not accurate beyond 16 bits, specialty = ones are good to almost 24 bits. See Farrand inductosyns. See also multispeed systems with gear ratios of 36:1 and 72:1, a bit antique now.

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What you post might qualify as vulgar nonsense if your output was coherent enough to be vaguely intelligible.

Which is an classic example of your incoherent nonsense.

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Your imagination is running away with you again. I don't scratch my head over your incoherent idiocies - I noticed that you were cognitively challenged some time ago, and confine myself to pointing out this out whenever you post yet another screenful of impertinent rubbish.

-- Bill Sloman, Nijmegen

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So much for joshephkk's judgement

I got the Ph.D. and I've published papers in the peer-reviewed literature that have been cited - I didn't make it big as a academic, but I certainly got to first base.

Check the patents and the published papers. I was a "real engineer" for some thirty years - if I didn't make it as a real engineer you've got a totally bizarre idea of what constitutes "making it".

Really? I stopped getting unemployment benefit when I turned 65 - four years ago - so I'm obviously not dependent (note the spelling) on it, and telling nitwits like you that you are posting nonsense doesn't actually constitute whining, even if it does get on your nerves.

-- Bill Sloman, Nijmegen

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Lots of copy and paste ... you might impress somebody who hasn't done that kind of stuff.

-- Bill Sloman, Nijmegen

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Have you? I put together the angle sensor on the Fisons Applied Sensor Technology IAsys machine, and it worked just that way.

Cush R, Cronin J M, Stewart W J, Maule C H, Molloy J and Goddard N J 1993 Biosensor Bioelectron. 8 347=9653

If you think you need two tracks there's something wrong with your brain, but we knew that anyway.

Not a course I took, or could take, somewhat to my disgust.

Obviously - I even reground the valve-seats on my old Peugeot 404 back in 1979, which requires a little more mechanical insight, though you may not be aware of this.

-- Bill Sloman, Nijmegen

[snip]

A funny story along the same lines as this post; we have a Yang lathe which cuts some magnetic motor parts to 1 mil. It's an ID bore operation and then a finish pass. About six months back the parts were measuring +/- 3 mil in the x-axis random. We called a technician to come in and fix the problem. After two days he decided that we needed two new encoders and all of the parameters changed on our machine. We swapped out the encoders, changed the parameters he wanted, and no change in the problem. He's sure because it's random that it is some software glitch in the machine. Nope. Our machinist starts to look in at the problem at this point. Turns out the turret is connected to the x-axis ball screw with a bunch of bolts that were under torqued. When brought to specification we're back to 1 mil. I guess you don't need to rewind the motor before you check the fuse.

Mark DeArman

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Being mechanically challenged, you have no idea whether it would be
harder to build than a conventional absolute encoder, and he's already
stated that he might have to roll his own, so that's irrelevant.

--
How would you know?

You're not really a circuit designer - as evidenced by the fact that
for as long as you've been trolling these groups you pride yourself on
never having used a 555 and therefore can't, by your own admission,
appreciate the subtlety of using a 555 cleverly and understanding its
versatility.

--
Casn?