Debouncing....at About 1Mhz

If you do understand how it works, why are you challenging me to prove that it works?

It does work. And, as I noted when I posted it, it was a way to get the prop delay down to 1. And as I also noted, it has constraints that would lead me to prefer my first circuit.

I suppose all that makes me a leftist weenie.

You know, in any given half-hour, me and one of my guys, with a whiteboard, may come up with 50 interesting circuits. Most are flawed in some way, many are plain goofy, but the process usually leads to something that's both elegant and reliable. Some people just poison a process like this. People like that should be airline mechanics or something, where eveything must be exactly the same, by the book, every time.

John

Reply to
John Larkin
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So? You want me to praise the "flawed" ones ?:-)

I guarantee that I have generated far more "flawed" ideas than you. I just toss them rather than running them up the flag pole to try to impress some newbie.

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave
Reply to
Jim Thompson

I look at circuits like I look at women. Pretty... Nice... Gorilla... Plain Jane. Wow she's hot!

I'm not expecting to always see 'hot' circuits on here. I don't know yet how good the latest 'JF' release is but I give it a 'pretty' rating.. :) She might be a bitch..buts she's pretty. :)

D from BC

Reply to
D from BC

I want nothing from you. Absolutely nothing.

John

Reply to
John Larkin

--
Especially, it seems, criticism.
Reply to
John Fields

Doesn't matter. But if you're wrong, I reserve the right to have fun with it.

John

Reply to
John Larkin

--- So, you think that ridiculing is fun? What does that say about you?

Of course it matters.

It's the whole point because you have an overriding obsession with being infallible and when you're shown not to be by valid criticism, (especially, OMIGOD, when that criticism emanates from, of all places, a newsgroup, who's members you obviously view as being your inferiors) you get nasty.

Yet you try to pretend that you're such a nice guy that you'll brainstorm with your minions, peer-to-peer. However, since you're paying their salaries and they're easy to shut up, that's not really peer-to-peer and it doesn't really count.

What's peer-to-peer is _here_, and I've seen, time and time again when someone disagrees with you that you leave polite discourse behind and start to couch your dialogue in a rather more sinister tone.

As if you were a corrupt D.A., for example, hinting to a critical newspaper reporter that a rather painful investigation of his life might ensue if the criticism isn't rescinded or, at least, dropped.

Stretched, perhaps, but I like to use "Reductio ad absurdum" to make a point, if you got it.

-- JF

Reply to
John Fields

--
Hazard free?  There still remains the RFI issue from all that
chatter, which you haven\'t adequately addressed.
Reply to
John Fields

Some people need ridiculing. Some practically beg for it. I'm almost always nice to polite, sincere people, even dumb ones. Fatheads, on the other hand, are fair game.

I'm not infallible, but I'm usually right. That's because I'm careful, and I check my facts before I make definitive statements. Anybody can do that if they want to. Our electronics usually works because we assume that we're not infallible, so we check our own and each others work before we etch boards. Anybody else can do that, too.

What I have an overriding obsession with is designing great electronics. That's absolutely incompatible with overconfidence. Concepts require arrogance, but implementation requires paranoia.

I wish they would shut up sometimes. I get very little deference around this place. I get yelled at fairly regularly, and my decisions prevail only if I can convince people they're a good idea. Geez, there's no point in having employees if you still do all the thinking.

What's that saying about heat and kitchens?

I'm not a DA. I can't arrest anybody. All I can do here is type, just like anybody else.

Grow up.

John

Reply to
John Larkin
[snip]

Not necessarily so. Isn't it L'Hopitals's rule...

lim f(x) f'(x) x->0 ---- --> ----- g(x) g'(x)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

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| 1962 | America: Land of the Free, Because of the Brave

Reply to
Jim Thompson

I was referring to timing hazards, which all of the hairball circuits have. And I can't understand your fears about running signals through gates. How are you ever going to do logic if you're afraid to run signals through gates? "All that chatter" is in fact the input signal.

Fred doesn't design things. He's said so. He sure didn't take a shot at this problem. Mostly what Fred does is criticize designs for emotional reasons, and look up a lot of old papers and cite them.

He doesn't design.

John

Reply to
John Larkin

--
Of course, according to you.

But, we\'ll all have to wait to see your "solution" until...?
Reply to
John Fields

John Larkin snipped-for-privacy@highNOTlandTHIStechnologyPART.com posted to sci.electronics.design:

If you think so build and test it, or SPICE it. Show us the results.

Reply to
JosephKK

Hell, I've already done the only circuit that really works.

Playing with circuits is no fun when the other guys just play couch potato.

John

Reply to
John Larkin

[snip]

My circuit doesn't work? Sure it does. I captures the first transition just as requested by the OP.

Oh, Dear John, You've become a smug SOB on a level with Bloggs ;-)

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave
Reply to
Jim Thompson

--
Hmm...

I guess you haven\'t gone to the trouble of running the simulation
that I provided.
Reply to
John Fields

I'm surprised that you don't seem to know this, but if you have a signal with sharp edges then, at each transition, a multiplicity of harmonics will be generated and radiated into space.

Look at it like this:

. _________________________ .FIN ___| |____________________ . _ _ .NFIN____| |_______________________| |_________________

where FIN is the input signal and NFIN represents the spectral products generated by FIN's transitions, i.e. noise, if you have no use for the harmonics.

Now, if that signal is delayed by sending it through a gate:

| \\ FIN>---| >--->DFIN | /

we'll have:

. _________________________ .FIN ___| |____________________ . _ _ .NFIN ___| |_______________________| |_________________

on the input to the gate, and:

. _________________________ .DFIN _______| |____________________ . _ _ .NDFIN________| |_______________________| |_________________

on the output of the gate.

Notice that there are now twice as many noise pulses as there were before, since there's one on each of the incident as well as the delayed transitions.

The chain in your circuit: (View in Courier)

N1 / +------------------------A | N2 Y---CLK FIN>--+-A / +--B Y---A /N3 | B Y---A | | B B--+ | | Y \\ | | | N4 GND>----+------+------+

(assuming equal gate delays) generates noise pulses that look, roughly, something like this:

. _________________________ .FIN ___| |____________________ . _ _ .N1 ____| |_______________________| |_________________ . _ _ .N2 ________| |_______________________| |_____________ . _ _ .N3 _____________| |_______________________| |_________ . _ _ .N4 _________________| |_______________________| |_____ . _ _ _ _ .CLK ________| |_________| |___________| |_________| |_

with the result that your circuit (assuming edge rates equal to those of the comparator) is generating five times as much noise as the output of the comparator, FIN.

--
>>
>>>Measuring the ugliness of your designs is like evaluating 0/0. 
>>
>>---
>>Fred\'s designs aren\'t ugly, they\'re just panoramic, and they work.
>
>Fred doesn\'t design things. He\'s said so. He sure didn\'t take a shot
>at this problem. Mostly what Fred does is criticize designs for
>emotional reasons, and look up a lot of old papers and cite them.
>
>
>>And, evaluating 0/0 to the limit leads to:
>>
>>     0
>>    --- = 1
>>     0
>>
>>which would seem to lend credence to his designs as being valid, \'1\'
>>being assumed to be true.
>
>He doesn\'t design.
Reply to
John Fields

And includes the unobtainium "Delay" box, whose output splits into two timing-critical paths, always an alarm in async logic. Finish the design and we'll see.

Blogs doesn't design electronics. Surprisingly few S.E.D posters actually do.

John

Reply to
John Larkin

Alzheimer's setting in, John? Posted many moons ago...

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Nope. Switches "sex" out in the middle of no activity. Talk about not understanding... you have NO CLUE how my design works.

I certainly do. I have the income and repeat customers to prove it.

I thought you did too ??

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
         America: Land of the Free, Because of the Brave
Reply to
Jim Thompson

Do you know how much logic is on your PCs motherboard? Or in your keyboard, or your mouse? Do you think the designers avoided adding 4 gates because they would make "hash"?

When you design logic, do you actually avoid running signals through gates because gates cause emi?

I offered a circuit that has two cans and does everything the OP specified, and is timing-hazard free. And you're complaining that I'm using a quad xor gate to process his signal, and that's bad because it's an emi hazard. Preposterous.

John

Reply to
John Larkin

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