From: Jim Thompson
Subject: Re: circuit wanted-SQUARE PULSE GENERATOR
References: <1038144646.265208@athprx02> <email@example.com> <firstname.lastname@example.org> <email@example.com>
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Date: Tue, 26 Nov 2002 17:42:16 GMT
NNTP-Posting-Date: Tue, 26 Nov 2002 12:42:16 EST
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On Tue, 26 Nov 2002 17:37:26 -0000,
"John Jardine" ,
In Newsgroup: sci.electronics.design,
Entitled: "Re: circuit wanted-SQUARE PULSE GENERATOR",
Wrote the following:
|Jim Thompson wrote in message
|> Here's a question for all you lurkers:
|> Delay in the comparators (in a 555 or otherwise) affect the linearity
|> of the control curve, particularly at high frequencies (I've built
|> these at frequencies as high as 50MHz).
|> Can anyone here mathematically describe the effect as a function of
|> delay and operating frequency?
|> And then offer a solution?
|> (I can ;-)
|> ...Jim Thompson
|Treading in *deep* water here but the solution is to stick a resistor in
|series with that timing cap'. The effect is to add sufficient 'pre-act' to
|balance the accruing switch losses
Congratulations, John, that *is* the solution. I didn't expect such a
quick answer !-)
I can't remember the application now, but I first came upon this while
doing a PLL at 20MHz back in the days of TTL.
| 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 | |
| Jim-T@analog_innovations.com Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
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