From: "John Jardine"
Subject: Re: circuit wanted-SQUARE PULSE GENERATOR
Date: Tue, 26 Nov 2002 18:31:50 -0000
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NNTP-Posting-Date: 26 Nov 2002 18:20:03 GMT
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Jim Thompson wrote in message
> On Tue, 26 Nov 2002 17:37:26 -0000,
> "John Jardine" ,
> In Newsgroup: sci.electronics.design,
> Article: ,
> 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'
> |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.
> ...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 | |
> | Jim-T@analog_innovations.com Fax:(480)460-2142 | Brass Rat |
> | http://www.analog-innovations.com | 1962 |
> For proper E-mail replies SWAP "-" and "_"
> I love to cook with wine. Sometimes I even put it in the food.
Jim, You've just made my day ;-)
First used in a 1MHz function gen I was playing with. Used LM301's and a
I/2I triangle generator. Never pursued it as it disfigured my neat triangle.