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11-30-1999
03:00 AM

11-30-1999
03:00 AM

Simple pulse and Symbolic F.T error

I would appreciate any help with the following error using Mathcad7 and the symbolic fourier transform of a simple pulse function.

Please see the attached file

Craig

Please see the attached file

Craig

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11-30-1999
03:00 AM

11-30-1999
03:00 AM

Simple pulse and Symbolic F.T error

Mathcad seems to have different notations for the Dirac delta function floating around all at once - I don't know why! - but it has something to do with the Maple symbolic engine. Delta(n+1,x) denotes the derivative of Delta(n,x). See the attached Mathcad 7 quicksheet. I'm afraid I don't understand your other question. Sorry.

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11-30-1999
03:00 AM

11-30-1999
03:00 AM

Simple pulse and Symbolic F.T error

Bonnie,

Thanks for the example. I ran across that in my searching but it still left me a little confused.

mathcad returns dirac(1,w) in the

fourier transform but it also says that it is undefined. How would I define this dirac derivative (?) function inside of mathcad?

I guess i don't really understand what mathcad is returning as a result. What i did was put an expression in mathcad so the error would disappear but this leaves a "blip" in my F(w) graph at w=0 ---- F(0)=1 in the graph and not the correct value of 1.5

Thx for your help,

Craig

Thanks for the example. I ran across that in my searching but it still left me a little confused.

mathcad returns dirac(1,w) in the

fourier transform but it also says that it is undefined. How would I define this dirac derivative (?) function inside of mathcad?

I guess i don't really understand what mathcad is returning as a result. What i did was put an expression in mathcad so the error would disappear but this leaves a "blip" in my F(w) graph at w=0 ---- F(0)=1 in the graph and not the correct value of 1.5

Thx for your help,

Craig

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12-01-1999
03:00 AM

12-01-1999
03:00 AM

Simple pulse and Symbolic F.T error

Dirac delta and its derivatives are not "functions" in the ordinary sense and true numerical use of these is impossible.

I'm afraid I don't understand your worksheet well enough to know what "blip" you're talking about. Experience has taught me to be careful when using and interpreting Maple symbolic output within Mathcad worksheets. It's quite possible that there is a third-party bug somewhere. I would find a book on Fourier transforms (or whatever) and understand what the answer should be. Then compare. If you see an obvious discrepancy, then e-mail MathSoft Tech Support. Right now, I'm unable to see what the discrepancy is and so can't help.

Sorry...

I'm afraid I don't understand your worksheet well enough to know what "blip" you're talking about. Experience has taught me to be careful when using and interpreting Maple symbolic output within Mathcad worksheets. It's quite possible that there is a third-party bug somewhere. I would find a book on Fourier transforms (or whatever) and understand what the answer should be. Then compare. If you see an obvious discrepancy, then e-mail MathSoft Tech Support. Right now, I'm unable to see what the discrepancy is and so can't help.

Sorry...