# Laplace & Fourier transforms

Discussion in 'Electronics Resources' started by elecstudent, Dec 11, 2010.

1. ### elecstudent Thread Starter New Member

Nov 11, 2010
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I hope I'm posting this in the right area..

Hi I was wondering if anyone can guide me to a suitable comprehensive source, to enable me to understand Laplace & Fourier transforms as I can't visualise these/abstract or other.

The maths is ok (for now) I'm more concerned to understand what these transforms are for, and best way to visualise them.

Thanks

2. ### tyblu Active Member

Nov 29, 2010
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Visualizing their applications likely won't come until you study communications and filters, looking at Bode plots and the like. The WikiP descriptions aren't bad.

3. ### elecstudent Thread Starter New Member

Nov 11, 2010
26
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Can anyone else add something more substantial.

regards

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6. ### count_volta Active Member

Feb 4, 2009
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From my experience I can tell you that,

Laplace Transforms are useful for solving differential equations easily. Getting the transfer function easily. Poles and zeros for control systems. Also, get the Laplace Transform and plug in S=jw and you have the Fourier Transform.

Fourier Transforms are useful for: Everything that has to do with Radio. Filters. Finding out what frequencies your signal is composed of. Filtering out frequencies you don't need. AM and FM. And many other things.

Try this.

Listen to the Fourier transform. You need to be able to visualize it. A square wave is made up of many sine waves added together. So its composed of many frequencies or harmonics because they are odd multiples of the fundamental frequency. A pure sine wave has only the fundamental frequency. The Fourier series says that every periodic signal is made of sine waves. The Fourier Transform is a continuous version of the Fourier Series.

Last edited: Dec 18, 2010
7. ### Prof78 New Member

Dec 24, 2010
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See the book An Analog Electronics Companion (Cambridge University Press ISBN 9780521687805) for a treatment of both Fourier and Laplace transforms and their use in electronics. It is assumed that your maths is capable as you state. Included is a copy of the student version of PSpice, which allows a demonstration of the Fourier components of a wave. The book is not suitable for neophytes.

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