Using this table
for Z Transforms with Discrete Indices
Shortened 2-page pdf of Laplace
Transforms and Properties
Shortened 2-page pdf of Z
Transforms and Properties
All time domain functions are implicitly=0 for
t<0 (i.e. they are multiplied by unit step).
| Entry |
Laplace Domain | Time Domain (note) | Z Domain (t=kT) |
|---|---|---|---|
| unit impulse |
|
unit impulse |
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| unit step |
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(note) |
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| ramp |
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| parabola |
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| tn (n is integer) |
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|
| exponential |
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| power |
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|
| time multiplied exponential |
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| Asymptotic exponential |
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| double exponential |
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| asymptotic double exponential |
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|
| asymptotic critically damped |
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|
| differentiated critically damped |
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|
| sine |
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| cosine |
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| decaying sine |
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| decaying cosine |
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| generic decaying oscillatory |
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|
| generic decaying oscillatory (alternate) |
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|
| Z-domain generic decaying oscillatory |
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|
| Prototype Second Order System (ζ<1, underdampded) | |||
| Prototype 2nd order lowpass step response |
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| Prototype 2nd order lowpass impulse response |
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| Prototype 2nd order bandpass impulse response |
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Commonly the "time domain" function is given in terms of a discrete index, k, rather than time. This is easily accommodated by the table. For example if you are given a function:

Since t=kT, simply replace k in the function definition by k=t/T. So, in this case,

and we can use the table entry for the ramp

The answer is then easily obtained
© Copyright 2005-2013 Erik Cheever This page may be freely used for educational purposes.
Erik Cheever Department of Engineering Swarthmore College