(Definition)
(Example)
 
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== Example ==
 
== Example ==
 
'''Time Invariance'''
 
'''Time Invariance'''
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System: y(t)=x(t)
 
System: y(t)=x(t)
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x(t)->TD by t0 ->y(t)=x(t-t0)->System->z(t)=y(t)=x(t-t0)
 
x(t)->TD by t0 ->y(t)=x(t-t0)->System->z(t)=y(t)=x(t-t0)
  
 
x(t)->System->y(t)=x(t)->TD by t0->z(t)=y(t-t0)=x(t-t0)
 
x(t)->System->y(t)=x(t)->TD by t0->z(t)=y(t-t0)=x(t-t0)
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The output are equal. Therefore it's time invariant.
 
The output are equal. Therefore it's time invariant.
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'''Non Time Invariance'''
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System: y(t)=t*x(t)
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x(t)->TD by t0 ->y(t)=t*x(t-t0)->System->z(t)=t*y(t)=t*x(t-t0)
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x(t)->System->y(t)=t*x(t)->TD by t0->z(t)=y(t-t0)=(t-t0)*x(t-t0)
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The output are not equal. Therefore it's non time invariant

Latest revision as of 18:55, 12 September 2008

Definition

Time invariance system is if the input has certain time delay , T0, then the output should yield the same time delay T0.

Example

Time Invariance

System: y(t)=x(t)


x(t)->TD by t0 ->y(t)=x(t-t0)->System->z(t)=y(t)=x(t-t0)

x(t)->System->y(t)=x(t)->TD by t0->z(t)=y(t-t0)=x(t-t0)


The output are equal. Therefore it's time invariant.


Non Time Invariance

System: y(t)=t*x(t)


x(t)->TD by t0 ->y(t)=t*x(t-t0)->System->z(t)=t*y(t)=t*x(t-t0)

x(t)->System->y(t)=t*x(t)->TD by t0->z(t)=y(t-t0)=(t-t0)*x(t-t0)


The output are not equal. Therefore it's non time invariant

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BSEE 2004, current Ph.D. student researching signal and image processing.

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