(Invertible Systems)
(Time Variant:)
 
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== Invertible Systems ==
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== Time Invariant Systems ==
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A system is invertible if distinct inputs yield distinct outputs.
 
 
Invertible System:
 
 
y(t) = <math>\frac{3*x(t) + 8}{1}</math>
 
 
x(t) = <math>\frac{y(t) - 8}{3}</math>
 
 
x(t) -> |Sys 1| -> y(t) -> |Sys 2| -> x(t)
 
 
The two equations are inverses of each other.
 
 
Noninvertible System:
 
 
y(t) = <math>t^4</math>
 
 
   
 
   
  x(t) = <math>t</math>    ->     |Sys|     ->     y(t) = <math>t^4</math>
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  A system is time invariant if for any function x(t), a time shift of the function x(t-t0),
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is commutative with the other effects of the system.
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x(t)  ->   |Sys|   ->   |time delay by t0|  -> a(t)
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x(t)  ->   |time delay by t0|  ->  |Sys|  -> a(t)
 
    
 
    
  x(t) = <math>-t</math>    ->    |Sys|    ->    y(t) = <math>t^4</math>
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  If this resulting function a(t) is the same for both cascades then the system is time invariant.</nowiki>
  
  The System is not invertible because for a given set of inputs you cannot differentiate which of the output will result.
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== Time Variant Systems: ==
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A system is time variant if the results of the cascaded systems are not the same.

Latest revision as of 12:46, 16 September 2008

Time Invariant Systems



A system is time invariant if for any function x(t), a time shift of the function x(t-t0),
is commutative with the other effects of the system.

x(t)   ->   |Sys|   ->   |time delay by t0|   -> a(t)
  
x(t)   ->   |time delay by t0|   ->   |Sys|   -> a(t)
 
If this resulting function a(t) is the same for both cascades then the system is time invariant.</nowiki>

Time Variant Systems:

A system is time variant if the results of the cascaded systems are not the same.

Alumni Liaison

Abstract algebra continues the conceptual developments of linear algebra, on an even grander scale.

Dr. Paul Garrett