(New page: Find if each system is stable and causal. '''A''' h(t) = <math> e^{-4t} u(t-2) u(t-2) = 1 for t >= 2 making h(t) = 0 for t < 2. The system is causal. <math>\int_{-\infty}^\infty e^{-4...)
 
 
(One intermediate revision by one other user not shown)
Line 3: Line 3:
 
'''A'''
 
'''A'''
  
h(t) = <math> e^{-4t} u(t-2)
+
h(t) = <math>e^{-4t} u(t-2)</math>
  
 
u(t-2) = 1 for t >= 2 making h(t) = 0 for t < 2.  The system is causal.
 
u(t-2) = 1 for t >= 2 making h(t) = 0 for t < 2.  The system is causal.
Line 25: Line 25:
 
h(t) = <math>e^{-6|t|}</math>
 
h(t) = <math>e^{-6|t|}</math>
  
Since h(t) <math>\neq</math> = for t < 0 so the system is not causal.
+
Since h(t) <math>\neq</math> 0 for t < 0 so the system is not causal.
  
 
<math>\int_{-\infty}^\infty e^{-6|t|} = 2\int_0^\infty e^{-6t} < \infty</math>.  This system is stable.
 
<math>\int_{-\infty}^\infty e^{-6|t|} = 2\int_0^\infty e^{-6t} < \infty</math>.  This system is stable.
  
 
This system is stable but not causal.
 
This system is stable but not causal.

Latest revision as of 20:10, 22 June 2008

Find if each system is stable and causal.

A

h(t) = $ e^{-4t} u(t-2) $

u(t-2) = 1 for t >= 2 making h(t) = 0 for t < 2. The system is causal.

$ \int_{-\infty}^\infty e^{-4t} u(t-2) = /int_2^\infty e^{-4t} < \infty $. Therefore the system is stable.

This system is stable and causal.

B

h(t) = $ e^{-6t} u(3-t) $

u(3-t) = 1 for t<=3, making h(t) $ \neq $ for t < 0. The system is not causal.

$ \int_{-\infty}^\infty e^{-6t} u(3-t) = \int_{-\infty}^3 e^{-6t} = \infty $, therefore the system is not stable.

This system is neither causal or stable.

E

h(t) = $ e^{-6|t|} $

Since h(t) $ \neq $ 0 for t < 0 so the system is not causal.

$ \int_{-\infty}^\infty e^{-6|t|} = 2\int_0^\infty e^{-6t} < \infty $. This system is stable.

This system is stable but not causal.

Alumni Liaison

Basic linear algebra uncovers and clarifies very important geometry and algebra.

Dr. Paul Garrett