Line 21: Line 21:
  
 
In linearity, the values are scalable and follow the rules of superposition.
 
In linearity, the values are scalable and follow the rules of superposition.
 +
 +
==An example of a non-linear system==
 +
 +
<math>y(t)=t^2*sqrt(x(t))</math>
 +
 +
x1(t)-->system--> *A =x1'(t)
 +
x2(t)-->system--> *B =x2'(t)
 +
 +
w(t)=x1'(t)+x2'(t)= <math>A*t^2*sqrt(x1(t))+B*t^2*sqrt(x2(t))</math>
 +
 +
 +
x3(t)--> *A -->system--> = x3'(t)
 +
x4(t)--> *B -->system--> = x4'(t)
 +
 +
z(t)=x3'(t) + x4'(t)= <math>t^2*sqrt(A*x1(t))+t^2*sqrt(B*x2(t))</math>
 +
 +
Since z(t) is not equal to w(t) (because one equation has root A and root B and the other just has A and B) the system is non-linear.
 +
 +
==An example of a linear system==
 +
 +
<math>y(t)=t^2*x(t)</math>
 +
 +
x1(t)-->system--> *A =x1'(t)
 +
x2(t)-->system--> *B =x2'(t)
 +
 +
w(t)=x1'(t)+x2'(t)= <math>A*t^2*x1(t)+B*t^2*x2(t)</math>
 +
 +
 +
x3(t)--> *A -->system--> = x3'(t)
 +
x4(t)--> *B -->system--> = x4'(t)
 +
 +
z(t)=x3'(t) + x4'(t)= <math>t^2*A*x1(t)+t^2*B*x2(t)</math>
 +
 +
Since z(t) is equal to w(t) the system is linear.

Latest revision as of 12:20, 10 September 2008

Linearity

Because engineers talk in symbols instead of words...the following describes linearity.

  • A/*B = multiply by any complex number
x(t) --> system --> *A 
                     |
                     + --> w(t)
                     |
y(t) --> system --> *B 

x(t) --> *A 
          |
          + --> system --> z(t)
          |
y(t) --> *B 

If z(t) == w(t) then the system is linear.

In linearity, the values are scalable and follow the rules of superposition.

An example of a non-linear system

$ y(t)=t^2*sqrt(x(t)) $

x1(t)-->system--> *A =x1'(t) x2(t)-->system--> *B =x2'(t)

w(t)=x1'(t)+x2'(t)= $ A*t^2*sqrt(x1(t))+B*t^2*sqrt(x2(t)) $


x3(t)--> *A -->system--> = x3'(t) x4(t)--> *B -->system--> = x4'(t)

z(t)=x3'(t) + x4'(t)= $ t^2*sqrt(A*x1(t))+t^2*sqrt(B*x2(t)) $

Since z(t) is not equal to w(t) (because one equation has root A and root B and the other just has A and B) the system is non-linear.

An example of a linear system

$ y(t)=t^2*x(t) $

x1(t)-->system--> *A =x1'(t) x2(t)-->system--> *B =x2'(t)

w(t)=x1'(t)+x2'(t)= $ A*t^2*x1(t)+B*t^2*x2(t) $


x3(t)--> *A -->system--> = x3'(t) x4(t)--> *B -->system--> = x4'(t)

z(t)=x3'(t) + x4'(t)= $ t^2*A*x1(t)+t^2*B*x2(t) $

Since z(t) is equal to w(t) the system is linear.

Alumni Liaison

Ph.D. 2007, working on developing cool imaging technologies for digital cameras, camera phones, and video surveillance cameras.

Buyue Zhang