PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

Analog and Digital Filters 645

The transfer function is given by

H(s)




1

sss^32221

(6.4)

Equating the coeffi cients of Equation 6.3 with the coeffi cients of Equation 6.4 the follow-

ing relations are obtained:

L 1 L 2 C = 1

L 1 C = 2

L 1 + L 2 = 2

Then solving for L 1 , L 2 , and C the following is obtained:

L 1 = 3/2 H, L 2 = 1/2 H, and C = 4/3 F

Then the normalized LPF at the component level is shown in Figure 6.70.

Frequency and magnitude scaling results in

new-R 0 = R (^) R 0 = (^1) 100 = 100 Ω
L
LR
(^011044)
2
10
3 100
210
310
2




15
** 

• 
  


• mH
  L
  LR
  02 2010442
  100
  210
  
  
  
  
  * 0 5 10 5


• 
  

. m* H

C

C

(^0) wRc 0 42
(^46)
3
1
10 10
4
3




10  1 33

• 
  


• 
  


• 
  

  *. F
  FIGURE 6.69
  Normalized fi lter’s plot of Example 6.17.
  0 200
  150
  100
  50
   50
   100
   150
   200
   4  2024
  0
   5
   10
  gain in db
  Phase in degrees
  w in rad/sec w in rad/sec
  Normalize filter/magnitude Normalize filter/phase
   15
   20
   25
   30
   4  2240