PRACTICAL MATLAB® FOR ENGINEERS PRACTICAL MATLAB

Analog and Digital Filters 605

ANALYTICAL Solution

Part (a)

Hw

Vw

Vw

R

jwC

R

jw

jw

RC

o

i

()

()

()

*

*

*





11

Part (b)

Hw

w

w

RC

()

*

(^2) 
1 2




∠Hw()^2 tan w R C^ ^ ^

()^1 ( )
MATLAB Solution
% Script File: HP filter analysis
% RC-High Pass Filter Analysis
R=1e3/(2pi);
C=.1e-6;
a = 1/(RC);
w = -5a:10000:5a;
num = [1 0];
den = [1 a];
Hhp = freqs(num,den,w);
figure(1);
subplot(2,1,1);
plot(w/(2pi),abs(Hhp));
ylabel(‘magnitude’);
xlabel(‘frequency in Hrz’);
title(‘Magnitude of H(f) vs. frequency’);
subplot(2,1,2);
plot(w/(2pi),angle(Hhp)180/pi);
xlabel(‘frequency in Hrz’);
ylabel(‘phase in degrees’);
title(‘Phase of H(f) vs. frequency’);
figure(2)
db=20.log(abs(Hhp));
FIGURE 6.31
Circuit diagram of Example 6.2.
R
C
Vi(w) Vo(w)