matlab experiments eg

8/6/2019 Matlab experiments eg

1/26

butterworth digital low-pass

lc;

lear all;

p= input ('Enter the passband ripple : ');

s= input ('Enter the stopband ripple : ');

p= input ('Enter the passband frequency : ');

s= input ('Enter the stopband frequency : ');

s= input ('Enter the sampling frequency : ');

Converting frequency into radians

1 = 2*wp/fs;

2 = 2*ws/fs;

Cutoff frequency and order of the filter

n,wn]= buttord (w1,w2,rp,rs);

system function of the filter

b,a]=butter(n,wn);

= 0:0.01:pi;

h,om]= freqz(b,a,w);%

=20*log10(abs(h));

n=angle(h);

ubplot(2,1,1);

lot(om/pi,m);label('Gain in dB'),xlabel('Normalised frequency'),title('MAGNITUDE PLOT');

ubplot(2,1,2);

lot(om/pi,an);

label('Normalised frequency'),ylabel('Phase in radians'),title('PHASE PLOT');

ample output

nter the passband ripple : .15

nter the stopband ripple : 60nter the passband frequency : 1500

nter the stopband frequency : 3000nter the sampling frequency : 7000


2/26


3/26

BUTTERWORTH DIGITAL HIGH-PASS

lc;

lear all;




s= input ('Enter the stopband frequency : ');s= input ('Enter the sampling frequency : ');


1 = 2*wp/fs;

2 = 2*ws/fs;


n,wn]= buttord (w1,w2,rp,rs);


b,a]=butter(n,wn,'high');

= 0:0.01:pi;

h,om]= freqz(b,a,w,'whole');=20*log10(abs(h));

n=angle(h);

ubplot(2,1,1);

lot(om/pi,m);

label('Gain in dB'),xlabel('Normalised frequency'),title('MAGNITUDE PLOT');

ubplot(2,1,2);

lot(om/pi,an);

label('Normalised frequency'),ylabel('phase in radians'),title('PHASE PLOT');

ample output


nter the stopband ripple : 60

nter the passband frequency : 1500nter the stopband frequency : 3000

nter the sampling frequency : 7000


4/26


5/26

BUTTERWORTH bandPASS

lc;

lear all;

lose all;







1 = 2*wp/fs;2 = 2*ws/fs;


n]= buttord (w1,w2,rp,rs);

n=[w1 w2];


b,a]=butter(n,wn,'bandpass');

= 0:0.01:pi;

h,om]= freqz(b,a,w);

=20*log10(abs(h));

n=angle(h);

ubplot(2,1,1);lot(om/pi,m);


ubplot(2,1,2);

lot(om/pi,an);




nter the passband frequency : 1500

nter the stopband frequency : 2000



6/26


7/26

BUTTERWORTH bandstop

lc;

lear all;

lose all;







1 = 2*wp/fs;2 = 2*ws/fs;


n]= buttord (w1,w2,rp,rs);

n=[w1 w2];


b,a]=butter(n,wn,'stop');

= 0:0.01:pi;


=20*log10(abs(h));

n=angle(h);



ubplot(2,1,2);

lot(om/pi,an);




nter the passband frequency : 1100

nter the stopband frequency : 2200



8/26


9/26

CHEBYSHEV LOWPASS FILTER

lear all;

p= input ('Enter the passband ripple :');

s= input ('Enter the stopband ripple :');

p= input ('Enter the passband frequency:');

s= input ('Enter the stopband frequency:');

s= input ('Enter the sampling frequency:');

frequency in radians

1 = 2*wp/fs;

2 = 2*ws/fs;

order and cutoff frequency of the filtern,wn]= cheb1ord (w1,w2,rp,rs);


b,a]= cheby1(n,rp,wn);

= 0:0.01:pi;


=20*log10(abs(h));

n=angle(h);

ubplot(2,1,1);

lot(om/pi,m);


ubplot(2,1,2);

lot(om/pi,an);

label('Normalised frequency'),ylabel('Phase in radians'),title('PHASE PLOT');

ample output

nter the passband ripple :.2

nter the stopband ripple :45nter the passband frequency:1300

nter the stopband frequency:1500

nter the sampling frequency:10000


10/26


11/26

CHEBYSHEV HIGHPASS FILTER

lc;

lear all;







1 = 2*wp/fs;

2 = 2*ws/fs;

order and cutoff frequency of the filter

n,wn]= cheb1ord (w1,w2,rp,rs);


b,a]= cheby1(n,rp,wn,'high');

= 0:0.01/pi:pi;


=20*log10(abs(h));

n=angle(h);

ubplot(2,1,1);


ubplot(2,1,2);

lot(om/pi,an);


ample output


nter the stopband ripple :60

nter the passband frequency:1500nter the stopband frequency:2000



12/26


13/26

CHEBYSHEV BANDPASS FILTER

lc;

lear all;







1 = 2*wp/fs;

2 = 2*ws/fs;


n]= cheb1ord (w1,w2,rp,rs);

n=[w1 w2];


b,a]= cheby1(n,rp,wn,'bandpass');

= 0:0.01:pi;


=20*log10(abs(h));

n=angle(h);



ubplot(2,1,2);

lot(om/pi,an);







14/26


15/26

CHEBYSHEV BANDstop FILTER

lc;

lear all;







1 = 2*wp/fs;

2 = 2*ws/fs;



n=[w1 w2];


b,a]= cheby1(n,rp,wn,'stop');

= 0:0.01:pi;


=20*log10(abs(h));

n=angle(h);



ubplot(2,1,2);

lot(om/pi,an);




nter the passband frequency:2500




16/26


17/26

CHEBYSHEV type2 LOWPASS FILTER

lc;

lear all;







1 = 2*wp/fs;

2 = 2*ws/fs;




b,a]= cheby2(n,rs,wn);

= 0:0.01:pi;


=20*log10(abs(h));

n=angle(h);

ubplot(2,1,1);

lot(om/pi,m);


ubplot(2,1,2);

lot(om/pi,an);


ample output

nter the passband ripple :.15nter the stopband ripple :35

nter the passband frequency:1500




18/26


19/26

CHEBYSHEV type2 highpass FILTER

lc;

lear all;







1 = 2*wp/fs;

2 = 2*ws/fs;




b,a]= cheby2(n,rs,wn,'high');

= 0:0.01:pi;


=20*log10(abs(h));

n=angle(h);

ubplot(2,1,1);

lot(om/pi,m);


ubplot(2,1,2);

lot(om/pi,an);







20/26


21/26


22/26


23/26

CHEBYSHEV type2 bandstop FILTER

lc;

lear all;







1 = 2*wp/fs;

2 = 2*ws/fs;



n=[w1 w2];


b,a]= cheby2(n,rs,wn,'stop');

= 0:0.01:pi;


=20*log10(abs(h));

n=angle(h);

ubplot(2,1,1);


ubplot(2,1,2);

lot(om/pi,an);







24/26

IR FILTER 1

To design a 25-tap lowpass filter with cutoff frequency

.5pi using hanning and hamming window

lear all;

c=.5*pi;

=25;

lpha=(N-1)/2;

ps=.001;

=0:1:N-1;

d=(sin(wc*(n-alpha+eps)))./(pi*(n-alpha+eps));r=hann(N); %hanning window sequence

n=hd'.*wr; % filter coefficients

=0:0.01:pi;

=freqz(hn,1,w);

lot(w/pi,abs(h),'red');

old on

b=hamming(N); %hamming window sequence

n=hd'.*wb; % filter coefficients

=0:0.01:pi;

=freqz(hn,1,w);

lot(w/pi,abs(h));

label('Magnitude');

label('Normalised frequency');old off


25/26

IR FILTER 2

To design FIR LPF using rectangular & blackmann window

lc;

lear all;

c=.5*pi; %cutoff frequency

=25;

=fir1(N,wc/pi,rectwin(N+1));

=0:0.01:pi;

=freqz(b,1,w);

lot(w/pi,abs(h),'red');

old on

=fir1(N,wc/pi,blackman(N+1));

=0:0.01:pi;

=freqz(b,1,w);

lot(w/pi,abs(h));

label('Magnitude');

label('Normalised frequency');

old off


26/26

requency Response of the first order system

lc;

lear all;

=1;

=[1 0.36]

= 0:0.1:pi;

h w]=freqs(b,a,w);

ubplot(2,1,1);

lot(w/pi,abs(h));

label('w');label('|H(w)|');

itle('Frequency Response-Magnitude Function');

ubplot(2,1,2);

lot(w/pi,angle(h));

label('w');

label('angle|H(w)|');

itle('Frequency Response-Phase Function');

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