QUADRATURE PHASE SHIFT KEYING (QPSK)

PROGRAM:
clc;
clf;
clear;
bs = input('Enter the input bit sequence :');
f = input('Enter the modulating signal frequency :');
p = input('Enter the modulating signals phase differences[p2,p3,p4] :');
a = input('Enter the modulating signal amplitude :');
c = 0;
d = 0;
l = length(bs);
if  (mod(l,2) ~= 0)
    bs = [bs,0];
end

% code for generating binary signal
for i = 1:l
    t1 = (c:0.01:c+1);
    x = bs(i) * ones(length(t1),1);
    subplot(2,1,1);
    plot(t1,x);
    axis([0 l -1 2]);
    xlabel('time ->');
    ylabel('amplitude ->');
    title('binary signal');
    hold on
    c=c+1;
end

% code for generating qpsk signal
for i=1:2:l
    t=(d:0.01:d+2);
    if (bs(i)==0 && bs(i+1)==0)
        b = sin(2 * pi * f * t);
    elseif (bs(i)==0 && bs(i+1)==1)
        b = sin(2 * pi * f * t + p(1));
    elseif (bs(i)==1 && bs(i+1)==0)
        b = sin(2 * pi * f * t + p(2));
    elseif (bs(i)==1 && bs(i+1)==1)
        b = sin(2 * pi * f * t + p(3));
    end
    subplot(2,1,2);
    plot(t,b);
    xlabel('time ->');
    ylabel('amplitude ->');
    title('qpsk signal');
    hold on
    d=d+2;
end

SAMPLE OUTPUT:
Enter the input bit sequence :[0 0 0 1 1 0 1 1]
Enter the modulating signal frequency :2
Enter the modulating signals phase differences[p2,p3,p4] :[90 180 270]
Enter the modulating signal amplitude :3

PLOT:

QUADRATURE FREQUENCY SHIFT KEYING (QFSK)

PROGRAM:
clc;
clf;
clear;
bs = input('Enter the input bit sequence :');
f = input('Enter the modulating signal frequencies[f1 f2 f3 f4] :');
a = input('Enter the modulating signal amplitude :');
c = 0;
d = 0;
l = length(bs);
if  (mod(l,2) ~= 0)
    bs = [bs,0];
end

% code for generating binary signal
for i = 1:l
    t1 = (c:0.01:c+1);
    x = bs(i) * ones(length(t1),1);
    subplot(2,1,1);
    plot(t1,x);
    axis([0 l -1 2]);
    xlabel('time ->');
    ylabel('amplitude ->');
    title('binary signal');
    hold on
    c=c+1;
end

% code for generating qfsk signal
for i=1:2:l
    t=(d:0.01:d+2);
    if (bs(i)==0 && bs(i+1)==0)
        b = sin(2 * pi * f(1) * t);
    elseif (bs(i)==0 && bs(i+1)==1)
        b = sin(2 * pi * f(2) * t);
    elseif (bs(i)==1 && bs(i+1)==0)
        b = sin(2 * pi * f(3) * t);
    elseif (bs(i)==1 && bs(i+1)==1)
        b = sin(2 * pi * f(4) * t);
    end
    subplot(2,1,2);
    plot(t,b);
    xlabel('time ->');
    ylabel('amplitude ->');
    title('qfsk signal');
    hold on
    d=d+2;
end

SAMPLE OUTPUT:
Enter the input bit sequence :[0 0 0 1 1 0 1 1]
Enter the modulating signal frequencies[f1 f2 f3 f4] :[1 8 16 32]
Enter the modulating signal amplitude :2

PLOT:

BINARY PHASE SHIFT KEYING (BPSK)

PROGRAM:
clc;
clf;
clear;
bs = input('Enter the input bit sequence :');
f = input('Enter the modulating signal frequency :');
p = input('Enter the modulating signal2 phase difference :');
a = input('Enter the modulating signal amplitude :');
c = 0;
d = 0;
l = length(bs);

% code for generating binary signal
for i = 1:l
    t1 = (c:0.01:c+1);
    x = bs(i) * ones(length(t1),1);
    subplot(2,1,1);
    plot(t1,x);
    axis([0 l -1 2]);
    xlabel('time ->');
    ylabel('amplitude ->');
    title('binary signal');
    hold on
    c=c+1;
end

% code for generating bpsk signal
for i = 1:l
    t=(d:0.01:d+1);
    if (bs(i) == 0)
        b = sin(2 * pi * f * t);
    else
        b = sin(2 * pi * f * t + p);
    end
    subplot(2,1,2);
    plot(t,b);
    xlabel('time ->');
    ylabel('amplitude ->');
    title('bpsk signal');
    hold on
    d=d+1;
end

SAMPLE OUTPUT:
Enter the input bit sequence :[0 1 0 1 1]
Enter the modulating signal frequency :4
Enter the modulating signal2 phase difference :180
Enter the modulating signal amplitude :2

PLOT:

BINARY FREQUENCY SHIFT KEYING (BFSK)

PROGRAM:
clc;
clf;
clear;
bs = input('Enter the input bit sequence :');
f = input('Enter the modulating signal frequencies[f1 f2] :');
a = input('Enter the modulating signal amplitude :');
c = 0;
d = 0;
l = length(bs);

% code for generating binary signal
for i = 1:l
    t1 = (c:0.01:c+1);
    x = bs(i) * ones(length(t1),1);
    subplot(2,1,1);
    plot(t1,x);
    axis([0 l -1 2]);
    xlabel('time ->');
    ylabel('amplitude ->');
    title('binary signal');
    hold on
    c=c+1;
end

% code for generating bfsk signal
for i = 1:l 
    t=(d:0.01:d+1);
    if (bs(i) == 0)
        b = sin(2 * pi * f(1) * t);
    else
        b = sin(2 * pi * f(2) * t);
    end
    subplot(2,1,2);
    plot(t,b);
    xlabel('time ->');
    ylabel('amplitude ->');
    title('bfsk signal');
    hold on
    d=d+1;
end

SAMPLE OUTPUT:
Enter the input bit sequence :[0 1 0 1 1]
Enter the modulating signal frequencies[f1 f2] :[4 15]
Enter the modulating signal amplitude :3

PLOT:

BINARY AMPLITUDE SHIFT KEYING (BASK)

PROGRAM:
clc;
clf;
clear;
bs = input('Enter the input bit sequence :');
f = input('Enter the modulating signal frequency(Hz) :');
a = input('Enter the modulating signal amplitude :');
c = 0;
d = 0;
l = length(bs);

% code for generating binary signal
for i = 1:l   
    t1 = (c:0.01:c+1);
    x = bs(i) * ones(length(t1),1);
    subplot(3,1,1);
    plot(t1,x);
    axis([0 l -1 2]);
    xlabel('time (s) ->');
    ylabel('amplitude (v) ->');
    title('BINARY SIGNAL');
    hold on
    c=c+1;
end

% code for generating modulating signal
mt = (0:0.01:l);
ms = a * sin(2 * pi * f* mt);
subplot(3,1,2);
plot(mt,ms);
xlabel('time (s) ->');
ylabel('amplitude (v) ->');
title('MODULATING SIGNAL');

% code for generating bask signal
for i = 1:l
    t2 = (d:0.01:d+1);
    y = bs(i) * a * sin(2*pi*f*t2);
    subplot(3,1,3);
    plot(t2,y);
    xlabel('time (s) ->');
    ylabel('amplitude (v) ->');
    title('BASK SIGNAL');
    hold on
    d=d+1;
end 

SAMPLE OUTPUT:
Enter the input bit sequence :[0 1 0 1 1]
Enter the modulating signal frequency(Hz) :4
Enter the modulating signal amplitude :2

PLOT: