PSK:
Psk is the one of the digital modulation technique. in this technique phase of the carrier signal is varied according to the message signal. In case of binary PSK we use two phases 0 and 180. To transmit the bit one we transmit the carrier signal as it is with out the phase change. To transmit the bit zero we transmit the carrier wave with phase change of 180 with respect to the original carrier wave. the power consumed by this technique is more than the ASK because this technique uses carrier to transmit the bit zero also.similar to any digital modulation technique PSK also uses the finite number of distinct signals to represent the digital data. incase of bpsk i.e bipolar phase
shift keying we use two distinct signals which are in phase difference of 180 degrees. we can implement the PSK in two methods one is in the form of differential phase shift keying in this the phase of the carrier is changed with respect to the previous bit. in other case the phase is changed with the instantaneous message signal which is in digital nature.
a=input('enter the sequence')
k=length(a)
t=[0.01:0.01:k]
f=7
for i=1:1:k
shift keying we use two distinct signals which are in phase difference of 180 degrees. we can implement the PSK in two methods one is in the form of differential phase shift keying in this the phase of the carrier is changed with respect to the previous bit. in other case the phase is changed with the instantaneous message signal which is in digital nature.
a=input('enter the sequence')
k=length(a)
t=[0.01:0.01:k]
f=7
for i=1:1:k
if a(i)==1
a(i)=1
else
a(i)=0
end
end
for i=1:1:k
m((i-1)*100+1:i*100)=a(i)
end
subplot(211)
plot(m)
xlabel('time')
ylabel('amplitude')
title('message signal')
wt=2*pi*f*t
c=sin(wt+(1-m).*pi)
subplot(212)
plot(c)
xlabel('time')
ylabel('amplitude')
title('phase shift keying')
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