qpsk project..pls help me

[farhan13]

hi..
i have a problem regarding qpsk project..
input for i & q are:

i=0.5sin(2pi10t)+sin(2pi20t)
q=0.7sin(2pi15t)+0.3sin(2pi25t)

sampling freq=500
carrier freq=21000

how do i simulate this using matlab?do u have any code example?

below are the diagram for my project

 

[farhan13]

pls help me..anybody..i haven't found a way to do matlab coding

 

[Aya2002]

clc;
clear all;close all;
disp('M-Array PSK Modulation')
%create a random digital message
M=input ('M= '); %alphabet size
x=randint(input('Number of binary bit stream = '),1,M);
%%

nsample=40; %oversampling rate.
%%

%%
%use M-PSK modulation to produce y
y=modulate(modem.pskmod(M),x);
L=length
%%
%follow with rectangular pulse shaping.
ypulse=rectpulse(y,nsample);

%%
% Power Spectral Density plot
pwelch(ypulse)
%%
%%transmit signal through an AWGN Channel
ynoisy=awgn(ypulse,input('SNR in dB = '),'measured');

%%
%Create scattet plot from noisy data
scatterplot(ynoisy),grid;
%%
%Downsample at the reciever.
ydownsample=intdump(ynoisy,nsample);
%%
%Demodulate ynoisy to recover the message.
z=demodulate(modem.pskdemod(M),ydownsample);
figure;
subplot(2,1,1);
stem(x(1:10),'filled'),grid;
subplot(2,1,2);
stem(z(1:10),'filled'),grid;
%%
%Check symbole erroe rate.
[num ty]=symerr(x,z)

 

[farhan13]

sorry..still don't understand..
how do i put both input for i & q in the code?

btw, i need qpsk output

 

[farhan13]

i=0.5sin(2pi10t)+sin(2pi20t)
q=0.7sin(2pi15t)+0.3sin(2pi25t)

sampling freq=500
carrier freq=21000

how do i change both i&q input to digital?pls help..

 

[Communications_Engineer]

If you for e.g. Mod contains QPSK modulated symbols, this is how you can transmit it on I and Q components

real(Mod)*I + j* imag(Mod)*Q