# Converting 8-PSK to PI/4 QPSK

Discussion in 'The Projects Forum' started by jayo57, Aug 2, 2013.

1. ### jayo57 Thread Starter New Member

Apr 21, 2013
4
0
Hi,

I'm trying to convert the following scilab code which is for 8-PSK modulation into PI/4 QPSK. If anyone could show me how to do this, or point me in the direction of some useful documentation, it would be greatly appreciated.

interpx = 64; bits = 4000; x=sin(22.5); y=cos(22.5); Alpha=[-x,-y,-x,-y,x,y,x,y] Beta=[-y,-x,y,x,-y,-x,y,x] data = round(7*rand(1, bits)); dataA = zeros(1, bits*interpx); dataB = zeros(1, bits*interpx); data1=zeros(1, bits*interpx); for m = 1:interpx, data1(m:interpx:bits*interpx) = data; end disp(data) for n= 1:bits*interpx myvar = data1(n) select myvar case 1 then dataA(n) = -x; dataB(n) = -y; case 2 then dataA(n) = -y; dataB(n) = -x; case 3 then dataA(n) = -x; dataB(n) = y; case 4 then dataA(n) = -y; dataB(n) = x; case 5 then dataA(n) = x; dataB(n) = -y; case 6 then dataA(n) = y; dataB(n) = -x; case 7 then dataA(n) = x; dataB(n) = y; case 8 then dataA(n) = y; dataB(n) = x; end end t=0:1/2:(bits*interpx/2)-1/2; carrier1 = sin(t); carrier2 = cos(t); wave1= (carrier1.*dataA);//multiple carrier.*data2 wave2= (carrier2.*dataB);//multiple carrier.*data2 eight_psk=(wave1+wave2); scf(0) plot(eight_psk);

2. ### jayo57 Thread Starter New Member

Apr 21, 2013
4
0
Hi Guys,

I figured out the solution. Thanks anyway.