Re: Help QPSK
MATLAB provides an excellent Help, just do a search there and most of your answers will be there!
len = 10000; % Number of symbols
M = 4; % Size of alphabet
msg = randint(len,1,M); % Original signal
% Modulate using PSK
txpsk = pskmod(msg,M);
nsamp = 11; % Oversampling rate
%% Filter Definition
% Define filter-related parameters.
filtorder = 40; % Filter order
delay = filtorder/(nsamp*2); % Group delay (# of input samples)
rolloff = 0.25; % Rolloff factor of filter
% Create a square root raised cosine filter.
rrcfilter = rcosine(1,nsamp,'fir/sqrt',rolloff,delay);
% Upsample and apply square root raised cosine filter.
ytx = rcosflt(txpsk,1,nsamp,'filter',rrcfilter);