dspsk_mod.m

多用户检测算法直接序列扩频码 调制部分

function  y = dspsk_MOD( x, ds_parm)
pn =ds_parm.pn;
pnoffset = ds_parm.pnoffset;
Fd = ds_parm.fd;
Fc = ds_parm.fc;
Fs = ds_parm.fs;
N = ds_parm.N;
mod = ds_parm.mod;
rdcdma = ds_parm.rdcdma;

if  (Fs/Fd) ~= round(Fs/Fd)
    error('Fs/Fd is not a integer!');
end;
xlen    = length(x);
ylen    = floor(xlen*N*Fs/Fd)+1;
off     = pnoffset;
pnseries= pncode(pn,off,N,0);  % 产生扩频调制符号用的PN序列
y       = zeros(1,ylen);
for bit=0:xlen-1
    ys  = psk_SymMOD( x(bit+1),pnseries,ds_parm ); % 单符号扩频调制
    tmy = bit * (N*Fs/Fd);
    y(tmy+1:tmy+length(ys)) = ys;
    if ( rdcdma == 'R' )
        off         = off + N;  % R-CDMA要求调制的PN码连续非周期调制
        pnseries    = pncode(pn,off,N,0);  % 产生下一符号扩频调制符号用的PN序列
    end;
    % 如果不是R-CDMA，按短码处理，即off 参量不变，在下一BIT周期重复
end;

return;