MSK signal

>hi gon,
>
>i have this script written by matt wilbur (dowloaded) that returns the I
>and Q channels of MSK/GMSK modulated waveforms. hope it helps.
>
>-fahim
>
>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>function [msk_phase,gmsk_phase,xi,xq,t] =gmsk(bits,Rb,ns,BT)
>
>% 	Title:	bbgmsk.m
>%	Author: Matt Wilbur
>%	Date:   October 19, 1998.
>%
>%	Description:  This function takes a NRZ sequences of bits
>%		      (one sample per bit) and returns the phase
>%		      of an MSK and GMSK signal modulated by them.
>%
>%		      It also returns the baseband in-phase
>%		      and quadrature components of the  GMSK
>%		      signal ready for upconverting.
>%
>%		      This function accepts as arguments:
>%
>%			bits - NRZ bit stream (one sample/bit)
>%			Rb - baseband bit rate
>%			ns - number of samples per bit
>%		    BT - normalized bandwidth of Gaussian filter
>%
>%	Modified:
>
>% Set up some timing variables
>
>	Tb = 1/Rb;
>	fs = ns*Rb;
>	Ts = 1/fs;
>
>% Extend the number of bits by one to make the convolution below
>% work out nicely
>
>	numbits = max(size(bits));
>	bits(numbits+1) = bits(numbits);
>
>% Generate the msk phase first
>
>	bup = upfirdn(bits,ones(ns,1),ns,1);
>	bscale = bup * pi/2/ns;
>	bscale(1) = 0;
>	msk = cumsum(bscale);
>
>% Get the Gaussian impulse response
>
>	% 3-dB BW of filter
>	
>	Bb = BT / Tb;
>
>	% Time scale for filter --- 6 Bit periods to be safe
>	
>	t = -3*Tb:Ts:3*Tb;	
>
>	% Analog impulse from formulae
>	
>	h_a = sqrt(2*pi/log(2))*Bb*exp(-2*pi^2*Bb^2*t.^2/log(2));
>
>	% Digital impulse from impulse-response matching
>
>	h_d = Ts*h_a;
>
>% Get the GMSK phase --- a few delay tricks so beware of shifting
>% indices
>
>	[temp,delay] = max(h_d);
>	
>	y = conv(h_d, msk);
>	upper_index = ns*numbits-1;
>	gmsk_phase = rem(y(delay:upper_index + delay), 2*pi);
>	msk_phase = msk(1:upper_index+1);
>
>	t = 0:ns*numbits-1;
>	t = t/fs;
>	xi = cos(gmsk_phase);
>	xq = sin(gmsk_phase);
>%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>>Hello, 
>>
>>I am studying MSK modulation, does anyone know how to genrate a MSK
>signal
>>in matlab, pls help me..Thanks.
>>
>>Gon.
>>
>>
>>
>
>
>

thnks all