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matlab help needed for Digital signal pulse shaping and baseband transmission

Started by pmm November 21, 2005
Hi all,

I am a student and quite new to dsp. I need some help with matlab. I am
trying to write the matlab code that will sample the input data stream u =
[+1 -1 +1 +1 -1] and make pusle shaping to nyquist raised cosine pulse
before being transmitted to the channel. Is it that the PAM block performs
the sampling function but only selects one pulse (middle pulse) to trigger
the Tx Filter? The nyquist roll off factor with the function g(t) =
(sin(pi*t/T)./(pi*t/T)).*(cos(alpha*pi*t/T)./(1-(2*alpha*t/T).^2)) must be
used to get the pulse shaping done? How can i plot the input data stream to
the continuous time signal after sampling and the corresponding output
response of the filter? 

Anyone can help me and give me some idea? 

Thanks in advance.

PMM


Data rate R give the bit period Tb (assuming M is 1).

Tb = 1/R. Larger the data rate R, larger the ISI

A pulse g(t)*d(i) is transmitted at each bit period Tb and the
accumulation of all such signals should give you the transmitted signal.