Reply by Florian Toulouse●March 13, 20062006-03-13
Hello ,
I despair on how to regain the initial information from the seperate I
and Q bits after MSK modulation/demodulation.
If
d(t) is the data, a sum of delta pulses
g(t) is the frequency response (MSK: REC) and
c(t)=g(t)*d(t) (* convolution !)
then
phi(t) is the phase , which is calculated by cumsum(c(t))
(MSK:"linear ramps up and down according to the bit")
and thus exp(j *phi(t)) represents the equivalent complex baseband
signal s(t).
This works very well. A plot of Real(s(t)) and Imag(s(t)) gives
the typical sin and cosine forms of the I and Q channel.
My question: After Demodulation , e.g. with matched filtering, I get
two bit streams I and Q but how do I demultiplex them to recuperate the
d(i) ?
Thanks a lot
Florian Toulouse
Berlin / Germany