Before anything, open Matlab and run demo. Select communication blocksets and play
with the PLL frequency synthesizer, GMSK and MSK demo systems.
Then, build a Simulink model for a GMSK transmitter, simulate it, and compare against
the block provided by Matlab.
Consider a block diagram of one particular implementation of a GMSK transmitter as
illustrated on the next page.
The data generator generates a symbol of either 1 or 1 randomly every Td = 1/1MHz.
That is each symbol is a square pulse of duration 1
μ
s and amplitude of either 1 or 1.
The data symbol is sampled every T = 1/100MHz = 10 ns. The sampling clock signal is
the 100MHz reference frequency signal generated using a source block.
For simplicity, realize the Gaussian filter in discretetime with a sample period of T =
1/100MHz = 10 ns.
A continuoustime Gaussian filter has unit impulse response given
by:
BT
d
product specifies the ratio of bandwidth of P(t ) to data rate, the modulation index h
is defined as:
For GSM, we are required to have: BT
d
= 0.3, h = 0.5. Evaluate P(t) at an appropriate
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '09
 Digital Signal Processing, Frequency, Lowpass filter, Finite impulse response, IIR filter block, continuoustime Gaussian filter

Click to edit the document details