Baseband numeric transmission

Baseband data transmission via m-ary NRZ raw code

This script is intended to illustrate the concepts of eyediagramm, constellation, ISI and to understand the effects of additive noise power, channel frequency band restriction, number of possible states within a symbol period, affecting the quality of the transmission.
Three methods are employed for low-pass filtering:
- classical low pass filter (actually two order Butterworth) creating ISI.
- raised cosine filter in order to illustrate the possibility of
suppress ISI .
- Pseudo filtering by increasing risetime and falltime of ideal rawcode .
Levels of signal transmitted as well as noise level are variables,
allowing thus the possibility to show the effects of the number of states by symbole time on the possibility to recover without error the information in a given Signal/Noise environment.

Simulations results are:
- Eye diagram of transmitted rawcode: determine if recover of data is possible and transmission delay of the channel used .
- Temporal shape of raw code transmitted, before and after filtering.
- Power Spectral Density (PSD)of rawcode transmitted .
- Constellation or trajectory from point to point of the constellation.