FRANÇA, R. M. V.; FRANÇA, Rosângela Maria Vilar.
Résumé:
Soft-decision techniques have been used with
some types of codes for several years, improving their error
correcting capacity without adding extra redundancy.
This thesis deals with the study and hardwa_
re implementation of a soft-decision technique applied to a
code division multiplex system. This system,which has the cha_
racteristics of an error correcting code with variable redundancy,
is based on Walsh functions. The multiplexing process
produces a systematic variation of the intersymbolic influence
of the digits, automatically increasing the error correc -
ting capacity, as the number of active channels decreases.
The basic theoretical description of the
system, the circuits used and, a discussion of the results are
presented.
