Modular computer simulation of advanced telecommunications modems

摘要

A modular technique for modelling and simulating advanced telecommunications modems by computer is described. This technique is a unique FORTRAN simulation tool called MODSIM developed for modelling telecommunications modems and their associated channels. Modems ranging in data rate from 300 b/s to 19200 b/s can be modelled using the MODSIM technique. A detailed description of the simulation program is included. Special attention is given to some of the more challenging simulation areas, such as the echo canceller and adaptive equalizer modules. A specific example of how MODSIM was used to model the CCITT V.32 9600-b/s echo-cancelling modem is discussed. Performance results predicted by the simulation are provided and are compared with theoretical performance characteristics for this modem.