Improving the Noise Immunity of the Modem with the Optimal Finite Signals that do not Cause Intersymbol Interference in a Linear Communication Channel

Abstract

A new structure of data transmission system proposed based on the synthesis of digital optimal coherent modem with signals that do not cause intersymbol interference at the output of a band limited communication channel. New analytic expressions for optimal finite signals at the input and output of the low frequency equivalent of the communication channel are presented. The potential noise immunity for the digital optimal coherent modem is calculated. A comparative analysis of noise immunity of the known and new schemes of the optimal coherent modem is carried out. Numerical results and experiment confirm the increased energy efficiency of the proposed modem.

Keywords

• digital coherent modem
• bandwidth-limited communication channel
• intersymbol interference
• optimal finite signals
• noise immunity