Continuous waveforms from a binary modulator

Abstract

This paper explains how a low rate purely digital code labeling a trellis encodes representative RF signals as needed for wireless communications. This new approach allows for a completely digital transmitter i.e. there are no analog stages required for up-conversion. The binary stream coming out of a finite state machine is simply filtered and then directly radiated. GMSK is used as a motivating example and typical SNR values and data rates achieved are presented; however, other modulation schemes can be equally well represented using this technique.