Digital Data Transmission in a PAM Communication System

Abstract

This paper presents the results of an experimental evaluation of the effectiveness of digital data transmission in a pulse-amplitude modulation (PAM) communication system. A PAM communication system was simulated and equipment was developed to obtain experimental results indicative of PAM's effectiveness in transmission of digital data. The results consist of word, channel, and bit error probability curves for different numbers of digital bits per PAM channel. The digital bits were converted to analog voltage levels which amplitude-modulated selected PAM channels. After decommutation the digital bits were recovered from the analog voltage levels by an analog to digital conversion. The data indicates that the number of bits per channel should be 4 or less depending upon the digital data quality requirements. The error probability curves can be used to determine whether or not a PAM communication system can telemeter digital data within given constraints. In addition, the results provide guidelines for the implementation of digital data in a PAM system.