A software defined radio comparison of received power with quadrature amplitude modulation and phase modulation schemes with and without a human

This paper presents the application of software-defined radio to the study of received power with and without a human in close proximity to a receiver transmitter pair. Software defined radio is increasingly being used in radio related research and teaching in Universities, Schools and Colleges. For teaching it is typically being used in the classroom in close proximity to users/observers. Because several transceiver sets are needed to compare two or more modulation techniques in conventional radio this presents significant challenges with matching, synchronisation and noise. Two or more separate systems are needed. In contrast with software defined radio simple changes to the ratios of I and Q modulators can execute several modulation methods using the same system. This paper examines the use of a typical software defined radio in close proximity to a user which is typical in a classroom situation. The most suitable of two modulation techniques for use with communication systems close to humans as a function of received power for a typical office environment is presented.