Frequency-Division Multiplex Communications for the Land Mobile Radio Service.

摘要

Although there are numerous systems of multiplex transmission,the report treats only frequency-division multiplex (FDM) systems involving either FM/FM,FM/SSB,or SSB/SSB. Among these systems, a comparison is made of their relative potential for base-to-mobile communications. Mobile-to-base transmissions by multiplex techniques are not contemplated. A relatively small number of simultaneously active message signals (probably less than a dozen,but possibly more) is assumed in the analysis. Further assumptions are made about the probable activity of these subchannels. The evaluation indicates that some forms of multiplexing offer the possibility of increasing the efficiency of spectrum utilization by land mobile services. No serious search for ways and means of increasing the number of message channels available to land mobile communicators can be considered complete until a full exploration of multiplex techniques is made.