A multiplex system for simultaneous voice and data transmission using narrowband FM in private mobile radio

An integrated system, suitable for the simultaneous transmission of speech and data messages in private mobile radio based on narrowband frequency modulation, is presented as a novel technique offering compatibility with Band III and increased efficiency of spectrum utilization. Some of the problems involved in the practical implementation of the integrated system are examined. The authors present and discuss the results of the performance evaluation of a prototype system based on this technique are presented and discussed. It is shown that satisfactory operation can be obtained in both single and integrated configurations.<
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