A study of modulation for digital mobile telephony

This paper describes a digital modulation technique for VHF and UHF land mobile telephony. After describing the requirements of voice coding and digital modulation for the narrowband digital voice transmission in the VHF and UHF land mobile radio channels, the feasibility of digital mobile telephony is clarified by showing the realizability of a digital modulation satisfying the requirements and supported by a few of the experimental test results. The remained technical problems, which should be solved in the near future, are enumerated.