NEW DIGITAL MOBILE RADIO TECHNOLOGIES

In order to develop a digital mobile radio unit it is necessary to achieve highly precise and efficient pi/4 shifted QPSK transmission in a TDMA burst RF channel. This paper discusses the configuration of a digital mobile radio and explain the prerequisite conditions for its various sub-systems. Next, as new fundamental element in the mobile radio technologies, we propose an RF quadrature modulator, adaptive carrier tracking demodulator, linearized saturation amplifier with bi-directional feed control, as well as a digital loop preset synthesizer. Also, the configuration of each of the above and their superior features are demonstrated. In addition, the efficacy of these basic sub-system technologies in designing compact and low power consumption mobile radio units is shown.