Portable digital signal transceiver providing communication via a terrestrial network and via a satellite network

摘要

A dual mode portable digital radio transceiver for communicating via a terrestrial network (first mode) and via a satellite network (second mode) synthesizes a modulation first frequency for modulation of signals transmitted in both modes and a conversion second frequency for demodulation of signals received in the two modes. It divides the conversion second frequency supplying a conversion third frequency for demodulation of signals received in one of the modes using a signal receive frequency band far away from the other frequency bands used. It is therefore possible, using a single synthesized pure carrier, to carry out direct conversion in a first mode and intermediate frequency conversion followed by the same direct conversion in the second mode.