Portable transmitting and receiving device for two-mode digital signals

Abstract

Abstract The invention relates to a portable, dual-mode digital radio communication device allowing communications, on the one hand via a terrestrial network (first mode) and, on the other hand, via a satellite network (second mode). This device comprises means (215) for synthesising a first modulation frequency (213i) for modulating (211i, 211Q) the signals transmitted in the two modes, and a second transposition frequency (229) used for demodulating (228i, 228Q) the signals received in the said two modes, and means (245) for dividing the said second transposition frequency (229) delivering a third transposition frequency (244) for demodulating (241) signals received in one of the said modes employing a signal reception frequency band which is very far from the other frequency bands used. Thus it is possible, from a single pure synthesised carrier (229), in a first mode, to perform transposition with direct conversion and, in the second mode, to perform transposition to intermediate frequency followed by the same transposition with direct conversion. <IMAGE>

Inventors

• 👤 Gerard Auvray

Bibliographic Details