초록 ▼

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

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.

대표청구항 ▼

A dual mode portable digital signal transceiver providing communication in a terrestrial mode and a satellite mode, said transceiver providing communication in said terrestrial mode via a terrestrial network using a terrestrial transmit frequency band and a terrestrial receive frequency band, said t

A dual mode portable digital signal transceiver providing communication in a terrestrial mode and a satellite mode, said transceiver providing communication in said terrestrial mode via a terrestrial network using a terrestrial transmit frequency band and a terrestrial receive frequency band, said transceiver providing communication in said satellite mode via a satellite network using a satellite transmit frequency band and a satellite receive frequency band, said terrestrial transmit frequency band and said satellite transmit frequency band being substantially adjoining, and defining transmit bands of said transceiver, and said terrestrial receive frequency band and said satellite receive frequency band being far apart, and defining receive bands of said transceiver, said transceiver comprising: synthesizer means for synthesizing a first frequency for modulation and a second frequency for demodulation; and divider means for dividing said second frequency to supply a third frequency for demodulation; wherein signals transmitted in any of said transmit bands of said transceiver are modulated using said first frequency, wherein signals received in one of said receive bands of said transceiver are demodulated using said second frequency, and wherein signals received in another of said receive bands of said transceiver are demodulated using said third frequency.