a satellite - based emission and reception device , intended to receive and to process radiofrequency signals originating from an uplink and then to emit the processed signals on a downlink towards terrestrial users , comprises a power divider , two independent frequency converters and two input demultiplexers connected respectively at the output of the two corresponding frequency converters , each frequency converter being controlled by a dedicated local oscillator , the two local oscillators operating at one and the same frequency , the two input demultiplexers comprising channel filters operating in different , disjoint frequency sub - bands spaced apart in frequency , two adjacent frequency sub - bands being filtered by two channel filters belonging to different input demultiplexers .