| 摘要 |
<p>A communications system operating in one or more frequency bands (L and S) of various number of channels per band. The system comprises an antenna and RF front end (32 or 33) for each band, a separate RF to IF down converter for each band, an analog-to-digital converter (41) converts analog signals to digital signals from a combiner (40), a digital down converter (44) converts the digital signals to baseband signals and a single digital processor (45) sequentially time shared among all the bands and channels. The IF for each band is centered at a succession of frequencies fo such that the spectra for each band are non-overlapping, with the center frequency. An analog-to-digital converter sampling rate is chosen such that one band is centered at baseband, and one or more other bands are centered at a specific relationship with the sampling rate such that each band is individually down converted to baseband by appropriate selection of tap weight multiplying sequences.</p> |
