| 摘要 |
<p>An improved spread spectrum communications system is provided for establishing full-duplex voice/data radio communications within a single specified FCC ISM band. Spectrum spreading is performed relative to a plurality of sub-bands respectively defined about the lower and upper band-edges of the prescribed ISM band and having spectral roll-off characteristics which satisfy FCC requirements for radio frequency radiation outside the ISM bands on the corresponding band-edges thereof. Full-duplex operation is implemented by the use of digital MSK modulation (52) and associated filtering (58) in order to conserve available bandwidth and accommodate the filtered, modulated signal within the sub-bands defined in the prescribed ISM frequency band, and the system is capable of being easily interfaced to related digital communications services.</p> |
