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The SS/FDMA (subchannel-switched frequency-division multiple-access) system has been proposed to enhance the interbeam connectivity of a multibeam satellite under FDMA operation. The authors address specific applications of the SS/FDMA system to FDMA-type trunk lines, a very small aperture terminal network, and a digital point-to-point network and clarify the benefits of the SS/FDMA system. It is noted that the SS/FDMA system can confine each individual service or network in separate satellite channels with sufficient interbeam connectivity while not imposing any constraint on the interbeam connections of the other satellite channels, which considerably enhances transponder utilization efficiency of the whole satellite. A breadboard model of the 1.5-GHz-band bandwidth-variable SAW (surface acoustic wave) filter matrix is described in terms of its detailed structure, its electrical performance, and its transmission characteristics. The breadboard model shows good electrical performances, which promise the realization of the SS/FDMA system in the 1990s. > |
