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             Overview 
            In satellite modem technology, the same transponder that is used 
              to deliver TV, is used to deliver Internet access. Satellite modems 
              have performance problems because they are used over shared media 
              and the high data rate is unidirectional, because the return channel 
              is via a 56K analog modem.  
            Transmission mechanism: In a DVB (digital video broadcasting) system, 
              the satellite transmits data to the dish at 6-33 Mbps. This dish 
              is connected to the PC through a DVB card. The PC is connected to 
              the Internet by an analog 56 Kbps modem. The service provider connects 
              the PC with the information provider and the satellite operator. 
              Spare transponder space on the satellite allows data to be broadcast 
              alongside normal digital programming in DVB/MPEG-2 multiplex mode. 
            Some of the different standards are DSS (Hughes proprietary), DVB 
              (ETS 300-421, an open standards consortium), and Primestar (ITU-R 
              217/11, being phased out). 
            Market Research 
            There were an estimated $100M in satellite modem sales in 1999. 
             
            Xilinx Solutions 
            Xilinx products provide significant value in a satellite modems 
              when used to interface various ASSPs together, resolving differences 
              in their interface control signals. The in-system programming capability 
              of Xilinx devices enables features to be upgraded while the product 
              is in the field, as well as decreasing the time-to-market for the 
              product. The Spartan™-II FPGA or XC9500XL CPLD devices are ideal 
              candidates for this low-cost application.  
            As satellite modems evolve into residential gateways they will 
              support multiple home networking interfaces. Spartan-II FPGAs provide 
              system integration and interconnectivity to these interfaces, hence 
              providing decreased time-to-market, increased time-in-market and 
              the rapid product proliferation in this market. Please view the 
              presentation to see 
              how Xilinx solutions can help you build products for this fast evolving 
              market place. 
                     Analog 
              / Dial-up 
               Cable 
               xDSL 
               ISDN 
               Satellite 
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