SATELLITE COMMAND SIGNAL GENERATING APPARATUS

摘要

PURPOSE: A satellite command signal generating apparatus is provided to ensure a security of an artificial satellite desired to be tested by generating and transmitting an upward satellite command signal required by a satellite communication system and a clock signal for synchronization and re-receiving the transmitted signal. CONSTITUTION: A FIFO(6) stores a satellite command signal inputted to a V ME(Versa Module Euro)bus input/output ports(1,2). A parallel/serial converter(7) converts a parallel signal stored in the FIFO(5) into a serial signal. An encoder(8) converts the serial signal converted in the converter(7) from an NRZ-L signal level to an NRZ-M signal level. An RS422 line driver(9) converts the level-converted signal into a satellite transmission signal level. A line driver(11) converts a level of a signal inputted from a satellite command/clock signal input port or external clock signal input port(5). A decoder(12) converts a signal applied from the line driver(11) from the NRZ-M signal level to an NRZ-L signal level. Serial/parallel converter(13,14) converts the signal converted in the decoder(12) into a parallel signal. A comparator(15) compares the signal converted by the serial/parallel converter(13) with a synchronous pattern mixed with a transmission command signal. A FIFO(17) stores a reception signal converted by the serial/parallel converter(14) if the signal and the pattern are identical upon comparing. Counters(10,16) synchronizes a clock signal, and a satellite command signal is modulated by a satellite modulation board into an RF signal and transmitted to a satellite.