| 摘要 |
PURPOSE:To minimize the effective isotropic radiation output of a user satellite by using a command from an earth station corresponding to the data transmission speed of each user satellite so as to set optimizingly the relay band width and the transmission power of a repeater of a data relay satellite. CONSTITUTION:The data of a user satellite A is digitized by an encoder 1, modulated by a modulator 2 and a signal subjected to power amplification by a transmitter 3 is sent from an antenna 4. The sent signal is received by the tracking antenna 7 of a data relay satellite B and converted into an intermediate frequency via a low noise amplifier and a frequency converter 7. Band width changeover switches 8, 11 are thrown to the position of a broad band filter 9 when the data transmission speed of the user satellite A is high. Conversely, when the data transmission speed of the user satellite A is low, the switches are thrown to the position of a narrow band filter 10, then it is possible to increase the input C/N to a hard limiter 12 to 0dB or over. The earth station C uses a demodulator 23 to demodulate a signal from the user satellite A and the original data is recovered by a decoder 24.
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