| 摘要 |
PURPOSE:To perform stable transmitting and receiving operation without being affected by air temperature nor a weather state by performing the temperature compensation of the gain of a transmitting power amplifier and the compensation of variation in propagation loss due to rainfall attenuation, etc., at the same time by an open-loop control system which uses one variable attenuator. CONSTITUTION:The open-loop control system is so constituted that a signal which is in inverse proportion to the temperature of a temperature detector 9 installed in the transmitting power amplifier 7 and a signal proportional to a beacon reception level obtained by detecting the output of a beacon reception frequency converter 6 by a detector 10 are put together into one signal to adjust the attenuation quantity of the variable attenuator 12. When the temperature of the transmitting power amplifier 7 varies, the attenuation quantity of the variable attenuator 12 varies to vary the input level of the transmitting power amplifier 7, thereby performing automatic compensation so that the transmission output level becomes constant. Further, when the propagation loss increases owing to a rainfall, etc., the attenuation quantity of the variable attenuator 12 is decreased to raise the output level of the transmitting power amplifier 7, thereby performing the automatic compensation so that the reception level of a satellite becomes constant.
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