| 摘要 |
PURPOSE:To enable a communication between a communication satellite and the ground by fixing the direction of an antenna with a signal from a level holding circuit in case a beacon signal is absent. CONSTITUTION:The device consisting of a beacon receiving device 1, an antenna tracking device 4, an antenna driving device 5, a parabolic antenna 6, etc., is provided with the level holding circuit 2 which holds a level when the beacon level falls between the beacon receiver 1 and antenna tracking device 4. The receiver 1 inputs a beacon signal BS received by the antenna 6 and also detects it, thereby outputting the beacon level signal BLS. Then even if the signal BLS is absent owing to the trouble of the receiver 1, the holding circuit 2 detects that and inputs the last level-fixed signal which is held before the trouble to the tracking device 4 when the level drops below a reference value to output driving signals X and Y which do not move the antenna to the driving device 5, thereby fixing the antenna 6.
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