| 摘要 |
PURPOSE:To eliminate a complicated mechanism and a complicated coordinate conversion to measure easily a receiving electric field, by receiving a signal by an antenna which is mounted on a ship and has an automatic tracking function and correcting the fluctuation due to rolling and pitching of the ship. CONSTITUTION:A parabola 3 of an antenna receives radio waves, which are transmitted from an artificial satellite, through a subparabola 1 and supplies them to a directional coupler 5 through a band pass filter 4. Only off-beam components are taken out from the AGC voltage corresponding to a receiving field from a frequency converter 10 by a tracking error detector 11, and the synchronization with a reference phase of a two-phase generator of a scanner 2 is detected to generate a tracking error signal. This error signal is compensated in respect to the phase and the acceleration error by servo control amplifiers 12 and 13 and is supplied to motors 16 and 17 through power amplifiers 14 and 15, and the parabola is controlled to face to the artificial satellite. Meanwhile, in case that the field intensity is corrected, a switch S1 is switched to CAL, and the antenna is offset in the direction of no influence of the input field to supply a reference signal 6 for correction. |
