| 摘要 |
PURPOSE:To execute easily a reference setting of the time of adjustment and a self-diagnosis by sampling, by driving manually or automatically a self-diagnostic phase shifter attached to a modulating digital phase shifter, and detecting a phase displacement. CONSTITUTION:A high frequency signal applied to a high frequency signal input terminal 1 is brought to a phase modulation by a modulating digital phase shifter 2, and outputted through a self-diagnostic phase shifter 4 and a coupling circuit 5. A phase displacement of its signal is detected by a phase detecting circuit 7 and applied to a comparing circuit 8, and if it exceeds a reference value of a reference setting part 9, namely, an alarm point, an alarm generating circuit 10 outputs an alarm signal. When executing an adjustment, the self-diagnostic phase shifter 4 added onto a line is driven by a sampling phase signal generating circuit 11 having an automatic/manual changeover switch 12, and the alarm point is set by detecting a phase displacement by the phase detecting circuit 7. Also, when executing a self-diagnosis by sampling, the self-diagnostic phase shifter 4 is added, and the alarm generating circuit 10 is operated by an output of the phase detecting circuit 7 of that time.
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