| 摘要 |
<p>PURPOSE:To receive a searching radar signal, by providing a video switch (SW) opening and closing by the output signal of a control circuit between a video amplifier and a video auxiliary amplifier to return the same to a normal operation state immediately after the stoppage of transmission. CONSTITUTION:A received searching radar signal is sent to an FET amplifier 2 and a detector 3 and the detection output of said detector 3 is amplified to a level necessary for triggering a control circuit 6 by a video auxiliary amplifier 5 through a video amplifier 4 and SW 12. The circuit 6 triggered by said amplified output outputs a positive voltage pulse signal to SW 12. During a transmission period, a positive voltage pulse becomes an H-level not only to bring SW 12 to a closed state but also to cut off the output of the amplifier 4. Other than the transmission period, a positive voltage level becomes low to bring SW 12 to an open state and the output of the amplifier 4 is inputted to the amplifier 5. Since SW 12 is brought to a closed state during transmission period to prevent an input signal of an H-level from being applied to the amplifier 5, the searching signal can be received immediately after the stoppage of transmission.</p> |
