| 摘要 |
<p>PROBLEM TO BE SOLVED: To shield effectively unrequired signals from an antenna when an automatical noise level control circuit is activated, and to enhance the probability of reception system gain setting. SOLUTION: This embodiment comprises: an antenna 1 for gathering reflection waves from a target; a RF(radio frequency) front end 2 for amplifying RF signals from the antenna 1 and converting the RF signals into IF (intermediate frequency) signals; an IF amplifier 6 for amplifying output signals of the RF front end 2; an automatical noise lever control circuit 7 for making constant a gain of a reception system circuit and playing a roll for preventing signals noise level variations; and a mechanical shutter 9 for shielding the RF signals from the antenna 1.</p> |
