| 摘要 |
An interrogator-responder system for detecting the entry of personnel into a danger zone, has a transmitting arm including a microwave oscillator 1, a first directional coupler 4, a modulator 6, and a second directional coupler 8, feeding a transmitting antenna 9, and a receiving arm including a push-pull mixer 16 fed by a receiving antenna 12 which receives a response signal of doubled frequency produced by a responder R, the push-pull mixer being also supplied with a frequency doubled component extracted from the transmitting arm via 4. A test arm is provided to extract energy from the transmitting arm at 8, double its frequency at 23, and supply it to the receiving arm, by-passing the responder. <IMAGE> |
