| 摘要 |
The method includes radiating an RF signal within a time Tt, receiving a reflected signal within a fixed time Tr equal in duration to the fixed time Tt of the radiated signal plus a delay &tgr;d between the end of the signal radiation and the beginning of the reflected signal reception. Once a modulated component is detected, a level of the component is measured and the reception time of the reflected signal is modified. This is carried out until the level of the modulated component decreases relative to that of the initially reflected RF signal and until the signal stops coming in. A distance is further determined from the reception time of the reflected signal with the modulated component. The method can be implemented using a microwave locator comprising a modulator and a transmitter which includes an oscillator, a power splitter and a transmitting antenna. A receiver comprises a receiving antenna, a microwave receiver, a preamplifier/demodulator and a signal processing unit. The modulator is tunable. The apparatus further includes a first pulse modulator in the transmitter and a second pulse modulator in the microwave receiver. The modulator has a control output which is connected to a control input of the second pulse modulator so that the receiver receives the reflected signal with a delay relative to the end of the signal radiation by the transmitter, and the enable time of the microwave receiver is modified. The signal processing unit measures a level of the modulated component.
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