| 摘要 |
A range gated strip proximity sensor uses one set of sensor electronics and a distributed antenna or strip (57) which extends along the perimeter to be sensed. A micro-power RF transmitter (10) is coupled to the first end of the strip and transmits a sequence of RF pulses on the strip to produce a sensor field along the strip. A receiver (12) is coupled to the second end of the strip, and generates a field reference signal in response to the sequence of pulses on the line combined with received electromagnetic energy from reflections in the field. The sensor signals comprise pulses of radio frequency signals having a duration of less than 10 nanoseconds, and a pulse repetition rate on the order of 1 to 10 MegaHertz or less. The duration of the radio frequency pulses is adjusted to control the range of the sensor. An RF detector feeds a filter capacitor (65) in response to received pulses on the strip line to produce a field reference signal representing the average amplitude of the received pulses. When a received pulse is mixed with a received echo, the mixing causes a fluctuation in the amplitude of the field reference signal, providing a range-limited Doppler type signature of a field disturbance.
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