| 摘要 |
A communications system, such as an identification system for use in animal feeding or milking parlours, has a driver (16; 200; 320; 350) which supplies current to an antenna (for example, 1; 68; 168; 208; 306; 352). That current causes the antenna to emit power (in the form of a time varying magnetic or electromagnetic field) which energises a transponder (220) operable to transmit an identification signal (such as an RF signal). The driver and antenna are connected to a parallel inductor which reduces the total inductance of the load seen by the driver. The antenna may be one of a plurality of antennae, all of which are connected to the same driver. Each antenna is located in a respective stall in a milking or feeding parlour so that the system can identify which animal is in which stall of the parlour at a given time.
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