| 摘要 |
In a train control system wherein emitter beacons are located at predetermined points on the track near to one of the running rails, a device for detecting the position of a vehicle running on the railway track. It comprises into each beacon a radiating vertical-axis coil powered by an alternating current of a given frequency and, on board the vehicle, near to the corresponding rail, a pick-up unit including two pairs of receiver coils the axes of which are horizontal and perpendicular to the running rails. The associated circuits comprise two differential amplifiers connected to at least to two band-pass filters and a multiplier circuit in order to generate a positive signal when and only when the beacon is located between the two pairs of coils and the frequency of the beacon is the central frequency of the filters.
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