Trackside axle counting, or train velocity measuring device - uses variation in reception coil voltage to switch voltage divider ratio

摘要

The device uses a co-operating AC transmitter and a reception coil providing a varying reception voltage uoon oassage of the train wheels. This voltage is used to feed an amplitude dependant frequency to an evaluation circuit. The reception voltage is converted into a DC voltage controlling a trigger used to switch a frequency divider supplied from a rectangular voltage generator and providing two different frequencies. The frequency divider is switched in the opposite sense by a blocking signal supplied by a voltage monitor for the 05voltage,whenafalseDCvoltagelevelisdetected.