Parameters recording system defining vehicle movement - utilises one channel on which differences from previous recorded value are made

摘要

Movement of a vehicle on tracks is determined by recording various parameters defining the movement such as actual speed and time and any signalling events. Logic signals permit recording of the parameters on the same channel. An analogue signal representing speed is compared with voltage from digital to analogue convertor which receives its input from a counter to which the comparator output passes. At balance counter output oscillates between values above and below the speed. Speed difference from last recording is determined by counters to which speed tolerance values are applied. A circuit memorises values which exceed tolerances and starts the recording.