Laser beam system for measurement of physical quantities - evaluates distance in terms of propagation time by heterodyning and pulse counting at defined fundamental frequency

摘要

The distance (3) of, e.g. a vehicle (1) from an obstacle (4), is measured by a laser beam (6) whose reflection is detected and evaluated by a receiver (7). In a parallel oscillatory circuit (8) one node (9) is connected to a comparator (10) feeding pulses to a reversible counter (11), multiplier (12), digital display (13) and printer or calculator (14). An active system may react directly on a speed regulator (17). A passive system may reinforce the visual display with an audible warning (16). USE/ADVANTAGE - For e.g. distance measurement from fog banks confronting road traffic sufficiently early warning is given for safe adaptation of driving.