Alignment of electro-optical rangefinder with distant reflector - using sensitivity of human ear to detect frequency deviations

摘要

The rangefinder is aligned by means of a transmitter for beaming modulated radiation, a receiver for converting the incident radiation into electrical signals and a phase meter or chronometer for comparing the phase relationship or response time for the emitted and the incident radiation to determine the desired range. The rangefinder (1, 4, 5) is also equipped with a generator (6, 7, 8) to produce an acoustic auxiliary directional signal whose frequency varies in accordance with the intensity of the incident radiation. The rangefinder can also be equipped with a visual directional unit.