DISTANCE MEASURING APPARATUS

摘要

The distance measuring device includes a light source ( 1 ), a light-receiving sensor ( 2 ), a timing controller ( 5 ), a distance calculator ( 6 ), and a delay controller ( 8 ). The timing controller ( 5 ) outputs a modulation signal and plural reference timing signals. The modulation signal is a square wave signal having high and low level periods appearing alternately. Each of the high and low level periods has its length randomly selected from integral multiples of a predetermined unit time period. The reference timing signals include a signal having the same waveform as that of the modulation signal and a signal having the same waveform as that of the inverted modulation signal. The light source ( 1 ) varies an intensity of the light in concordance with the modulation signal. The delay controller ( 8 ) delays the plural reference timing signals by the delay period ( Td ) to create plural timing signals respectively. The light-receiving sensor ( 2 ) accumulates the electric charges generated within the reception time period, with regard to each of the timing signals. The distance calculator ( 6 ) calculates the time difference (Ä) from amounts of the electric charges respectively associated with the timing signals, and calculates a distance ( L ) to the target ( 3 ) on the basis of the time difference (Ä) and the delay period ( Td ).