LASER DISTANCE MEASURING INSTRUMENT

PURPOSE:To remove a signal only even when the noise goes to be the level close to the signal by making a laser beam irradiated to a distance measuring object into the double pulse having the stipulated interval. CONSTITUTION:The double pulse laser beam generated by the double pulse laser device is irradiated toward distance measuring object 4, and simultaneously, enters a photoelectric converting device for starting, goes to be a starting signal of a time measuring instrument 10 and starts the timing. A reflecting optical system 5, enters a photoelectric converter 6 for stopping, and thereafter, the beam is wave-height-discriminated and waveform-shaped by a discriminator 7. An AND circuit 9 obtains an AND of a direct output signal from the discriminator 7 and a signal through a delaying circuit 8. The circuit 8 gives the delay for the same time only as the stipulated double pulse interval t0 of the laser beam. For this reason, the pulse is outputted from the circuit 9 only when the output signal from the discriminator is a double pulse having the interval t0 and the pulse due to the noise is deleted.