Patent ID: 7095490
Filing Date: 2006-08-22
Classification: G01S

Abstract:
1. An electric distance meter, which irradiates measuring light to an object to be measured and measures a distance from a phase difference between the measuring light reflected by the object and internal reference light, comprising: a device configured to generate a modulation signal for measuring the distance; a pulse signal generation device configured to generate a pulse signal, which emits the measuring light as pulsed light; an AND circuit, which overlaps the modulation signal to only an interval of the pulse signal: a driver circuit, which drives a light emitting element based on a signal from the AND circuit to emit the measuring light; a frequency signal generation device configured to generate an internal frequency signal with a frequency different from said modulation signal; a mixing circuit, which mixes the pulse signal of the measuring light and the internal frequency signal, and generates a beat signal comprising the pulse signal as an intermittent difference frequency signal; a sampling circuit, which samples the interval of the pulse signal of the intermittent difference frequency signal at a predetermined interval; a storing device configured to store sampling data; and an arithmetic logical unit, which calculates the distance from a phase difference between a sine wave curve based on the sampling data of the reflected measuring light stored in the storing device and a sine wave curve based on the sampling data obtained through a reference optical path.