| 摘要 |
The invention provides an electro-optical distance meter comprising a light emitting element for emitting a distance measuring light, signal generators for generating two or more proximity frequencies, a modulation signal in which the two or more proximity frequencies are intermitted respectively and converted to pulses with a predetermined width, a projecting optical system for sequentially switching over and projecting intermittent modulated distance measuring light as converted to pulses with predetermined width by the modulation signal, a photodetection unit for receiving a reflected distance measuring light from an object to be measured and producing an intermittent photodetection signal with a predetermined pulse width, a reference signal generator for issuing reference frequency signals having a difference of a predetermined frequency respectively, a frequency converting unit for performing frequency conversion by mixing the intermittent photodetection signals from the photodetection unit and the reference frequency signals, corresponding to each intermittent frequency signals respectively and obtaining intermittent conversion signals with a pulse width, and an arithmetic control unit, wherein the pulse width of the intermittent photodetection signal is set up so as to be longer in a time duration than a period of the intermittent conversion signal, and in a case where the object to be measured is a moving object, the period of the intermittent photodetection signal is set to such speed that a phase change of the intermittent conversion signal due to moving of the moving object can be negligible, wherein the arithmetic control unit is configured so as to calculate a precise measurement distance value by obtaining the phase of the intermittent photodetection signal with respect to the two or more proximity frequencies, to calculate a coarse measurement distance value by obtaining a phase difference between the intermittent conversion signals, and to determine a distance by combining the coarse measurement distance value and the precise measurement distance value. |
