Optical distance measuring apparatus
US5204732A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 6, 1992 |
| Grant date | Apr 20, 1993 |
| Priority date | — |
| Expiry date | Mar 6, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S17/36
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical distance measuring apparatus is disclosed which is operable in accordance with a phase difference detecting process wherein a processing system including a central processing unit and a digital type mix-down circuit detects and calculates a phase difference between the electrical phase of a signal output from a light receiving portion in response to receipt of a reflected light beam and the electrical phase of a reference signal output from a reference oscillator so as to determine a distance between the apparatus and a object spaced at a distance to be measured with reference to the electrical phase of a local oscillation signal output from a local oscillator. A second circuit system of the processing system on the light receiving side includes a ladder resistance type attenuation circuit, a multiplexer, an veriable gain current amplifier, a wave shape correcting circuit and a signal amplitude detecting circuit. When the signal amplitude detecting circuit detects that the signal derived from the reflected light beam has an amplitude in excess of a predetermined value, the central processing unit controls the multiplexer so as to reduce a magnitude of the amplitude. In a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.