Distance measuring apparatus based on the pulse travel time method

US4344705A · kind A · utility

Assignee

• Endress u Hauser GmbH u Co. · DE

Inventors

• Gunter Kompa · Lippstadt, DE
• Don J. R. Stock · Lonsee, DE

Key dates

• Filing date: Mar 7, 1980
• Grant date: Aug 17, 1982
• Expiry date: Mar 7, 2000

Classification

• Technology area (CPC G): Physics
• CPC primary: G01S7/483
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Distance measuring apparatus based on the pulse travel time method comprising a light pulse generator for generating periodic light pulses, a transmitting optical system for transmitting the light pulses, a receiving optical system for receiving the echo pulses produced by reflection of the light pulses at a target object, a photoelectric transducer for converting each echo pulse to an electrical measuring pulse, means for generating electrical reference pulses in predetermined time relationship to the transmitted light pulses, a time transformation stage operating by the sampling method and comprising a sampling pulse generator for generating periodic sampling pulses whose period is slightly different to the period of the transmitted light pulses, a first sampling circuit receiving the sampling pulses and the reference pulses and producing time-transformed reference pulses by periodically sampling a large number of successive reference pulses by means of the sampling pulses, and a second sampling circuit receiving the sampling pulses and the measuring pulses and producing time-transformed measuring pulses by periodically sampling a large number of successive measuring pulses by me…