Title:
【発明の名称】光学式測距装置
Document Type and Number:
Japanese Patent JP2656835
Kind Code:
B2
Abstract:
PURPOSE:To make it possible to prevent erroneous measurement of a distance due to induced noise signals by setting the shift phase and the level of a shift reference signal so that the induced noise signals are cancelled, and adding the shift reference signal to the output of a first photodetector. CONSTITUTION:The phase of a reference signal f0 is shifted, and shift reference signal is outputted from a phase shift circuit 13. The shift reference signal is added to the output of a first photodetector 5a and the result is outputted to a first mixer circuit 9a with an adder 7. The circuit 13 and the adder 7 are provided in this way. When a body to be detected X is not present, the output of the circuit 13 is set so that phase is reverse to the phase of the induced noise signal outputted from an I/V converter circuit 6a and the level is equal to the level of the signal. Therefore, the introduced noise signals are offset when the output of the circuit 13 and the output of the circuit 6a are added. The phase information when the body X is not present becomes random, and the phase does not gradually approach the phase of the introduced noise signal. Therefore the erroneous measurement of a distance can be prevented. Furthermore, the erroneous operation due to the increase in phase noises when the received light signal is decreased can be prevented.
Inventors:
TAKADA JUJI
MATSUDA HIROSHI
MATSUDA HIROSHI
Application Number:
JP25010589A
Publication Date:
September 24, 1997
Filing Date:
September 26, 1989
Export Citation:
Assignee:
MATSUSHITA DENKO KK
International Classes:
G01C1/02; G01S17/36; (IPC1-7): G01S17/36
Domestic Patent References:
| JP5827963U | ||||
| JP5839578U |
Attorney, Agent or Firm:
Ishida Chochichi (2 outside)