Title:
PROXIMITY SENSOR
Document Type and Number:
Japanese Patent JP3505961
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To prevent the frequency of an oscillation circuit from being limited to be a frequency discriminated by a frequency discrimination circuit with respect to the high frequency oscillation proximity sensor.
SOLUTION: The sensor is provided with an oscillation circuit whose frequency changes with a distance up to an object and with a local oscillation circuit 3 that is oscillated at a prescribed local oscillation frequency. A multiplier 2 provides an output denoting the sum or the difference between the outputs of the circuits 1 and 3. A low-pass filter 4 extracts the difference frequency signal obtained by the multiplier 2 and a frequency discrimination circuit 5 discriminates the signal. Then the local oscillation frequency of the local oscillation circuit 3 is selected to select the frequency of the oscillation circuit 1 and then hence the degree of freedom of frequency selection is enhanced.
Inventors:
Tomofumi Motouji
Michiaki Taniguchi
Michiaki Taniguchi
Application Number:
JP17147997A
Publication Date:
March 15, 2004
Filing Date:
June 27, 1997
Export Citation:
Assignee:
Omron Corporation
International Classes:
G01B21/02; G01D5/243; G01V3/10; H03K17/945; H03K17/95; (IPC1-7): H03K17/95; H03K17/945
Domestic Patent References:
| JP637620A | ||||
| JP522104A | ||||
| JP55133716A | ||||
| JP5350476A | ||||
| JP638361U |
Attorney, Agent or Firm:
Yoshiki Okamoto (1 person outside)