The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 26, 2002
Filed:
Oct. 15, 1999
Orest Fedan, Belmont, MA (US);
Other;
Abstract
An object detector which illuminates an area with a pulsating beam of light and measures light reflected back by an object in the beam. The light source is chopped by three different chopping frequencies. The light detector uses the highest frequency to reject out of band ambient signals and noise, uses the middle frequency for synchronously detecting the reflected signal, and uses the lowest frequency to ratio the output to the noise floor. The light detector uses linear gain prior to filtering out of band ambient signals to avoid intermodulation effects. The light detector uses logarithmic gain after the filtering to avoid overload and transient effects, without requiring an automatic level control circuit.