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:
Apr. 27, 1993
Filed:
May. 28, 1992
Lawrence G Decker, Loveland, OH (US);
Janet R Poston, Alexandria, KY (US);
Edward F Hume, Cincinnati, OH (US);
Cincinnati Microwave, Inc., Cincinnati, OH (US);
Abstract
A photodetector receives an optical signal and converts it an electrical signal. A pulse stretcher converts the electrical signal into a first signal which is characterized by having an increased pulse width relative to the electrical signal. A noise averager converts the electrical signal into a second signal which is representative of the average noise component of the electrical signal. A threshold reference is generated as a linear function of the potential difference between the first signal and the second signal. A first comparator compares the magnitude of the first signal and the threshold reference signal and generates a first logic output which is true if the magnitude of the first signal is greater than the magnitude of the threshold reference signal. A second comparator compares the magnitude of electrical signal and the threshold reference signal and generates a second logic output which is true if the pulse width of the electrical signal measured as a funtion of time is greater than the response time of the second comparator. A logic circuit generates an alert indication if the first logic output is true and the second logic output is false.