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:
Jun. 02, 1992
Filed:
Dec. 14, 1989
Clyde Smith, Lake Ronkonkoma, NY (US);
Fiber Options Corporation, Bohemia, NY (US);
Abstract
The disclosure is directed to an apparatus and method for receiving and processing an optical signal representative of electronic information. In an embodiment of the invention there is provided a light-emitting diode which is reverse biased to receive the optical signal and convert the optical signal to an electronic signal. Means are provided for determining time periods during which the electronic signal produced by the light-emitting diode is below a predetermined threshold. Means are provided for generating a dark current error signal indicative of a sampled output of the light-emitting diode during said time periods. Means are also provided for holding the error signal during other time periods when the electronic signal produced by the light-emitting diode is not below the predetermined threshold. Finally, means are provided for modifying the electronic signal produced by the light-emitting diode as a function of the held error signal to obtain an output electronic signal. In the disclosed embodiment, the light-emitting diode is reverse biased and coupled across an input of an operational amplifier which is arranged to produce an output voltage that depends upon the current in the light-emitting diode. A resistor is coupled between the output of the operational amplifier and the input of a voltage buffer. A threshold detector determines when the output of the voltage buffer is below a predetermined threshold, and produces an enable signal when the voltage buffer output is below the threshold. A sample-and-hold circuit samples the output of the buffer in response to the enable signal. The output of the sample-and-hold circuit is coupled via a resistor to the input of the voltage buffer. An output terminal is coupled to the output of the voltage buffer.