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:
Feb. 23, 1999
Filed:
Mar. 14, 1997
Yusuke Ota, Mountain Lakes, NJ (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
A DC coupled burst mode optical receiver circuit having improved sensitivity and improved dynamic range. The output of the receiver's photodiode is single endedly amplified by a main preamplifier and the main preamplifier's output is then converted, using an operational amplifier, e.g., with a gain of 1, to a differential signal which swings symmetrically around a threshold level. More specifically, the output of the main preamplifier is connected to one input of the operational amplifier. The output of a tracking preamplifier, which is identical to the main preamplifier, is coupled to the other input of the operational amplifier. The output of the tracking preamplifier is used to match the DC voltage of the main preamplifier, e.g., by being noise-free and by tracking changes in supply voltage, temperature, and the like. It is used to set the DC reference voltage for the standard operational amplifier functions. Between one output of the operational amplifier and the opposite sign input thereof is connected an automatic threshold controller (ATC). The ATC insures that the threshold level for determining the value of the logic value of the received signal is at the middle of the signal supplied from the main preamplifier. Preferably, the main preamplifier, the tracking preamplifier, the operational amplifier and the ATC are manufactured on a single integrated circuit. Optionally, a transimpedance resistor of both the main preamplifier and the tracking preamplifier are clamped to a predetermined maximum level, e.g., using a high-speed Schottkey diode, to enhance the dynamic range of the receiver.