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:
Aug. 20, 2002
Filed:
May. 12, 1999
Andrew L. Strodtbeck, El Segundo, CA (US);
Hughes Electronics Corporation, El Segundo, CA (US);
Abstract
An apparatus for estimating an error rate in a digital communication system is provided. A satellite ground station or a user satellite transmits a digital data stream to a relay satellite. The relay satellite calculates an error rate associated with the data stream by sanding one or more bits of the data to an error rate estimator. Each bit sent to the error rate estimator is delayed, inverted, and exclusive-ored (XOR) with the next bit in the data sequence. By averaging the output of the exclusive-or an analog representation (i.e., a moving average) of the error rate is produced. The analog estimate may then be converted to a digital signal. The error rate estimate may be returned to an equalizer within the relay's demodulator, thereby allowing the on-board equalizer to tune the demodulator for a minimum error rate. The error rate estimate may also be multiplexed into the spacecraft telemetry system. Once received by a receiver station, the telemetered error rate information can be used to monitor link quality or to tune distortion mitigation systems on the relay or at the transmit site.