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:
Nov. 03, 1998
Filed:
Dec. 04, 1996
Xiaojun Li, Boynton Beach, FL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A selective call communication system (10) transmits a frequency hopped spread spectrum signal as a Reed Solomon code word modulated as a four-level frequency shift keying (4FSK) signal. A base site transceiver (150) receives the signal on a plurality of narrow band channels and a DSP (152) performs an FFT on the signal. The DSP (152) has a comparator (342) that computes energy of an 4FSK symbol. The comparator (342) establishes a ratio of a maximum energy and a next largest energy to an eye-opening threshold to indicate a probability of error. A determinator (344) in response to the probability of error determines when there is a fade, an erasure marker (346) marks a position of a Reed Solomon symbol in the fade as an erasure and error correcting code (348) corrects errors in the Reed Solomon code word with the marked erasure.