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:
Jul. 16, 1985
Filed:
Sep. 28, 1982
Ake N Sewerinson, Port Coquitlain, CA;
AEL Microtel, Limited, Burnaby, CA;
Abstract
Differential encoding is commonly used in data transmission systems because it allows correct recovery of the data even though the polarity may have changed during transmission. However, single errors which are introduced result in double errors, i.e., error of an even number following the differential decoding process. Because many error detection schemes rely upon parity checks, which look for an odd number to determine if an error has occurred, the conversion of the single error to a double error means that single errors normally would not be detected. A precoder is used to introduce correlation by modulo two addition of the precoded present digit with a selected combination of past digits. The differential decoder will still provide double errors but a subsequent decoder, which reverses the precoding process, at least partially changes double errors into errors of an odd number.