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:
May. 20, 1997
Filed:
Jul. 12, 1993
Takashi Kaku, Kawasaki, JP;
Toyomi Obikawa, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
In a modem, after scrambling data which are time-divided into main data and secondary data, a 2 W-4 W conversion circuit sends the data to the two-wire line. An estimated echo component is subtracted from a signal which is available from the 2 W-4 W conversion circuit. Following this, the signal from the 2 W-4 W conversion circuit is demodulated, descrambled and separated into main data and secondary data. A generator polynomial for scrambling is different from a generator polynomial for descrambling. The modem comprises a line-trouble-detect part which samples data of the secondary channel, by multipoint sampling, to obtain the secondary data and detects the number of inversion points in the descrambled secondary channel data per unit time period. The line-trouble-detect part outputs a line-trouble signal which indicates that there is a trouble on the line if the number of detected inversion points is more than a predetermined number.