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:
Sep. 03, 2002
Filed:
Jan. 29, 2001
Joseph Mardell Kahn, San Carlos, CA (US);
Keangpo Ho, San Jose, CA (US);
StrataLight Communications, Inc., Campbell, CA (US);
Abstract
Methods and apparatus to transmit and receive information bits encoded in duobinary, multilevel pulse-amplitude-modulated (PAM) optical signals are described. The transmitted optical signal has a narrow optical spectrum and a low symbol rate. Information bits are encoded in a M-ary PAM symbol sequence, where M≧3. The subsequence-based encoder decomposes the PAM symbol sequence into M1 subsequences, precodes each subsequence, performs duobinary filtering on each precoded subsequence, and forms a weighted sum of the duobinary precoded subsequences. The weighted sum of duobinary precoded subsequences is lowpass filtered and modulated onto an optical electric field. The receiver processes a received optical electric field to obtain an electrical signal proportional to the received optical intensity, and performs M-ary symbol-by-symbol decisions to recover the transmitted information bits, without potential error propagation.