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:
Jun. 21, 1994
Filed:
May. 18, 1993
Benjamin T Speiser, Oakland, CA (US);
3COM Corporation, Santa Clara, CA (US);
Abstract
An FDDI transmitting apparatus employs a scrambler to scramble input NRZ data which in turn is input to an NRZI-to-NRZ pre-encoder. This is in turn coupled in series with an NRZ-to-NRZI encoder to produce scrambled FDDI data for transmission whose spectral content is predistorted as a result of the scrambling to minimize spectral content peaks above about 30 MHz. The scrambling is performed according to the equation y.sub.i =x.sub.i +y.sub.i-14 +y.sub.i-15. A complementary receiving apparatus employs an NRZI-to-NRZ decoder which, according to the invention, is coupled to an NRZ-to-NRZI postdecoder. This data is thence coupled to a descrambler according to the invention to recover the original data.