Method and apparatus for controlling the spectral content of a data stream
US5323463A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 18, 1993 |
| Grant date | Jun 21, 1994 |
| Priority date | — |
| Expiry date | May 18, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/03872
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.