Telefonaktiebolaget Lm Ericsson (publ)

Anders Djupsj&ouml;backa

Mehran Mokhtari

Peeter Ellervee

The present invention relates to the encoding and decoding. respectively, of serial data, using block codes. Encoding of a serial bit stream of input data in groups of N bits, so-called words (O), to serial output data in groups of 2N bits, so-called code words (KO), is preferably carried out by a logic circuit in a manner such that N of the 2N bits in the code words (KO) are comprised of the N bits input data, unchanged or inverted, and remaining bits in the code words (KO) are determined so that, seen statistically, the code words (KO) will include approximately as many zeros as ones, such that each code word (KO) will be unique for each word (O), and such that at least one of the code words (KO) will remain unique even in bit stream shifting processes. Decoding includes further encoding in a similar logic circuit and comparison of the incoming code words with the code words encoded in the logic circuit, in a predetermined manner.

Method and apparatus for encoding/decoding N-bit data into 2N-bit codewords

The present invention relates to an optical duobinary transmitter system and method using optical intensity modulation. The system comprises an input terminal ( ) arranged to receive a first binary signal, a driving circuit ( ) connected to the input terminal and arranged to convert the first binary signal into a second and a third binary signal, a double electrode optical modulator ( ) connected to the driving circuit in such a way that its upper and lower electrode may be driven by said second and third binary signal, respectively, said modulator being further arranged to modulate the amplitude and phase of an optical carrier according to the binary driving signals so as to provide an optical duobinary signal corresponding to said first binary signal and with a predetermined negative modulation chirp parameter, and an output terminal ( ) connected to the optical modulator and arranged to feed an optical transmission line with the modulated optical duobinary signal. The modulator may alternatively be arranged to be driven by quasi-ternary signals.

Optical transmitter system and method

The present invention relates to the encoding and decoding respectively of serial data, using block codes. Encoding of a serial bit stream of input data in groups of N bits, so-called words (O), to serial output data in groups of 2N bits, so-called code words (KO), is preferably carried out by a logic circuit in a manner such that N of the 2N bits in the code words (KO) are comprised of the N bits input data, unchanged or inverted, and remaining bits in the code words (KO) are determined so that, seen statistically, the code words (KO) will include approximately as many zeros as ones, such that each code word (KO) will be unique for each word (O), and such that at least one of the code words (KO) will remain unique even in bit stream shifting processes. Decoding includes further encoding in a similar logic circuit and comparison of the incoming code words with the code words encoded in the logic circuit, in a predetermined manner.

Growing community of inventors

Solna, Sweden

Anders Djupsjöbacka

Growing community of inventors

Solna, Sweden

Anders Djupsj&ouml;backa

Anders Djupsjöbacka