Invention Grant
- Patent Title: Optical multilevel signal pre-equalization circuit, optical multilevel signal pre-equalization transmitter, and polarization-multiplexed pre-equalization transmitter
- Patent Title (中): 光学多电平信号预均衡电路,光学多电平信号预均衡发射机和偏振复用预均衡发射机
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Application No.: US13777253Application Date: 2013-02-26
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Publication No.: US09178617B2Publication Date: 2015-11-03
- Inventor: Nobuhiko Kikuchi
- Applicant: HITACHI, LTD.
- Applicant Address: JP Tokyo
- Assignee: HITACHI, LTD.
- Current Assignee: HITACHI, LTD.
- Current Assignee Address: JP Tokyo
- Agency: Mattingly & Malur, PC
- Priority: JP2012-259883 20121128
- Main IPC: H04B10/04
- IPC: H04B10/04 ; H04B10/2513 ; H04B10/2507 ; H04B10/54

Abstract:
In order to reduce the circuit size for a chromatic dispersion pre-equalization operation, an optical multilevel signal pre-equalization circuit is provided with: (1) a plurality of look-up tables in which a string of middle codes utilizing a symmetry of a signal constellation of a multilevel code or a string of middle codes represented by polar coordinates is stored in association with a waveform response component; and (2) one or more operation circuits to which the waveform response component corresponding to a multilevel signal to be transmitted is inputted from the plurality of look-up tables, and which outputs a pre-equalized output waveform corresponding to the multilevel signal by operating the waveform response components outputted from different look-up tables.
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