Frequency error estimating apparatus and method, frequency error compensating apparatus, and optical receiver
AssigneeFujitsu Limited
InventorHisao Nakashima
Life of this patent
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Abstract
Provided is a frequency error estimating apparatus used for a coherent optical receiver, which determines an amplitude of a baseband digital electrical signal converted from a received light signal modulated with a phase and amplitude shift keying, determines, with respect to each determined amplitude, a modulated phase component of the baseband digital electrical signal based on phase noise estimation values and frequency error estimation values of N previous symbols (N is a positive integer), and calculates a frequency error based on an inter-symbol phase difference of a signal obtained by cancelling the modulated phase component from the baseband digital electrical signal.
Claims7
A frequency error estimating apparatus used for a coherent optical receiver, comprising:
- an amplitude determiner configured to determine an amplitude of a baseband digital electrical signal converted from a received light signal modulated with a phase and amplitude shift keying;
- an amplitude directed phase determiner configured to determine, with respect to each amplitude determined by the amplitude determiner, a modulated phase component of a signal obtained by cancelling phase noise estimation values and frequency error estimation values of N previous symbols (N is a positive integer) from the baseband digital electrical signal;
- and
- a frequency error calculator configured to calculate a frequency error based on an inter-symbol phase difference of a signal obtained by cancelling the modulated phase component from the baseband digital electrical signal.
A frequency error estimating method in a coherent optical receiver, comprising:
- determining an amplitude of a baseband digital electrical signal converted from a received light signal modulated with a phase and amplitude shift keying;
- determining, with respect to each determined amplitude, a modulated phase component of the baseband digital electrical signal;
- and
- calculating a frequency error based on an inter-symbol phase difference of a signal obtained by cancelling the modulated phase component from the baseband digital electrical signal.
Dependencies are inferred from the claim text.