Signal processing apparatus, optical transmitting apparatus, optical receiving apparatus, optical transmission system, and signal processing method
AssigneeNEC Corporation
InventorsMasaki Sato, Junichi Abe
Life of this patent
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Abstract
A signal processing apparatus (10) according to the present disclosure includes: an overlap-type FFT processing unit (11) that performs FFT processing overlapping input subcarrier signals each other for each of FFT blocks, and a generation unit (12) that generates a signal which is obtained by frequency shifting the subcarrier signals that have been subjected to the FFT processing by the overlap-type FFT processing unit (11) by a frequency shift amount of a subcarrier, a phase offset that occurs between the FFT blocks overlapping each other being compensated in the signal.
Claims17
A signal processing apparatus comprising:
- a processor performing Fast Fourier Transform (FFT) processing of overlapping subcarrier signals for each of FFT blocks;
- and
- a generator generating a signal obtained by frequency shifting the subcarrier signals that have been subjected to the FFT processing by a frequency shift amount of a subcarrier, a phase offset that occurs between the FFT blocks overlapping each other being compensated in the signal,
- wherein the generator computes the phase offset that occurs in the frequency-shifted signal,
- compensates the computed phase offset for the subcarrier signals that have been subjected to the FFT processing, and
- frequency shifts, by the frequency shift amount, the subcarrier signals where the phase offset has been compensated.
An optical transmitting apparatus comprising:
- a signal processor processing an input digital signal;
- and
- an optical transmitter optically modulating the processed signal and transmitting the optical signal that has been optically modulated to an optical transmission line, wherein
- the signal processor performs Fast Fourier Transform (FFT) processing of overlapping subcarrier signals demultiplexed from the digital signal for each of FFT blocks, and
- generates a subcarrier arrangement signal obtained by frequency shifting the subcarrier signals that have been subjected to the FFT processing by a frequency shift amount of a subcarrier, a phase offset that occurs between the FFT blocks overlapping each other being compensated in the subcarrier arrangement signal.
An optical receiving apparatus comprising:
- an optical receiver receiving a subcarrier-multiplexed optical signal from an optical transmission line and photodetecting the received optical signal;
- and
- a signal processor converting the photodetected signal into a digital signal and processing the converted digital signal, wherein
- the signal processor performs Fast Fourier Transform (FFT) processing of overlapping digital signals for each of FFT blocks, and
- generates subcarrier demultiplexing signals obtained by frequency shifting subcarrier signals included in the digital signal that has been subjected to the FFT processing by a frequency shift amount of a subcarrier, a phase offset that occurs between FFT blocks overlapping each other being compensated in the subcarrier demultiplexing signals,
- wherein the signal processor performs Inverse Fast Fourier Transform (IFFT) processing on the subcarrier demultiplexing signals, and
- multiplexes the subcarrier demultiplexing signals that have been subjected to the IFFT processing.
Dependencies are inferred from the claim text.