Frequency Deviation Compensation with Phase Offset Correction
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Solution Overview
Problem
Digital coherent receivers face errors and potential communication interruptions due to phase offsets when compensating for frequency deviations through frequency-shifting processes, especially in ultrafast optical communication systems.
Innovation Solution
A frequency deviation compensation scheme that includes both frequency shifting to correct frequency deviations and phase offset compensation, using phase offset calculation and compensation units to adjust the phase offset to a predetermined amount, thereby preventing errors caused by phase offsets during the frequency-shifting process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency shifting is used to compensate for frequency deviation, then frequency deviation compensation is achieved, but phase offset errors occur in the signal
Solution Approach 1:
The patent introduces a phase offset compensation unit as an intermediary component that processes the signal after frequency shifting. This unit calculates and compensates for the phase offset introduced by frequency shifting, thereby maintaining communication reliability while preserving the frequency deviation compensation benefit
Solution Approach 2:
The patent implements a feedback mechanism where the phase offset is calculated based on the frequency shifting amount and then fed back to compensate the signal. The phase offset compensation unit continuously monitors and corrects the phase offset, creating a closed-loop system that maintains signal integrity
2Measurement precision
If local oscillation light frequency control is used to compensate for frequency deviation, then frequency deviation compensation is achieved, but device complexity increases due to additional control arrangements
Solution Approach 1:
The patent replaces the mechanical/optical frequency control system with a digital signal processing approach. Instead of physically controlling local oscillation light frequency, the invention uses frequency shifting and phase offset compensation in the digital domain, thereby reducing device complexity while maintaining compensation accuracy
Solution Approach 2:
The patent creates a digital model of the frequency deviation and its effects, then processes a copy of the signal through frequency shifting and phase compensation algorithms. This allows frequency deviation compensation without directly manipulating the physical optical system, reducing complexity
Data Source
AI summary
When a frequency deviation compensation amount is compensated for by use of frequency shift, a phase offset occurs between adjacent input blocks included in a plurality of input blocks as divided, with the result that an error occurs in a reconstructed bit sequence. A frequency deviation compensation system of the invention is characterized by comprising: a frequency deviation compensation means for compensating for a frequency deviation occurring in a signal by use of frequency shift; and a phase offset compensation means for compensating for a phase offset occurring, in the signal, due to the frequency shift.