Equalization Circuit for Waveform Distortion Compensation
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Solution Overview
Problem
Existing techniques face challenges in accurately compensating for waveform distortions with semi-fixed characteristics and those varying at high speed, leading to decreased individual accuracy in compensation.
Innovation Solution
An equalization processing circuit that includes frequency domain and time domain equalization means, along with detection and control units to separate and compensate for quasi-static and dynamic waveform distortions, using calculated coefficients for precise correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If waveform distortion compensation is performed in series for both semi-fixed characteristics and high-speed varying characteristics, then both types of distortions can be compensated, but the individual accuracy of compensation decreases
Solution Approach 1:
The patent segments the waveform distortion compensation into two independent parallel paths: one for semi-fixed characteristics (using decision-directed equalization) and another for high-speed varying characteristics (using blind equalization). This segmentation allows each path to specialize in its specific distortion type, maintaining high individual accuracy while providing comprehensive compensation coverage for both distortion types simultaneously.
2Measurement precision
If digital signal processing is used to compensate for frequency and phase offset or polarization fluctuation, then compensation accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent segments the digital signal processing into distinct functional blocks: frequency/phase offset compensation module and polarization fluctuation compensation module. Each module handles specific compensation tasks independently, which improves accuracy for each parameter while organizing complexity into manageable, specialized units rather than a monolithic complex processor.
Solution Approach 2:
The patent employs adaptive digital signal processing where the compensation parameters are dynamically adjusted based on real-time signal conditions. The system continuously tracks and compensates for frequency drift, phase offset, and polarization changes, transforming static compensation into a dynamic process that maintains high accuracy without requiring overly complex fixed-structure processors.
3Speed
If high-speed A/D converter is used for signal processing, then processing speed is improved, but device complexity and cost increase
Solution Approach 1:
The patent utilizes high-speed A/D converters to capture optical signals at high sampling rates, enabling real-time digital signal processing. The dynamic equalization algorithms adapt to signal conditions at these high speeds, maintaining processing speed while managing complexity through efficient algorithm implementation and specialized hardware architecture designed for high-speed operation.
Data Source
AI summary
It is made possible to compensate for a waveform distortion having semi-fixed characteristics and a waveform distortion varying at high speed with a high degree of accuracy.An equalization processing circuit according to an exemplary aspect of the present invention includes frequency domain equalization means for performing a frequency domain equalization on a digital signal using an inputted frequency domain equalization coefficient; time domain equalization means for performing a time domain equalization on a digital signal using an inputted time domain equalization coefficient; waveform distortion detection means for detecting a dynamic waveform distortion and a quasi-static waveform distortion of an equalized digital signal on which the equalization to be performed; frequency domain equalization coefficient control means for calculating a frequency domain equalization coefficient based on a quasi-static waveform distortion; and time domain equalization coefficient control means for calculating a time domain equalization coefficient based on a dynamic waveform distortion.