Cross-Connected Quadrature Equalization for High-Rate Receivers
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Solution Overview
Problem
Optical transmission systems face challenges in achieving optimal equalization of quadrature-modulated signals at high data rates due to limitations in processing speed of electronic components, restricting the accuracy of multi-level modulation methods.
Innovation Solution
A cross-connected arrangement of equalizers is used, where the in-phase and quadrature signals are mutually considered for equalization, allowing for repeated stages of equalization to enhance the accuracy of signal determination, particularly in optical transmission systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional separate equalization of in-phase and quadrature signals is used, then device complexity is reduced, but measurement precision and reliability deteriorate due to inability to achieve optimal equalization at high data rates
Solution Approach 1:
The patent merges the separate equalization processes for in-phase and quadrature signals into a unified cross-connected equalization structure. The in-phase equalizer and quadrature equalizer are interconnected such that the output of each feeds into the other, enabling joint equalization that improves signal determination accuracy while managing device complexity through structured integration.
2Productivity
If processing speed is increased to handle high data rates, then productivity improves, but device complexity increases due to electronic component limitations
Solution Approach 1:
The equalization process is segmented into distinct in-phase and quadrature equalization paths that can be independently optimized and implemented. This segmentation allows the system to handle high data rates by dividing the processing task into manageable segments while maintaining overall system performance through their cross-connected integration.
Data Source
AI summary
A receiver is provided for a quadrature-modulated signal, which can be divided into an inphase signal and a quadrature signal. The inphase signal is fed to first and third equalizers, and the quadrature signal is fed to second and fourth equalizers, wherein the first and second equalizers each perform a first equalization of the respective signal. An output of the first equalizer is connected to a second input of the fourth equalizer, which, by means of a second equalization of the quadrature signal, transmits an equalized quadrature signal as a function of the previously fed equalized inphase signal of the first equalizer. An output of the second equalizer is connected to the second input of the third equalizer, which, through a second equalization of the inphase signal, transmits an equalized inphase signal as a function of the previously fed equalized quadrature signal of the second equalizer.