Transmitter Filter Tap Tuning via Receiver Equalizer Feedback
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Solution Overview
Problem
Existing interconnection systems fail to fully consider complete channel characteristics when setting and tuning filter taps of transmitter filters, leading to signal distortion and increased bit error rates due to pre-cursor and post-cursor effects.
Innovation Solution
A method and processing module that perform pattern comparison and voting to adjust pre-tap and post-tap settings of the transmitter filter based on channel characteristics, using a combination of comparators, a voting module, and an accumulator to increment or decrement taps based on accumulation results and equalizer tap signs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If filter taps are adjusted based on incomplete channel characteristics, then device complexity is reduced, but signal distortion and bit error rate increase
Solution Approach 1:
The patent implements a feedback mechanism where the receiver equalizer tap settings are fed back to the transmitter filter tap adjustment module. This allows the transmitter to adjust its filter taps based on actual channel characteristics observed at the receiver, creating a closed-loop system that improves signal quality without requiring complex direct measurement at the transmitter side.
Solution Approach 2:
The patent uses the receiver equalizer tap settings as an intermediary to convey channel characteristics back to the transmitter. Instead of directly measuring complex channel characteristics at the transmitter, the system uses the equalizer taps (which already reflect channel effects) as a mediator to guide filter tap adjustments, simplifying the overall system complexity while maintaining reliability.
2Reliability
If complete channel characteristics are considered in filter tap settings, then signal distortion is reduced, but device complexity increases
Solution Approach 1:
The patent extracts only the essential channel characteristic information needed for filter tap adjustment, specifically using the equalizer tap settings as a simplified representation of complete channel characteristics. This extraction approach allows the system to capture the necessary information (pre-cursor and post-cursor effects) without processing the full complexity of channel characteristics.
Solution Approach 2:
The patent changes the parameter used for tap adjustment from direct channel impulse response measurements to equalizer tap settings. This parameter substitution simplifies the adjustment mechanism while maintaining the ability to compensate for channel effects, as the equalizer taps already encode the necessary channel characteristic information.
3Productivity
If pre-tap tuning is performed without pattern comparison and voting, then processing speed is reduced, but device complexity decreases
Solution Approach 1:
The patent implements periodic pattern comparison and voting operations during the tap tuning process. By performing comparisons over multiple patterns and using a voting mechanism, the system achieves robust tap selection that is resistant to noise and interference, improving the reliability of the tuning process while maintaining acceptable processing speeds through structured periodic operations.
Data Source
AI summary
A method and associated processing module for an interconnection system, providing a pre-tap tuning directing and a post-tap tuning directing. The interconnection system includes a transmitter filter and a receiver equalizer; the transmitter filter performs filtering according to a pre-tap and a post-tap, and the receiver equalizer performs equalization according to an equalizer tap. The pre-tap tuning directing includes: forming an indicative pattern with a plurality of data samples and a transition sample from an equalized signal, comparing if the indicative pattern matches predetermined pattern(s), and accordingly directing whether the pre-tap is incremented/decremented. The post-tap tuning directing selects whether the post-tap is incremented/decremented according to a positive/negative sign of the equalizer tap.