Parallel FFE-DFE Filter Structure for Comparable Oscilloscope Signals
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Solution Overview
Problem
Existing test and measurement instruments, such as oscilloscopes, face challenges in comparing output signals from decision feedback equalizer (DFE) and feed forward equalizer (FFE) circuits due to their different equalization characteristics, leading to inconsistencies in signal processing.
Innovation Solution
A parallel filter structure is introduced, comprising both FFE and DFE circuits that process the same time and value discrete input signal in parallel, with communicative connections allowing for adaptive parameter setting based on output signals to minimize a cost function, ensuring equivalent equalizing functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If FFE and DFE circuits are used separately for different functionalities, then each circuit can be optimized for its specific function, but the output signals become incomparable due to different equalization characteristics
Solution Approach 1:
The patent applies parameter changes by adjusting the filter coefficients of the FFE circuit to match the equalization characteristics of the DFE circuit. Specifically, the FFE filter coefficients are set based on the DFE filter coefficients, ensuring that both circuits produce equivalent output signals when processing the same input, thereby enabling comparability while maintaining functional optimization
Solution Approach 2:
The patent uses copying by replicating the DFE equalization characteristics into the FFE circuit through coefficient copying. The FFE circuit is configured to copy the equalization behavior of the DFE circuit, allowing the FFE output to be a comparable representation of the same signal processing function
2Reliability
If DFE circuit is used for eye diagram functionality, then noise suppression is improved, but hardware resources increase compared to FFE circuit
Solution Approach 1:
The patent applies dynamics by enabling the test and measurement instrument to dynamically switch between using DFE for eye diagram functionality (when noise suppression is prioritized) and FFE for other functionalities (when hardware resource conservation is prioritized). The filter coefficients are adaptively configured based on the operational mode, allowing optimal performance for each specific function
Data Source
AI summary
The present disclosure relates to a parallel filter structure for processing a signal. The parallel filter structure includes a signal input configured to receive a time and value discrete input signal. The parallel filter structure includes a feed forward equalizer circuit connected with the signal input for receiving the time and value discrete input signal. The parallel filter structure includes a decision feedback equalizer circuit connected with the signal input for receiving the time and value discrete input signal. The feed forward equalizer circuit and the decision feedback equalizer circuit together form a parallel circuit. Further, an oscilloscope and a method of processing a signal are provided.