N-tap Equalization Filter for High-Speed Signal Ringing
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Solution Overview
Problem
High-speed data communication channels experience significant ringing and intersymbol interference due to jitter caused by pulse reflections, which degrade signal quality and limit data transmission rates in fully buffered dual in-line memory module (FB-DIMM) architectures.
Innovation Solution
An n-tap equalization filter is initialized with taps associated with jitter pulses, each occurring at a time-domain point related to the corresponding jitter pulse, and applied to subsequent signals to minimize ringing and intersymbol interference, using a finite impulse response (FIR) filter design that can include multiple taps with positive and negative coefficients to compensate for reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high speed data communication is implemented in a circuit channel, then data transmission rate is improved, but signal quality deteriorates due to noise and intersymbol interference
Solution Approach 1:
The patent applies preliminary equalization action by pre-compensating the transmitted signal with an equalization filter before it enters the channel. This preliminary action counteracts the anticipated channel distortions and reflections, thereby maintaining signal quality at high transmission rates without requiring complex post-reception processing
Solution Approach 2:
The patent implements feedback-based equalization by measuring the actual channel response through training sequences or pilot signals, then using this feedback information to adjust and optimize the equalization filter coefficients. This closed-loop approach continuously adapts to channel variations, maintaining reliable signal quality despite high-speed transmission challenges
2Productivity
If pulse signals are transmitted over the channel, then data communication is enabled, but reflections cause jitter and intersymbol interference that degrade signal quality
Solution Approach 1:
The patent converts the harmful effect of channel reflections into a beneficial solution by characterizing the reflection patterns through channel measurement and then using this knowledge to design equalization filters that actively cancel the reflected signals. The harmful reflections are transformed into predictable distortions that can be systematically compensated
Solution Approach 2:
The patent changes the temporal and amplitude parameters of the transmitted signal through equalization filtering. By adjusting the filter coefficients to match the channel impulse response, the signal parameters are modified in advance to counteract the expected reflections and jitter, thereby eliminating intersymbol interference at the receiver
3Measurement precision
If channel characteristics are measured using S-parameter representations, then channel understanding is improved, but frequency-dependent loss increases energy after the main cursor has passed
Solution Approach 1:
The patent uses the precise channel characterization from S-parameter measurements to pre-compute equalization filter coefficients that compensate for the frequency-dependent losses. This preliminary action occurs before actual data transmission, allowing the system to counteract the expected energy loss and ringing effects without requiring additional transmission power
Data Source
AI summary
A method, apparatus, and system for minimizing ringing in a high speed channel between a transmitter and a receiver in a circuit, including a component for initializing an n-tap equalization filter. The n-tap equalization filter includes numerous taps, each associated with each of numerous jitter pulses received from the transmitter at the receiver and over the channel. Many of the jitter pulses are greater than two. Further, each tap occurs at a time-domain point related to a time of a corresponding jitter pulse included within the numerous jitter pulses. Moreover, a component for applying the n-tap equalization filter to a subsequent signal sent over the channel is also included.