Integrated Receiver Filtering and Equalization for Noise-Limited Signals

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Noise limited signaling systems face performance limitations due to noise generated by circuitry, particularly thermal and flicker noise, which can introduce inter-symbol interference and baseline wander, affecting the accuracy of signal reception.

Innovation Solution

A front-end circuit amplifies and band-limits the incoming signal using high-pass and/or bandpass filters to reduce thermal and flicker noise, while an integrator circuit integrates the signal over a symbol time to cancel random noise perturbations, and equalization techniques are applied to mitigate inter-symbol interference and baseline wander.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the receiver circuitry operates in noise limited signaling systems, then signal reception is enabled, but thermal and flicker noise generate inter-symbol interference and baseline wander, degrading reception accuracy

Engineering Contradiction:
Improvesignal reception accuracyVSAvoidnoise interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by performing baseline wander correction and noise filtering before the integration process. The receiver circuitry pre-processes the incoming signal to remove low-frequency baseline drift and thermal noise components, ensuring that the integration operation starts with a cleaned signal. This preliminary processing prevents noise accumulation during integration and maintains measurement precision in noise-limited environments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary integration process that acts as a mediator between the noisy incoming signal and the final detection. The integration operation accumulates the pre-processed signal over a defined interval, effectively averaging out random thermal noise while preserving the deterministic signal components. This intermediary integration stage separates the useful signal from the harmful noise before final decision-making.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If integration is performed over a symbol time interval, then random noise perturbations are canceled, but inter-symbol interference and baseline wander affect the integrated result

Engineering Contradiction:
Improvenoise cancellationVSAvoidinter-symbol interference
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by removing baseline wander and mitigating inter-symbol interference through pre-processing operations before integration. The receiver circuitry performs high-pass filtering or baseline correction in advance to eliminate low-frequency drift components, and applies equalization or interference cancellation techniques to remove contributions from adjacent symbols. This ensures that the integration process starts with a signal that has already been cleaned of these harmful artifacts.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts and removes the harmful components of inter-symbol interference and baseline wander from the signal before integration. By using pre-processing stages that specifically target and eliminate these interference components, the patent separates the useful signal from the harmful artifacts, allowing the integration process to focus only on accumulating the desired signal energy while ignoring the extracted interference components.

Inventive Principle:
Principle #2Taking out (Extraction)

3Power

If front-end circuitry amplifies the incoming signal, then signal strength is increased, but thermal and flicker noise are also amplified

Engineering Contradiction:
Improvesignal strengthVSAvoidamplified noise
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the amplified noise components from the signal after amplification. The receiver circuitry employs filtering operations that specifically target and eliminate thermal and flicker noise components that were amplified by the front-end. By separating and removing these harmful noise components, the patent maintains the benefit of signal amplification while eliminating the corresponding noise amplification.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary filtering and processing stage between the amplification operation and the final detection. This intermediary stage acts as a mediator that allows the amplified signal to pass through while blocking or attenuating the amplified noise components. The integration and detection operations then work with this cleaned, amplified signal, achieving both high signal strength and low noise levels.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively reduces noise-related errors, improving the accuracy of signal reception by canceling random noise and compensating for inter-symbol interference and baseline wander, thereby enhancing the performance of noise limited signaling systems.

Implementation Method 1

an integrator circuit integrates the signal over a symbol time to cancel random noise perturbations

Methodology Applied
Scientific EffectIntegration:

Implementation Method 2

A front-end circuit amplifies and band-limits (e.g., with a high-pass and/or bandpass filter) an incoming signal

Methodology Applied
Scientific EffectAmplification:

Implementation Method 3

A front-end circuit amplifies and band-limits (e.g., with a high-pass and/or bandpass filter) an incoming signal

Methodology Applied
Scientific EffectFiltering: Filter (electronic)

Data Source

PatentUS10873321B1Noise reducing receiver
Publication Date: 2020.12.22 RAMBUS INC
  • US10873321B1 patent drawing
  • US10873321B1 patent drawing
  • US10873321B1 patent drawing

AI summary

Disclosed is receiver for a noise limited system. A front-end circuit amplifies and band-limits an incoming signal. The amplification increases the signal swing but introduces both thermal and flicker noise. A low-pass band limitation reduces the thermal noise component present at frequencies above what is necessary for correctly receiving the transmitted symbols. This band limited signal is provided to the integrator circuit. The output of the integrator is equalized to reduce the effects of inter-symbol interference and then sampled. The samples are used to apply low frequency equalization (i.e., in response to long and/or unbalanced strings of symbols) to mitigate the effects of DC wander caused by mismatches between the number of symbols of each kind being received.