FPGA PAM-3 Signal Decoding for Automotive Ethernet

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Solution Overview

Problem

The challenge in automotive communication networks, particularly with the 100BASE-T1 Ethernet standard, is the difficulty in probing and decoding PAM-3 signals due to full duplex transmission, which results in overlaid signals that are noisy and require extensive signal processing for reconstruction.

Innovation Solution

A system comprising a directional coupler, DVGAs, ADCs, and an FPGA module for separating, amplifying, converting, and processing PAM-3 signals, including DC correction, spike filtering, edge detection, and sampling point calculation to generate accurate PAM-3 symbols.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If full duplex transmission is used between master and slave ECUs, then data throughput is improved, but signal probing and decoding becomes difficult due to overlaid signals

Engineering Contradiction:

Improvedata throughputVSAvoidsignal probing and decoding

Core Design Contradiction:

ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent segments the overlaid full-duplex signal into separate master-to-slave and slave-to-master signal components using directional couplers. Each directional coupler isolates a specific signal direction, allowing independent decoding of PAM-3 symbols without interference from the opposite direction transmission.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces directional couplers as intermediary devices between the communication line and the decoding system. These couplers act as mediators that extract and separate the bidirectional signals, enabling measurement and analysis without disrupting the full-duplex communication.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Difficulty of detecting and measuring

If directional couplers are used to separate overlaid signals, then signal separation is achieved, but the output signals become noisy requiring extensive signal processing

Engineering Contradiction:

Improvesignal separationVSAvoidsignal quality

Core Design Contradiction:

Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The patent applies preliminary signal processing operations including DC correction to remove baseline drift, spike filtering to eliminate impulsive noise, and edge detection to identify valid transitions before PAM-3 symbol decoding. These preprocessing steps clean the noisy signals from directional couplers, improving decoding reliability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the decoded PAM-3 symbols are used to validate and refine the signal processing. The system continuously monitors signal quality and adjusts processing parameters to maintain accurate decoding despite noise variations.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11405248B2FPGA based system for decoding PAM-3 signals

Publication Date: 2022.08.02 PRODIGY TECHNOVATIONS PVT LTD

AI summary

An FPGA based system for decoding PAM-3 signals is disclosed, wherein the system comprises a directional coupler for separating 100BASE-T1 and 1000BASE-T1 master and slave signals, DVGAs for amplifying the master and slave signals, ADCs for sampling the amplified signals, and a FPGA module, wherein the FPGA module is configured for decoding the PAM-3 symbols, in real-time, from oversampled ADCs data using fully pipelined Register Transfer Level (RTL) architecture.