PWM-Based TDR Pulse Timing for Low-Cost Node Differentiation
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Solution Overview
Problem
Existing TDR implementations for node differentiation in 10Base-T1S systems are too complex and expensive due to high sampling rates and memory transfer speeds, making them unsuitable for cost-effective node differentiation.
Innovation Solution
Employing fine edge placement pulse width modulation (PWM) to generate excitation and sampling pulses, allowing precise control over pulse edges, and using internal or external sampling circuits to capture reflections without requiring external high-speed analog-to-digital converters or specialized components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional TDR implementations use high sampling rates and fast memory transfer speeds to achieve precise node differentiation, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent replaces complex high-speed digital sampling systems with a pulse width modulation-based measurement approach. Instead of using fast ADCs and high-speed memory transfer, the system uses PWM to generate excitation pulses and measure reflection timing through pulse width variations, substituting a simpler electronic control mechanism for complex high-speed data acquisition hardware
Solution Approach 2:
The patent changes the measurement parameter from direct voltage sampling at high speeds to pulse width modulation duty cycle measurement. By measuring the duty cycle of PWM signals that represent reflection timing, the system achieves the same node differentiation precision with lower sampling rate requirements and simpler hardware
2Measurement precision
If traditional TDR implementations use high sampling rates to achieve accurate cable fault localization, then measurement precision is improved, but cost increases due to specialized components
Solution Approach 1:
The patent uses standard, inexpensive PWM circuitry and microcontroller units that are widely available and cost-effective, replacing expensive specialized TDR hardware. The approach uses ordinary digital components to achieve precise fault localization, making the system economically viable for mass production in automotive and industrial applications
Solution Approach 2:
The patent substitutes expensive high-speed ADCs and specialized sampling hardware with affordable PWM-based timing measurement circuits. By using pulse width modulation and duty cycle measurement instead of direct high-speed voltage sampling, the system achieves the same measurement precision with significantly reduced component costs
3Ease of operation
If PWM is used to generate excitation and sampling pulses with offset timing, then ease of operation is improved, but device complexity increases due to synchronization requirements
Solution Approach 1:
The patent combines the generation of excitation pulses and sampling pulses into a single PWM circuit or synchronized PWM modules. By using a common PWM generator for both pulse types with programmable duty cycles and timing offsets, the system simplifies the control architecture and reduces the number of separate timing generation circuits required
Solution Approach 2:
The patent employs a universal PWM circuit that can generate both excitation and sampling pulses with different timing characteristics. The same PWM hardware is used for multiple functions by programming different duty cycles and phase offsets, eliminating the need for separate dedicated circuits for each pulse type and reducing overall system complexity
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
Achieves a cost-effective TDR solution with high sampling rates and improved cable length resolution, enabling precise localization and identification of nodes, fault detection, and other applications like level sensing and moisture monitoring without the need for expensive equipment.
Implementation Method 1
a first pulse width modulation (PWM) circuit to generate an excitation pulse and output the excitation pulse to a node of a transmission medium
Implementation Method 2
The signal may be indicative of a reflection of the excitation pulse at the node of the transmission medium
Implementation Method 3
a sampling circuit to cause to the sampling circuit to record a signal. The sampling pulse may be offset from the excitation pulse by a time interval
Data Source
AI summary
A system and method for time domain reflectometry (TDR) using fine edge placement pulse width modulation (PWM) is disclosed. The system may include a first pulse width modulation (PWM) circuit. The first PWM circuit may be to generate an excitation pulse and output the excitation pulse to a node of a transmission medium. The system may also include a second PWM circuit. The second PWM circuit may be to generate a sampling pulse and output the sampling pulse a sampling circuit to cause to the sampling circuit to record a signal. The sampling pulse may be offset from the excitation pulse by a time interval. The signal may be indicative of a reflection of the excitation pulse at the node of the transmission medium.