Impedance Measurement Circuit Using Time-of-Flight TDC
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Solution Overview
Problem
Current impedance measurement techniques face challenges in accurately determining the characteristics of materials under test, particularly in dynamic environments and when precise phase angle determination is required, due to limitations in phase sweep methods such as time-consuming data collection and precision errors.
Innovation Solution
The system employs a time-of-flight method using a Time-to-Digital Conversion (TDC) chip to directly measure the time between signal edges, allowing for precise computation of phase shifts and impedance or dielectric properties, thereby enhancing measurement accuracy and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase sweep methods are used to measure impedance characteristics, then measurement coverage is improved, but measurement time increases and precision decreases
Solution Approach 1:
The patent extracts only the essential measurement information (time between signal edges) rather than performing a complete phase sweep across multiple frequencies. The TDC chip directly measures the time of flight between transmitted and received signal edges, eliminating the need for time-consuming phase sweep procedures while capturing the critical impedance characterization data.
Solution Approach 2:
The patent replaces the mechanical/sequential phase sweep method with a direct electronic time measurement system. Instead of mechanically sweeping through phase angles and collecting data points, the system uses a TDC chip to electronically and directly measure the time interval between signal edges, achieving both speed and precision.
2Measurement precision
If phase sweep methods are used to measure impedance characteristics, then measurement coverage is improved, but measurement precision deteriorates
Solution Approach 1:
The patent introduces a TDC chip as an intermediary device that simplifies the measurement process. This specialized time-to-digital converter acts as a mediator between the transmitted signal and the measurement system, directly converting time-of-flight information into digital values without requiring complex phase sweep algorithms or multiple measurement channels.
Solution Approach 2:
The patent replaces the complex mechanical phase sweep system with a streamlined electronic time measurement approach. The TDC chip provides a direct electronic measurement path that eliminates the need for complex phase modulation, sweeping mechanisms, and associated control systems, thereby reducing device complexity while improving precision.
3Adaptability or versatility
If traditional impedance measurement methods are used in moving systems, then adaptability is improved, but measurement precision deteriorates due to motion effects
Solution Approach 1:
The patent uses periodic signal transmission with direct time-of-flight measurement. By transmitting periodic signals and measuring the time between corresponding edges using a TDC chip, the system achieves motion-insensitive measurements. The periodic nature allows for continuous measurement while the direct time measurement method remains unaffected by the motion of the system, maintaining precision in moving environments.
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
This approach provides improved precision and reduced cycle time for measuring phase angles, even in moving systems, ensuring consistent and accurate characterization of material properties.
Implementation Method 1
The system employs a time-of-flight method using a Time-to-Digital Conversion (TDC) chip to directly measure the time between signal edges
Data Source
AI summary
Embodiments include a system and circuit for measuring characteristics of a material under test (MUT). In some cases, the system includes a circuit having level detectors to measure the change in strength between a reference signal and a return signal passed through the MUT. The system can include a computing device to evaluate the measured signals and adjust those signals within range of the level detectors and other circuit components. Circuits can include a time-of-flight digital convertor for determining the phase shift between the reference and return signals that pass through the MUT. The measured difference in signal strength and phase can be used to compute the complex impedance or dielectric properties of the MUT. This impedance or dielectric property can be correlated with a physical property of the MUT. The system may be operated at a single frequency, or over a range of frequencies.