Circuit Simulation for Automated Measurement Uncertainty Calculation

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Solution Overview

Problem

High-frequency test systems face uncertainties due to impedance mismatches, temperature stability, aging, noise, and instrument accuracy, requiring manual metrological calculations that are time-consuming and labor-intensive, especially when system configurations change.

Innovation Solution

A model of the test system is developed and simulated using a circuit simulator, varying uncertainty terms within a probability distribution to generate a statistical distribution of test results, allowing for automated calculation of measurement uncertainties without manual derivation of equations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual metrological calculations are used to calculate measurement uncertainties, then the calculation accuracy can be ensured, but the time consumption and labor intensity increase significantly

Engineering Contradiction:
Improvemeasurement uncertainty calculation accuracyVSAvoidtime for uncertainty calculation
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces manual metrological calculations with automated computer-based simulations. The measurement uncertainty calculation process is transformed from a manual analytical method to an automated computational method using Monte Carlo simulations and circuit simulators, eliminating the need for highly trained metrologists while maintaining calculation accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates virtual models (copies) of the physical test system including DUT, test instruments, and interconnecting components. These simulated representations allow uncertainty calculations to be performed on digital models rather than requiring physical measurement and manual computation, significantly reducing time while preserving accuracy.

Inventive Principle:
Principle #26Copying

2Measurement precision

If manual metrological analysis is performed to develop uncertainty calculations, then the uncertainty equations can be accurately derived, but the process requires highly trained metrologists and takes several days

Engineering Contradiction:
Improveuncertainty equation accuracyVSAvoidcomplexity of uncertainty calculation process
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent enables the test system to perform its own uncertainty analysis through automated simulations. The computer automatically runs Monte Carlo simulations, varies input parameters according to their probability distributions, and computes output uncertainties without requiring external metrological expertise, making the system self-analyzing.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent transforms the uncertainty calculation from solving complex analytical equations to performing parameter variations in simulations. By changing the approach from mathematical derivation to computational experimentation with varied parameters, the process becomes automated while maintaining accuracy.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the topography of the test system is changed, then the test system can be adapted to different configurations, but the uncertainty calculations must be re-validated and changed

Engineering Contradiction:
Improvetest system configuration flexibilityVSAvoidtime for recalculating uncertainties
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent makes the uncertainty calculation system dynamic and adaptive to configuration changes. When the test system topology changes, the computer automatically updates the simulation model and re-runs the Monte Carlo analyses without requiring manual re-derivation of uncertainty equations, allowing rapid adaptation to new configurations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent creates a universal automated uncertainty analysis framework that can handle multiple test system configurations through a single simulation-based approach. The same computer-implemented method works across different DUTs, test instruments, and interconnections, eliminating the need for configuration-specific manual calculations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Measurement precision

If comprehensive uncertainty analysis is performed on all system components, then the measurement uncertainty can be accurately characterized, but the calculation complexity increases

Engineering Contradiction:
Improvecompleteness of uncertainty characterizationVSAvoidcomplexity of uncertainty calculation system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the test system into discrete segments (DUT, test instruments, interconnecting components) that can be independently modeled and simulated. Each component's uncertainty contributions are analyzed separately through individual parameter variations, then combined in the overall Monte Carlo simulation to provide comprehensive uncertainty characterization.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS7848911B2Method of determining measurement uncertainties using circuit simulation
Publication Date: 2010.12.07 KEYSIGHT TECHNOLOGIES INC
  • US7848911B2 patent drawing
  • US7848911B2 patent drawing
  • US7848911B2 patent drawing

AI summary

A method of determining a measurement uncertainty of a test system uses a test system model having a plurality of uncertainty terms entered into a simulator. The test system model is run on the simulator a sufficient number of iterations while randomly varying each of a first portion of the plurality of uncertainty terms within probability distributions to produce a statistically significant number of results of a selected parameter. The results are evaluated to determine a measurement uncertainty of the selected parameter.