Oscilloscope Probe Characterization and Correction Method
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Solution Overview
Problem
Characterizing and correcting the input impedances and responses of voltage and current probes, as well as the transmitted response of cables, is a complex and time-consuming process that typically requires specialized equipment like Vector Network Analyzers (VNAs) and external circuit simulators, which not all users have access to.
Innovation Solution
A method involving measuring output signals with and without the probe or cable connected, using a signal generator and oscilloscope to characterize and correct responses, allowing for the determination of input impedances and transfer functions without the need for VNAs or additional equipment, by applying correction filters based on ideal frequency responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If VNA and external circuit simulators are used to characterize probes and cables, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the characterization function from complex external equipment (VNA) and implements it within the oscilloscope itself. The oscilloscope measures probe and cable responses directly and generates correction filters internally, eliminating the need for separate VNA and simulation equipment while maintaining characterization accuracy.
Solution Approach 2:
The oscilloscope is designed to perform multiple functions: it acts as both the measurement instrument and the characterization tool. The same oscilloscope that measures signals can also characterize probes and cables by measuring their responses and generating correction filters, consolidating multiple specialized devices into one universal instrument.
2Measurement precision
If VNA and external circuit simulators are used to characterize probes and cables, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent combines the characterization process with the measurement process. By measuring probe and cable responses directly during normal operation and generating correction filters on-the-fly, the system eliminates separate characterization steps, reducing total time while maintaining accuracy through integrated processing.
Solution Approach 2:
The system performs preliminary measurements of probe and cable responses to establish baseline characteristics. These preliminary measurements enable the generation of correction filters that can be applied to subsequent measurements, streamlining the overall process and reducing repeated characterization time.
3Device complexity
If simple measurement equipment is used to characterize probes and cables, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent replaces complex external measurement systems with a software-based characterization approach within the oscilloscope. By using digital signal processing and mathematical models to generate correction filters, the system achieves high precision without requiring additional complex hardware equipment.
Solution Approach 2:
The system changes the approach from physical equipment complexity to computational precision. By using advanced algorithms and mathematical models within the oscilloscope's processing capabilities, the system achieves accurate characterization and correction without requiring complex external measurement equipment.
4Measurement precision
If comprehensive characterization procedures are implemented, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The oscilloscope performs self-characterization by automatically measuring probe and cable responses and generating correction filters without requiring external equipment or complex user setup. The system serves itself by using its own measurement capabilities to characterize its accessories, greatly simplifying the user experience while maintaining accuracy.
Solution Approach 2:
The patent introduces an intermediary processing layer within the oscilloscope that automatically handles the complex characterization mathematics. This intermediary layer translates simple user actions (connecting the probe/cable) into comprehensive characterization results, shielding users from complexity while achieving precise measurements.
Data Source
AI summary
Responses of voltage and current probes are characterized or corrected. A voltage probe method includes measuring output of the voltage probe and a first output of a through, in response to an input signal applied to the through, with the voltage probe connected, measuring a second output of the through with the voltage probe disconnected, and characterizing the response of the voltage probe using the output of the voltage probe and the first and/or second outputs. A current probe method includes measuring output current of the current probe and first output current of a through, in response to an input signal applied to the through with the current probe connected in series, measuring second output current of the through with the current probe disconnected, and characterizing the response of the current probe using the output current of the current probe and the first and/or second output currents of the through.