Multi-Port Test Instrument Calibration With Fewer Measurements
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Solution Overview
Problem
Existing calibration methods for test instruments with multiple ports require a large number of measurements to fully characterize each port, leading to inefficiency and increased complexity.
Innovation Solution
A calibration method that uses a set of calibration standards and an additional calibration standard with known properties to determine error terms of a multi-port error model, allowing for the characterization of each port with a reduced number of measurements by disentangling individual error parameters through additional measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional multi-port calibration methods (TOSM/SOLT) are used to fully characterize each port, then measurement accuracy is improved, but the number of measurements required grows rapidly with the number of ports, increasing calibration time and complexity
Solution Approach 1:
The patent introduces an additional calibration standard with known properties (signal source or signal sink) as an intermediary element. This intermediary provides reference measurements that enable the mathematical separation of coupled error terms in the multi-port error model, allowing accurate port characterization without requiring all traditional multi-port measurement combinations
Solution Approach 2:
The patent changes the calibration approach by adding a calibration standard with specifically known properties (known signal source characteristics or known signal sink characteristics). This parameter knowledge allows the system to solve for individual error parameters that would otherwise be coupled and indeterminate, reducing the total measurement requirements while maintaining accuracy
2Measurement precision
If traditional multi-port calibration methods are used to fully characterize each port, then complete error correction is achieved, but the number of measurements required grows rapidly with the number of ports, increasing device complexity
Solution Approach 1:
The additional calibration standard acts as a mediator that provides the necessary reference information to simplify the calibration procedure. By introducing this intermediary element with known properties, the complex multi-port error model can be solved with fewer measurements and less procedural complexity while maintaining complete error correction capability
Solution Approach 2:
The patent extracts the essential error characterization information by using the additional calibration standard to directly measure or determine specific error parameters. This extraction approach allows the system to obtain necessary calibration data without performing all the traditional complex multi-port measurement sequences, thereby reducing procedural complexity
Data Source
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AI summary
A calibration method of calibrating a test instrument (12) is described. The test instrument (12) comprises at least one port (14, 16), at least one signal analysis module (20), and at least one signal generator module (18). The at least one signal analysis module (20) and the at least one signal generator module (18) are each connected to the at least one port (14, 16). The calibration method comprises the steps of: - consecutively connecting a set of calibration standards to the at least one port (14, 16) and performing a calibration measurement for each calibration standard (34, 36, 38) connected, thereby obtaining a first set of measurement data; - determining, based on a multi-port error model and the first set of measurement data, a plurality of error terms of the multi-port error model, wherein at least one of the error terms comprises a product of two error parameters; - connecting an additional calibration standard (40) to the at least one port (14, 16); - performing a calibration measurement with the additional calibration standard (40) connected, thereby obtaining a second set of measurement data; and - determining the two error parameters based on the second set of measurement data. Further, a calibration system (10) is described.