Vector Network Analyzer LO Drift Removal via Error-Box Correction
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Solution Overview
Problem
Vector network analyzers face measurement errors due to local oscillator phase drift, which introduces inconsistencies in S-parameters measurements between two transmissive reciprocal devices, affecting the accuracy of radio frequency characterization.
Innovation Solution
A method to automatically remove local oscillator phase drift by quantifying the drift using error-box measurement models and wave-cascading matrices, allowing for the correction of S-parameters through transformation of the measured s-matrix, utilizing the determinants and properties of similar matrices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If VNA performs measurements of reciprocal networks, then S-parameters can be obtained, but local oscillator phase drift introduces measurement errors and inconsistencies
Solution Approach 1:
The patent implements feedback by measuring a known reciprocal network (through-line) and using the resulting S-parameters to calculate and remove LO drift effects from subsequent measurements of unknown reciprocal networks. The feedback loop closes when the corrected S-parameters are used to update the measurement model, ensuring consistent and accurate results.
Solution Approach 2:
The patent introduces an intermediary approach by using a known reciprocal network as a reference standard. This intermediary allows the system to characterize and compensate for LO drift effects without directly measuring the unknown network under test, thereby separating the drift compensation process from the actual measurement process.
2Adaptability or versatility
If LO path length changes occur between measurements, then measurement flexibility is improved, but anti-reciprocal perturbation is introduced into S-parameter data
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the measurement model based on the actual LO drift conditions. The system calculates correction factors from the known reciprocal network measurement and applies these factors to correct the S-parameter measurements, effectively compensating for the anti-reciprocal perturbation introduced by LO path length changes.
3Measurement precision
If automatic drift removal method is implemented, then measurement accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent implements self-service by enabling the VNA to automatically perform drift removal using its own internal resources. The system uses its built-in ability to measure known reciprocal networks and process S-parameter data to compensate for LO drift without requiring external equipment or manual intervention, thereby reducing overall system complexity despite the advanced correction capability.
Data Source
AI summary
Certain exemplary embodiments can provide a method, which can comprise automatically removing effects of local oscillator phase drift occurring in between two measurements of reciprocal networks as made with a vector network analyzer. The method can further comprise determining that the vector network analyzer substantially simultaneously samples all incident and reflected waves from the reciprocal networks.