Vector Network Analyzer Phase Offset Control via Frequency Tuning
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Solution Overview
Problem
Existing measuring devices face challenges in generating excitation signals with a fixed, non-fluctuating phase difference, which is essential for accurate network analysis, particularly in differential and common modes, due to the complexity and cost of using vector modulators and common synthesizers.
Innovation Solution
A measuring device with separate signal generators for each port, allowing for independent frequency adjustment to maintain a fixed phase relationship, with phase measurements at internal points and calibration to ensure the target phase offset is achieved at reference points, reducing the need for expensive vector modulators and complex phase compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a common synthesizer with vector modulators is used to generate excitation signals, then phase difference compensation can be achieved, but device complexity and cost increase significantly
Solution Approach 1:
The patent divides the signal generation system into separate signal sources for each port rather than using a single common synthesizer. Each signal generator operates independently, eliminating the need for complex vector modulators and phase compensation circuits while maintaining stable phase relationships through direct digital synthesis techniques.
Solution Approach 2:
The patent replaces expensive vector modulators with more economical signal generation approaches using direct digital synthesis and software-controlled frequency adjustment. This substitution reduces hardware complexity and cost while achieving the same measurement precision for phase difference stability.
2Measurement precision
If vector modulators are used for phase compensation, then excitation signals with fixed phase difference can be generated, but operational complexity and cost increase
Solution Approach 1:
The patent implements a feedback mechanism where the control device continuously monitors the phase difference between excitation signals and automatically adjusts the frequency of individual signal generators to maintain the target phase relationship. This closed-loop control eliminates manual calibration and simplifies operation while ensuring measurement precision.
Solution Approach 2:
The system performs automatic phase calibration and maintenance without requiring manual intervention. The control device autonomously detects phase deviations and adjusts signal generator frequencies to correct them, making the system self-regulating and easier to operate while maintaining high measurement precision.
3Device complexity
If separate signal generators are used for each port, then device complexity is reduced, but phase relationship stability becomes more challenging to maintain
Solution Approach 1:
The patent maintains phase relationship stability by dynamically adjusting the frequency parameter of individual signal generators based on real-time phase difference measurements. This frequency tuning capability allows separate signal generators to work together in synchronization, ensuring reliable phase relationships despite their independent operation.
Solution Approach 2:
The system transitions from static frequency settings to dynamic frequency adjustment, where signal generator frequencies are continuously adapted to maintain the target phase relationship. This dynamic control ensures reliability of phase relationships while keeping the overall system structure simple and modular.
Data Source
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AI summary
A method for operating a measuring device, particularly a vectorial network analyzer, which can be connected to an object to be measured via at least two gates, comprising a number of excitation units each assigned to a gate, each excitation unit having a signal generator with which the assigned gate can be subjected to the action of an excitation signal. The inventive method comprises the following steps: measuring the actual phase offset (?factual) between the excitation signals, which are output on the gates, at measuring points, and; changing the frequency of at least one of the two signal generators during a correction time interval (Tcorr) so that a predetermined set phase offset (?fset) is obtained at reference points between the excitation signals output on the gates.