Scattering Parameter Measurement Phase Coherence Compensation
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Solution Overview
Problem
Existing methods for determining scattering parameters of frequency-converting devices under test face challenges due to system errors, particularly phase inaccuracy, which are difficult to compensate accurately, especially when using phase references that restrict frequency ranges and require complex and costly setups.
Innovation Solution
A method and system for system-error compensation that initializes the phases of excitation and local oscillator signals in a phase-coherent manner, using direct-digital synthesis or numerically controlled oscillators, to ensure identical phases across all ports, allowing for accurate compensation of amplitude and phase uncertainties in system-error-adjusted signals, thereby determining scattering parameters with high accuracy at lower costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase references or phase standards are used to determine the phase component of unknown complex factors, then measurement accuracy is improved, but device complexity and measurement costs increase
Solution Approach 1:
The patent uses signal copying and processing to determine phase components. Instead of using physical phase references or standards, the method copies the excitation signal through the measurement system and processes it to extract phase information mathematically, thereby avoiding the need for complex physical reference devices
Solution Approach 2:
The patent replaces the mechanical/physical phase reference system with a signal processing approach. By using mathematical operations on measured signals rather than physical phase standards, the method eliminates complex hardware while maintaining measurement accuracy
2Measurement precision
If phase references are used for calibration, then phase accuracy is improved, but the frequency range is restricted
Solution Approach 1:
The patent changes the approach from using fixed frequency phase references to a method that calculates phase components across different frequencies through signal processing. This allows the system to adapt to various frequencies without being constrained by the limitations of physical phase reference devices
3Ease of operation
If conventional error models are used for system error compensation, then measurement process is simplified, but phase inaccuracy remains difficult to compensate
Solution Approach 1:
The patent introduces a feedback mechanism where the measured signals are processed to determine unknown complex factors, and these factors are then used to compensate for phase inaccuracies in the measurement system. This closed-loop approach improves phase accuracy while maintaining operational simplicity
Solution Approach 2:
The patent performs preliminary determination of unknown complex factors from measured signals before using them to compensate for system errors. This preliminary action allows the system to correct phase inaccuracies without complicating the overall measurement process
Data Source
AI summary
A system for determining scattering parameters of a frequency-converting device under test using a network analyzer determines the system errors which occur between the individual ports (1, 2) of the frequency-converting device under test (3) and the ports (4, 5) of the network analyzer (6) connected to the ports (1, 2) of the frequency-converting device under test (3) and measures the system-error-containing signals incoming and outgoing in each case at the individual ports (1, 2) of the frequency-converting device under test (3). Following this, system-error-adjusted signals incoming and outgoing in each case at the individual ports (1, 2) of the frequency-converting device under test (3) are determined by weighting the system-error-containing signals incoming and outgoing in each case at the individual ports (1, 2) of the frequency-converting device under test (3) with the associated, determined system errors, and the scattering parameters of the frequency-converting device under test (3) are determined from the system-error-adjusted signals incoming and outgoing in each case at the individual ports (1, 2) of the frequency-converting device under test (3). The phase of the signal to be measured exciting, in each case, a port (1, 2) of the frequency-converting device under test (3) is initialized in an identical manner in every measurement.