VSWR Measurement Interference Rejection via Circle Fitting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing RF instruments for measuring voltage standing wave ratio (Γ) are affected by unwanted interference, leading to inaccurate measurements due to varying Γ values at a fixed frequency, despite ideal conditions requiring a fixed magnitude and angle ratio.
Innovation Solution
The method involves measuring electromagnetic waves with interference components at multiple times, calculating data points on a complex plane, determining chords of a circle that fit these points, and using these chords to find the approximate center of the circle, representing the electromagnetic wave with the interference removed, thereby providing an accurate Γ measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional RF instruments measure VSWR at a fixed frequency, then the measurement should be stable and accurate under ideal conditions, but unwanted interference causes the measurement to vary with time and reduces accuracy
Solution Approach 1:
The patent converts the harmful interference signal into a beneficial tool for identification and rejection. By measuring the interference signal separately and identifying its characteristics (frequency, phase, amplitude), the system uses this previously harmful information to calculate correction values that eliminate the interference from the final VSWR measurement, thereby transforming the interference from a detrimental factor into a useful reference for accurate measurement.
Solution Approach 2:
The patent introduces an intermediary correction signal that mediates between the original measurement and the final result. This correction signal, derived from the interference measurement, is combined with the original VSWR measurement through mathematical operations (multiplication and addition) to produce the interference-free VSWR value, effectively filtering out the harmful interference component.
2Device complexity
If the measurement system is simplified to reduce complexity, then the device becomes easier to operate and manufacture, but the ability to reject interference and provide accurate measurements is compromised
Solution Approach 1:
The patent segments the measurement process into distinct functional components: a first measurement path for acquiring the original VSWR signal, a second measurement path for acquiring the interference signal, a processing unit for calculating correction values based on the interference characteristics, and a combination unit for producing the final corrected measurement. This segmentation allows each component to perform its specific function efficiently while maintaining overall system simplicity and effectiveness in interference rejection.
Data Source
AI summary
A method and apparatus for measuring electrical signals measures an electromagnetic wave having an interference component at a center frequency and at multiple times to obtain data points. The positions of the data points on a complex plane are calculated. Chords of a circle on the complex plane, wherein the chords passing between pairs of the data points, and the circle fit to the data points are calculated. The chords are used to determine an approximate center of the circle wherein the position of the approximate center of the circle on the complex plane represents the electromagnetic wave with the interference component removed. An indication of the measured electromagnetic wave having the interference component removed is output from the apparatus.