Quadrature RF Measurement Circuit for Accurate Phase and Gain
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Solution Overview
Problem
Existing measurement apparatuses for RF signal processing circuits face challenges in accurately determining phase shift and gain due to production tolerances and imperfections in components like mixers and phase splitters, leading to measurement errors.
Innovation Solution
A measurement apparatus comprising a double-quadrature mixer and multiplexers that generate and process quadrature signals to calculate phase shift and gain, using specific configurations and averaging techniques to mitigate errors caused by component imbalances and phase errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement apparatuses are used to measure phase shift and gain in RF circuits, then the measurement process is simple, but measurement precision deteriorates due to production tolerances and component imperfections
Solution Approach 1:
The measurement apparatus segments the measurement process into distinct phases: signal splitting into quadrature components, separate processing of I and Q signals through multiplexers, and independent measurement of phase and gain parameters. This segmentation allows each component to be optimized for its specific function, improving overall measurement precision despite increased structural complexity
Solution Approach 2:
The patent introduces quadrature signals (I and Q components) as intermediary representations of the original RF signals. These intermediate signals facilitate accurate phase and gain measurements by transforming the measurement problem into a domain where component imperfections can be mathematically compensated, thereby improving measurement precision
2Manufacturing precision
If production tolerances are relaxed in manufacturing RF circuits, then manufacturing precision improves and cost decreases, but measurement precision deteriorates due to increased variability in gain and phase
Solution Approach 1:
The measurement apparatus employs feedback mechanisms where the measured phase and gain values are used to compensate for production tolerances. The system continuously monitors and adjusts for variations in component characteristics, allowing relaxed manufacturing tolerances while maintaining measurement precision through mathematical compensation of the measured deviations
Solution Approach 2:
The patent transforms the measurement parameters from direct RF signal analysis to quadrature domain representations (I and Q components). This parameter transformation enables the system to measure and compensate for production tolerances in gain and phase, allowing relaxed manufacturing precision while maintaining accurate measurements through mathematical processing of the transformed parameters
3Measurement precision
If component imbalances and phase errors in mixers and phase splitters are reduced, then measurement precision improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent converts the harmful effect of component imbalances and phase errors into beneficial measurement information. By deliberately measuring these imperfections through the quadrature signal processing architecture, the system calculates compensation factors that eliminate the measurement errors, thereby improving measurement precision without requiring expensive high-precision components
Data Source
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AI summary
A measurement apparatus comprising a first terminal to receive an input signal of a circuit under test; a second terminal to receive an output signal of the circuit under test. A first and second phase splitter configured to generate a first and second phase signal, I1 and I2, and a first and second quadrature signal, Q1 and Q2. A first and second multiplexer, each coupled to the first terminal and the second terminal and configured to alternately pass the input and output signals of the circuit under test to the inputs of the first and second phase splitters. A double-quadrature mixer having four inputs configured to receive I1, Q1, I2, and Q2, and an output. A calculation unit to determine one or both of a phase shift of the circuit under test and/or a gain of the circuit under test based on the output of the double-quadrature mixer.