MRI RF Amplifier Gain-Phase Control for Load Impedance Shifts
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Solution Overview
Problem
Magnetic Resonance Imaging (MRI) apparatuses face issues with linearity in radio frequency amplifying devices due to fluctuating load impedance, leading to decreased performance in amplifying radio frequency signals.
Innovation Solution
A radio frequency amplifying device equipped with load impedance calculating circuitry and controlling circuitry that adjusts the gain and phase of input signals to maintain specified amplification factors and phases, even when load impedance deviates from a nominal value, by using adjustment value information to correct for non-linear relationships between input and output signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional radio frequency amplifying devices are used without load impedance compensation, then the device structure remains simple, but linearity decreases when load impedance fluctuates
Solution Approach 1:
The patent implements a feedback mechanism where the controlling circuitry continuously monitors the load impedance and dynamically adjusts the gain and phase of the input signal based on detected impedance variations. This closed-loop feedback system maintains linearity by compensating for load changes in real-time, resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The patent changes the operational parameters (gain and phase) of the amplifying device based on detected load impedance conditions. By dynamically adjusting these parameters through the controlling circuitry, the system maintains optimal linearity performance across varying load conditions without requiring additional hardware components, thus resolving the contradiction between reliability and device complexity.
2Reliability
If additional components like isolators or circulators are added to maintain linearity, then linearity is improved, but device complexity and cost increase
Solution Approach 1:
The patent enables the radio frequency amplifying device to self-correct linearity issues through its own controlling circuitry. The system autonomously detects load impedance changes and adjusts its operational parameters without requiring external isolators or circulators, making the device self-sufficient and avoiding additional components that would increase complexity and cost.
Solution Approach 2:
The controlling circuitry uses feedback from load impedance detection to automatically adjust gain and phase parameters, creating a self-regulating system that maintains linearity without external intervention or additional passive components, thereby resolving the contradiction between reliability and device complexity.
3Reliability
If gain and phase are adjusted dynamically based on load impedance, then linearity is maintained, but control complexity increases
Solution Approach 1:
The patent dynamically changes the gain and phase parameters based on detected load impedance conditions. The controlling circuitry processes impedance information and adjusts operational parameters in real-time, maintaining linearity through parameter optimization rather than structural complexity, thus resolving the contradiction between reliability and control complexity.
Data Source
AI summary
A radio frequency amplifying device according to an embodiment includes load impedance calculating circuitry and controlling circuitry. The load impedance calculating circuitry is configured to calculate a load impedance on the basis of information about a voltage standing wave rate and a phase on an output side of radio frequency amplifying circuitry. The controlling circuitry is configured to adjust a gain and a phase of a signal to be input to the radio frequency amplifying circuitry, in accordance with the load impedance calculated by the load impedance calculating circuitry.