Single-Stage RF Amplifier With Phase-Shift Feedback Compensation
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Solution Overview
Problem
Magnetic resonance tomography scanners face challenges in amplifying weak signals from antenna coils with low noise and high linearity, often resulting in increased power consumption and unwanted heating due to the need for multiple amplifier stages.
Innovation Solution
A single-stage radio frequency amplifier with a phase shifter is used, which includes an active component and passive elements to provide stable amplification without additional power loss, reducing feedback and heat generation by decoupling the output from the input with a predetermined phase shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple amplifier stages are used to achieve high amplification, then the amplification requirement is met, but power consumption increases and heat generation occurs
Solution Approach 1:
The patent combines the amplification function and feedback compensation function into a single amplifier stage. The first amplifier stage performs both signal amplification and feedback compensation simultaneously, eliminating the need for separate amplifier stages. This merging of functions achieves high overall amplification while reducing power consumption compared to using multiple discrete amplifier stages.
2Power
If multiple amplifier stages are used to achieve high amplification, then the amplification requirement is met, but heat generation increases causing unwanted heating
Solution Approach 1:
The patent merges the feedback compensation function into the first amplifier stage, eliminating the need for additional amplifier stages that would generate heat. By achieving both high amplification and feedback compensation in a single stage, the overall heat generation is reduced compared to cascaded multi-stage amplifier configurations.
3Use of energy by moving object
If high amplification is achieved in a single stage, then power consumption is reduced, but feedback tendency increases due to parasitic capacitances
Solution Approach 1:
The patent introduces a feedback path that taps a portion of the output signal from the first amplifier stage and feeds it back to the input. This feedback mechanism compensates for the feedback tendency caused by parasitic capacitances. The feedback signal is combined with the input signal to stabilize the amplifier operation, allowing high amplification to be achieved while maintaining stability and reducing unwanted feedback effects.
4Measurement precision
If class-A amplifier operation is used to achieve large dynamic range and high linearity, then signal quality is improved, but closed current requirement increases
Solution Approach 1:
The patent combines feedback compensation within the single class-A amplifier stage, allowing the amplifier to operate in the linear range with high signal quality while the feedback mechanism optimizes the current requirements. The feedback path helps maintain linearity and dynamic range without requiring excessively high closed current by compensating for parasitic effects that would otherwise require higher current margins.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables stable and high preamplification of antenna signals directly on the source with reduced power loss and heat generation, maintaining signal quality while minimizing unwanted heating on the patient.
Implementation Method 1
The phase shifter is in signal connection with the signal output and the signal input of the signal amplifier and is configured to couple a predetermined portion of an output signal of the signal amplifier with a predetermined phase shift into the signal input of the signal amplifier
Data Source
AI summary
A single-stage radio frequency amplifier is provided with a signal amplification stage for a magnetic resonance tomography scanner, for example as a low-noise preamplifier in a local coil. The radio frequency amplifier includes a signal input, a signal amplifier, a signal output of the signal amplifier and a phase shifter. The phase shifter is in signal connection with the signal output and the signal input of the signal amplifier and is configured to couple a predetermined portion of an output signal of the signal amplifier with a predetermined phase shift into the signal input of the signal amplifier.