Feedback Signal Correction Circuit for MR Physiological Detection
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Solution Overview
Problem
Existing methods are inadequate for effectively suppressing disturbance signals with large amplitudes in magnetic resonance (MR) measurements, particularly those caused by gradient pulses, which overwhelm physiological signals like ECG and respiration, making it difficult to process vital parameter data accurately.
Innovation Solution
A circuit assembly comprising a voltage-controlled circuit with transistors, an operational amplifier, and a low-pass filter, where the output voltage from the operational amplifier is fed back to the low-resistance terminal of the voltage-controlled circuit element, allowing immediate suppression of disturbances by stopping signal forwarding to the operational amplifier during disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If filters are used to reduce MR interferences in physiological signals, then disturbance suppression is achieved, but the method is only effective for small disturbance amplitudes and fails when disturbance amplitudes are large (up to a factor of 1000 greater than useful signal)
Solution Approach 1:
The patent implements a feedback mechanism where the output signal is fed back to the control input of the voltage-controlled circuit element. This feedback loop enables the circuit to dynamically adjust its behavior based on the output signal characteristics, allowing effective suppression of large disturbance amplitudes by continuously monitoring and responding to signal conditions.
Solution Approach 2:
The patent employs a voltage-controlled circuit element (such as a transistor or FET) whose conductivity can be dynamically adjusted by applying control voltages. This dynamic control allows the circuit to adapt its impedance and signal transmission characteristics in real-time, enabling effective suppression of disturbances with amplitudes up to 1000 times greater than the useful signal.
2Object-affected harmful factors
If sample-and-hold circuits are used to suppress disturbances by interrupting signal processing, then disturbance recognition is achieved, but disturbance peaks persist in the period before elimination and distort the signal
Solution Approach 1:
The patent introduces a voltage-controlled circuit element as an intermediary component between the input signal and the operational amplifier. This intermediary can be dynamically controlled to block or pass signals, providing smooth transition without the abrupt interruptions characteristic of sample-and-hold circuits, thereby avoiding signal distortion before disturbance elimination.
3Object-affected harmful factors
If peak limitation methods are used to isolate and filter extreme signal values, then peak suppression is achieved, but the signal requires delayed combination with filter signal, reducing real-time processing capability
Solution Approach 1:
The patent applies preliminary action by pre-configuring the voltage-controlled circuit element to respond to disturbance conditions before they fully manifest in the output. The feedback mechanism enables the circuit to anticipate and counteract disturbances in advance, eliminating the need for delayed signal combination and maintaining real-time processing capability.
Data Source
AI summary
A circuit assembly for correction of an input signal including a useful signal and a disturbance signal comprises: a voltage-controlled circuit having at least one voltage-controlled circuit element, an input interface and an output interface, a resistor connected upstream of the voltage-controlled circuit in series with the voltage-controlled circuit, an operational amplifier having a first amplifier input, a second amplifier input and an amplifier output, and a low-pass filter connected between the input interface of the at least one voltage-controlled circuit element and the first amplifier input of the operational amplifier, wherein the output voltage from the operational amplifier is fed back to the low-resistance terminal of the circuit element in that the low-resistance terminal of the at least one voltage-controlled circuit element is electrically connected to the amplifier output of the operational amplifier and to the second amplifier input of the operational amplifier.