Galvanic Isolation and Impedance Matching in Endoscopy Cables
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Solution Overview
Problem
Existing endoscopy arrangements face challenges in maintaining high transmission quality of image and video signals while ensuring medical safety standards, particularly in preventing harmful discharge currents and signal distortions during transmission.
Innovation Solution
The implementation of galvanic isolation between the endoscope and camera controller, combined with an impedance matching circuit arranged upstream of the signal processing circuitry, which compensates for signal changes and avoids reflections, ensuring high-quality imaging and electrical safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If galvanic isolation is implemented between endoscope and camera controller, then electrical safety is improved, but signal transmission quality deteriorates due to impedance mismatch and signal distortion
Solution Approach 1:
An impedance matching circuit is introduced as an intermediary component between the galvanic isolation and the signal processing circuitry. This intermediary circuit compensates for signal distortions and maintains signal quality while allowing the galvanic isolation to provide electrical safety. The impedance matching circuit acts as a mediator that resolves the conflict between safety isolation and signal integrity.
Solution Approach 2:
The system is segmented into distinct functional sections: the endoscope, the cable, the galvanic isolation, and the impedance matching circuit. By separating the galvanic isolation from the signal processing circuitry and placing the impedance matching circuit between them, the design allows each component to perform its specific function optimally without interfering with the other's performance characteristics.
2Reliability
If galvanic isolation is placed close to the endoscope, then electrical safety is improved, but signal transmission distance and quality are compromised
Solution Approach 1:
The impedance matching circuit serves as a mediator that extends the effective signal transmission distance by compensating for signal losses and distortions that occur after galvanic isolation. This allows the galvanic isolation to be positioned close to the endoscope for safety while maintaining signal quality over the required transmission distance through the cable.
3Manufacturing precision
If impedance matching circuit is added to maintain signal quality, then signal transmission quality is improved, but device complexity increases
Solution Approach 1:
The impedance matching circuit compensates for signal distortions by adjusting electrical parameters such as impedance values and frequency characteristics. By changing these parameters dynamically or through fixed design values, the circuit maintains signal quality without requiring complex active control systems, thus balancing performance with simplicity.
4Ease of operation
If cable length is increased to improve ergonomics, then ease of operation is improved, but signal quality deteriorates due to transmission losses and reflections
Solution Approach 1:
The impedance matching circuit acts as a mediator that compensates for signal losses and reflections that increase with cable length. This allows the cable to be made longer for improved ergonomics and ease of operation while the impedance matching circuit maintains signal quality by correcting the distortions introduced by the extended transmission path.
Solution Approach 2:
The impedance matching circuit applies preliminary compensation for signal distortions before they become problematic. By pre-adjusting for the expected signal losses and reflections in longer cables, the system maintains signal quality even when cable length is increased for ergonomic purposes.
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 maintains signal quality and ensures electrical safety by preventing harmful discharge currents and signal distortions, allowing for compact and efficient endoscopy arrangements that meet medical standards.
Implementation Method 1
a galvanic isolation is formed between the endoscope and a signal processing circuitry arrangement of the camera controller
Implementation Method 2
an impedance matching circuit is formed, said impedance matching circuit being arranged upstream of the signal processing circuitry arrangement of the camera controller in the signal direction
Data Source
AI summary
To improve the quality of transmission of a signal from an image sensor to a camera controller of an endoscopy arrangement by a cable while maintaining electrical safety standards, a first circuitry arrangement used to transmit the signal within the cable includes galvanic isolation from a second circuitry arrangement used to further process the signal within the camera controller. The galvanic isolation is formed downstream of a proximal end of the cable in the signal direction, and the first circuitry arrangement has a, preferably passive, impedance matching circuit, for example arranged at the proximal end of the cable or in the camera controller. This impedance matching circuit is configured to compensate signal distortions, which arise during the transmission of the signal that is produced by the image sensor to the camera controller, preferably such that a frequency spectrum of the signal produced by the image sensor can be reproduced.