Impedance Matching Network for Endoscopic Rotational Imaging Noise Reduction
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Solution Overview
Problem
Endoscopic rotational imaging devices face excessive signal noise due to electromagnetic interference, particularly in the 20-60 megahertz spectrum, which hinders the generation of clear images, especially in narrow body lumens where conventional endoscopes cannot accommodate, leading to inefficient imaging capabilities.
Innovation Solution
The implementation of an impedance matching network between a proximal and distal imaging core, comprising an inductor and capacitor in parallel, with a characteristic impedance of 55-75 ohms, to match impedance and reduce noise, along with shielded twisted pairs for signal transmission, facilitates effective signal conduction and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional endoscopes are used for imaging, then the device structure is simple, but the device cannot accommodate narrow body lumens and generates excessive signal noise
Solution Approach 1:
An impedance matching network is introduced as an intermediary component between the distal imaging core and proximal imaging core. This network includes a transformer with specific turns ratios and impedance matching circuits that actively reduce electromagnetic interference and signal noise in the 20-60 MHz spectrum, resolving the noise issue while maintaining a manageable device structure through modular design
Solution Approach 2:
The patent employs a nested structure where the distal imaging core with rotational transducer is positioned within a telescoping catheter section, which is itself nested within the proximal imaging core assembly. This nested doll approach enables access to narrow body lumens while organizing complex components in a compact, hierarchical manner that manages overall device complexity
2Ease of operation
If the distal imaging core uses smaller diameter conductors to fit narrow lumens, then the device can access narrow body lumens, but signal noise increases due to impedance mismatch
Solution Approach 1:
The impedance matching network dynamically adjusts electrical parameters including impedance values and signal frequency characteristics. The transformer uses specific turns ratios (e.g., 4:1 or 6:1) and the matching circuits adjust capacitance and inductance values to optimize signal transmission through the smaller diameter distal imaging core conductors, eliminating noise while preserving access capability
Solution Approach 2:
The impedance matching network serves as an intermediary between the small-diameter distal imaging core and the larger proximal imaging core. This intermediary actively transforms and conditiones the signal, allowing the small conductors to function effectively without generating excessive noise by bridging the impedance gap between different conductor sizes
3Volume of moving object
If shielded twisted pairs with smaller diameters are used in the distal imaging core, then the device fits narrow lumens, but impedance matching becomes difficult causing signal degradation
Solution Approach 1:
The patent specifies precise parameter ranges for the shielded twisted pairs including conductor diameter (46-52 AWG), shield braid coverage (80-90%), and characteristic impedance (55-75 ohms). The impedance matching network is designed with corresponding parameters (transformer turns ratios, capacitor values of 40-60 pF, inductor values of 170-210 nH) that work together to maintain reliable signal transmission despite the small cable diameter
Solution Approach 2:
Different sections of the imaging system use locally optimized conductor specifications. The distal imaging core uses smaller diameter shielded twisted pairs (46-52 AWG) appropriate for narrow lumens, while the proximal imaging core uses larger conductors (42-50 AWG). The impedance matching network at the junction point provides local quality transformation to ensure reliable signal transmission across the transition between these different local specifications
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 significantly enhances image clarity by minimizing signal noise, enabling accurate radial imaging in narrow body lumens, thereby improving the usability and applicability of endoscopic rotational imaging devices.
Implementation Method 1
an impedance matching network may be disposed between a proximal imaging core and a distal imaging core
Implementation Method 2
a rotational transformer having first and second ends, the first end may be coupled to the connector
Implementation Method 3
a first shielded twisted pair (STP) of a first diameter and the distal imaging core may comprise a distal drive cable and a second STP of a second diameter
Data Source
AI summary
The present disclosure includes devices, systems, and methods for reducing signal noise in endoscopic rotational imaging. Many embodiments include an elongate member that includes an impedance matching network disposed between a proximal imaging core and a distal imaging core. In many such embodiments, the elongate member may connect a controller at the proximal end and include a rotational transducer at the distal end. In various embodiments, the proximal and distal imaging cores may include a plurality of insulated conductors disposed within a shield (e.g., a shielded twisted pair (STP)). In various such embodiments, the insulated conductors may be utilized to communicate differential signals between the controller and the rotational imaging transducer. In some embodiments, the insulated conductors in the proximal imaging core may have a larger diameter than the insulated conductors in the distal imaging core.