Endoscope Clock Transmission via Optical Fiber and Digital Phase Sync
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Solution Overview
Problem
Endoscope systems face challenges in maintaining high accuracy and stability of timing signals at the distal end portion due to signal degradation and noise interference, particularly with the use of coaxial cables and external phase synchronization circuits, which are prone to noise and size limitations in medical environments.
Innovation Solution
An endoscope system design where the phase synchronization circuit with a feedback mechanism is contained within an external apparatus, and the base clock is optically transmitted to the distal end portion, eliminating the need for external attachments and reducing noise interference, while allowing for high-frequency timing signals to be generated accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the oscillator clock frequency is raised to meet higher imaging element definition requirements, then the timing signal frequency is improved, but the signal quality deteriorates and noise radiation increases when transmitted through fine-wire coaxial cable
Solution Approach 1:
The patent introduces a twisted pair cable as an intermediary transmission medium to replace the fine-wire coaxial cable. This intermediary enables high-frequency clock signals to be transmitted with better signal quality and reduced noise radiation by utilizing differential signaling, which is inherently more resistant to electromagnetic interference and signal degradation at high frequencies.
2Measurement precision
If an external attachment type phase synchronization circuit is used in the distal end portion to achieve high accuracy, then the base clock accuracy is improved, but the circuit size increases and noise susceptibility increases
Solution Approach 1:
The patent extracts the phase synchronization circuit from the distal end portion and relocates it to the external apparatus. This extraction eliminates the need for bulky external attachment type circuits in the constrained distal end space, while still achieving high base clock accuracy through the use of an all-digital phase synchronization circuit in the external apparatus that processes the transmitted clock signal.
Solution Approach 2:
The patent replaces the traditional external attachment type phase synchronization circuit with an all-digital phase synchronization circuit implemented in the external apparatus. This substitution uses digital signal processing techniques to achieve high accuracy without requiring the complex analog components and large physical space of external attachment circuits.
3Object-generated harmful factors
If a twisted pair cable is used to transmit high-speed oscillator clock, then noise radiation is reduced, but the clock accuracy may be insufficient for extremely high-frequency timing signals
Solution Approach 1:
The patent introduces an all-digital phase synchronization circuit in the external apparatus as an intermediary processing stage. This circuit receives the clock signal transmitted through the twisted pair cable and performs digital phase synchronization to achieve the required high accuracy, compensating for any accuracy limitations of the twisted pair transmission while maintaining low noise radiation.
4Reliability
If the phase synchronization circuit feedback wiring is exposed to noise in the medical environment, then the system becomes more susceptible to interference, but shielding increases size and complexity
Solution Approach 1:
The patent replaces the analog feedback wiring system with an all-digital phase synchronization circuit that operates in the digital domain. This substitution eliminates the need for complex electromagnetic shielding of analog feedback paths, as digital signals are inherently more resistant to noise. The all-digital implementation maintains synchronization stability without requiring additional shielding structures that would increase size and complexity.
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 approach enables stable and accurate transmission of high-frequency timing signals to the distal end portion, minimizing noise and signal degradation, thus ensuring high-quality video transmission and system stability, even in noisy medical environments.
Implementation Method 1
a base clock creation section that creates the base clock using a phase synchronization circuit that has a feedback mechanism
Implementation Method 2
a base clock transmitting section that converts the base clock into an optical signal and transmits the optical signal to the base clock receiving section
Implementation Method 3
a base clock receiving section that receives as an optical signal a base clock which is the basis of the timing signal and then converts the received optical signal into an electrical signal
Data Source
AI summary
This endoscope system includes: a distal end portion which is inserted inside a specimen and which has an imaging section that creates video signals, a video signal processing section that processes the video signals, a video transmitting section that transmits the processed video signals, a timing signal creation section that creates a timing signal needed to drive the imaging section, the video signal processing section, or the video transmitting section, and a base clock receiving section that receives as an optical signal a base clock which is the basis of the timing signal and then converts the received optical signal into an electrical signal; and an external apparatus having an insertion portion which guides the distal end portion into the specimen, a monitor that displays the video signals, and a video processor that processes the video signals from the distal end portion and outputs them to the monitor.