Variable Delay Circuit for OCT Signal Timing
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Solution Overview
Problem
Optical coherence tomographic devices using K-clock signals face challenges in suppressing interference signal distortion when sampled at different wavelength regions due to varying delay times through electrical circuits, leading to mismatched input timings for the sample clock and interference signals.
Innovation Solution
Incorporating a delay circuit that adjusts delay amounts based on wavelength regions, ensuring synchronized input timings for the sample clock and interference signals by switching between different delay settings for each wavelength region, allowing for precise matching of signal processor inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a delay circuit is used to synchronize the input timing of the sample clock signal and the interference signal, then the temporal matching between signals is improved, but the device complexity increases
Solution Approach 1:
The delay amount of the delay circuit is made variable rather than fixed, allowing it to be dynamically adjusted based on the wavelength region. This enables the system to compensate for frequency-dependent delay variations without requiring multiple fixed delay circuits, thus resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The delay circuit's delay amount is changed as a parameter based on the wavelength region in which the interference signal is sampled. By adjusting the delay amount parameter, the system achieves accurate temporal matching for different wavelength regions while using a single delay circuit, avoiding the need for complex multi-circuit configurations.
2Adaptability or versatility
If the interference signal is sampled in different wavelength regions, then the versatility of the system is improved, but the measurement precision deteriorates due to varying delay amounts
Solution Approach 1:
The delay circuit is designed with variable delay capability that can be dynamically adjusted according to the selected wavelength region. This dynamic adjustment ensures that the delay amount is optimized for each wavelength region, maintaining sampling accuracy across multiple wavelength regions without sacrificing versatility.
Solution Approach 2:
The system changes the delay parameter of the delay circuit based on the wavelength region being used. By linking the delay parameter to the wavelength region selection, the system achieves both versatility (support for multiple wavelength regions) and measurement precision (accurate sampling in each region).
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 configuration effectively suppresses interference signal distortion across different wavelength regions by ensuring the sample clock and interference signal are simultaneously inputted to the signal processor, improving the accuracy of tomographic information acquisition.
Implementation Method 1
a light receiving element configured to receive interference light and to convert the interference light to an interference signal
Data Source
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AI summary
An optical coherence tomographic device may include: a light source of wavelength sweeping type; a measurement optical system; a reference optical system; a light receiving element that receives interference light and to convert the interference light to an interference signal; a sample clock signal generator that generates a sample clock signal at regular frequency intervals; a signal processor that samples the interference signal based on the sample clock signal; a processor; and a delay circuit that delay at least one of the sample clock signal and the interference signal. The signal processor may sample the interference light in first and second wavelength regions within an entire wavelength region. The delay circuit may be configured such that a first delay amount when the interference signal is sampled in the first wavelength region is different from a second delay amount when the interference signal is sampled in the second wavelength region.