Optical Spectroscopy System Using Matched Filter for Signal Stability
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Solution Overview
Problem
Current optical spectroscopy systems face challenges in minimizing current leakage and nonlinear effects in switching circuits, reducing the duration of Walsh codes per unit time, distinguishing light sources, and minimizing white Gaussian noise without additional circuitry, while also being mobile and expandable.
Innovation Solution
The system employs a pipeline-structured matched filter, time-divided spread spectrum codes (TDSSC), and Walsh codes for code-modulating and demodulating light, using a reference clock for sampling, and integrates these features into a firmware-based system for a mobile and expandable optical spectroscopy system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional switching circuits are used in optical spectroscopy systems, then the system can operate with standard circuit design, but current leakage and nonlinear effects occur in the switching circuits
Solution Approach 1:
The patent replaces conventional electronic switching circuits with a pulse generator that directly modulates the light source intensity. This substitution eliminates the need for electronic switches in the optical path, thereby removing current leakage and nonlinear effects associated with traditional switching circuits while maintaining the ability to control light delivery to the subject.
2Use of energy by moving object
If the duration of Walsh codes per unit time is increased, then more light energy can be transmitted, but the duration of Walsh codes per unit time becomes too long
Solution Approach 1:
The patent employs periodic pulse generation with variable duty cycles to modulate the light source. By using periodic pulsing instead of continuous Walsh code transmission, the system can concentrate light energy into shorter, more intense pulses while maintaining the same average power delivery. This periodic action allows efficient energy transmission without requiring excessively long Walsh code durations.
3Adaptability or versatility
If multiple light sources are used in the optical spectroscopy system, then more measurement channels can be obtained, but it becomes difficult to distinguish which light source emitted which light
Solution Approach 1:
The patent applies preliminary modulation to each light source using unique pulse patterns or duty cycles before the light interacts with the subject. By encoding identification information into the temporal characteristics of each light source's output in advance, the detection system can easily distinguish which light source emitted which light based on the timing and pattern of received signals, eliminating the need for complex source identification after emission.
4Reliability
If additional circuitry is added to minimize white Gaussian noise, then noise reduction can be achieved, but the system complexity increases
Solution Approach 1:
The patent replaces complex electronic noise filtering circuits with temporal encoding and decoding methods. By using unique pulse patterns for each light source and corresponding detection timing, the system can distinguish desired signals from noise without requiring additional analog filtering circuitry. This substitution achieves noise reduction through signal processing in the time domain rather than through additional hardware 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 minimizes current leakage and nonlinear effects, increases light intensity with the same total energy, distinguishes light sources, and reduces white Gaussian noise, enabling efficient data processing and visualization in a monitoring device with firmware updates and big data analysis.
Implementation Method 1
Near-infrared spectroscopy (NIRS) can measure the concentration changes of oxyhemoglobin and deoxyhemoglobin caused by the activation of neuronal cells
Implementation Method 2
Hemoglobin is also a kind of the chromophores, and exhibits a larger degree of absorption than water in a near-infrared region
Implementation Method 3
a matched filter for extracting one piece of data for each bit period by accumulating input signals in a continuous time domain using a reference clock used for the light emission as a sampling clock
Implementation Method 4
a pipeline-structured matched filter to implement a matched filter structure for the same time as a bit period of input Walsh codes, and minimize current leakage and nonlinear effects occurring in a switching circuit
Implementation Method 5
use time-divided spread spectrum codes (TDSSC) to reduce duration of 1 of Walsh codes per unit time and inject more intense light, thereby increasing the intensity of the light with the same total energy
Implementation Method 6
accumulate input signals using a reference clock used for light emission as a sampling clock, thereby minimizing white Gaussian noise without additional circuitry such as an additional phase locked loop (PLL)
Data Source
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AI summary
Disclosed are an optical spectroscopy system using a matched filter-based broadband signal receiver for stable data extraction, and a method for controlling the optical spectroscopy system. The optical spectroscopy system may comprise: a light transmission unit for irradiating light on a particular region of a subject by means of a plurality of light sources, wherein the light irradiated from the plurality of light sources is code-modulated by means of the Walsh codes and then irradiated; and a light receiving unit for detecting emergent light which has passed through the particular region, wherein the light source is identified by demodulating the light by means of the Walsh codes.