Variable Sampling Correlator for Diffuse Correlation Spectroscopy
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Solution Overview
Problem
Current Diffuse Correlation Spectroscopy techniques require excessive resources and memory to calculate the intensity autocorrelation function g2(τ), especially when dealing with longer time lag regions, due to the need for multiple sampling gates and extensive data storage, leading to increased time and memory requirements.
Innovation Solution
A correlator system that adjusts the sampling time period and data length based on the decay time calculated from the correlation function, using a parameter determining circuit to optimize the sampling process and reduce memory usage, while validating the correlation function through coherence and plateau level analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple fixed sampling gates are used to calculate g2(τ) for longer time lag regions, then the measurement precision is improved, but the device complexity and memory requirements increase
Solution Approach 1:
The patent applies dynamics by making the sampling gate time period variable rather than fixed. The control circuit dynamically adjusts the sampling gate time period based on the decay time of the correlation function, allowing a single sampling gate to adaptively cover different time lag regions. This eliminates the need for multiple fixed sampling gates while maintaining measurement precision across the full time range.
Solution Approach 2:
The patent changes the parameter of sampling gate time period from a fixed value to a variable that is adjusted based on the decay time parameter of the correlation function. By changing this key parameter dynamically, the system can accurately measure g2(τ) across different time lag regions without requiring multiple separate sampling gates, thus reducing device complexity.
2Measurement precision
If multiple sampling gates with associated memories are used to calculate g2(τ), then the measurement precision is improved, but the memory requirements and loss of time increase
Solution Approach 1:
The patent extracts the need for multiple separate memories associated with each sampling gate by using a single variable sampling gate. The control circuit manages the photon count data from a single sampling gate through multiple passes with different time periods, eliminating the requirement for multiple parallel memory structures while maintaining the capability to calculate g2(τ) across all time lag regions.
Solution Approach 2:
The single sampling gate in the patent serves multiple functions by being reused across different time lag regions through dynamic adjustment of its time period. Instead of requiring separate dedicated sampling gates and memories for each time region, one sampling gate universally handles all measurement requirements by adapting its parameters, thus reducing overall memory requirements.
3Device complexity
If fixed sampling gates are used for calculating g2(τ), then the device complexity is simplified, but the productivity and output rate decrease
Solution Approach 1:
The patent introduces dynamics into the correlator by implementing a control circuit that dynamically adjusts the sampling gate time period based on real-time analysis of the correlation function's decay time. This dynamic adaptation allows the system to optimize measurement speed and output rate while maintaining a relatively simple overall structure, avoiding the complexity of multiple fixed gates while achieving high productivity.
Solution Approach 2:
The patent implements feedback by using the calculated decay time from the correlation function to control and adjust the sampling gate time period. This feedback loop enables the system to automatically optimize its operation for different measurement conditions, improving productivity and output rate without requiring complex predetermined configurations or multiple fixed sampling gates.
Data Source
AI summary
The present disclosure relates in general to Diffuse Correlation Spectroscopy system for obtaining an autocorrelation function, and more particular, to a correlator and method for controlling a sampling time period and data length used for calculating an autocorrelation function. The correlator may include, a sampling gate circuit which is open during a variable time period and provides a data sample, a correlation circuit which calculates a correlation function from the data sample provided from the sampling gate circuit, and a parameter determining circuit which determines a sampling time period to be used by the sampling gate circuit based on the correlation function.