Optical Signal Detector Using Frequency Modulation to Reduce Crosstalk
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Solution Overview
Problem
Current diagnostic assays face challenges in distinguishing between different emission signals due to optical crosstalk, particularly when excitation and emission wavelengths overlap, leading to interference and inaccurate signal detection.
Innovation Solution
The method involves using synchronous detection techniques, including modulating excitation signals with specific frequencies and employing Goertzel signal processing to isolate and digitize emission signals at predetermined frequencies, thereby reducing crosstalk and enhancing signal specificity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple fluorophores with overlapping excitation and emission wavelengths are used to detect different target nucleic acids, then the assay can detect multiple targets in parallel, but optical crosstalk occurs leading to interference and inaccurate signal detection
Solution Approach 1:
The patent applies periodic action by modulating excitation signals at different frequencies for different fluorophores. Each fluorophore is excited by a modulated signal at its specific frequency (e.g., first fluorophore at frequency f1, second fluorophore at frequency f2), allowing the detection system to distinguish between overlapping emission signals through frequency discrimination. This periodic modulation enables parallel detection of multiple targets while maintaining signal accuracy by separating signals in the frequency domain.
Solution Approach 2:
The patent changes the frequency parameter of excitation signals to resolve optical crosstalk. By assigning different modulation frequencies to different fluorophores, the system transforms the detection problem from wavelength-based separation to frequency-based separation. This parameter change allows the use of fluorophores with overlapping spectra while maintaining measurement precision through frequency-selective detection.
2Measurement precision
If synchronous detection techniques with frequency modulation are used to reduce optical crosstalk, then signal detection accuracy improves, but the device complexity increases due to additional signal processing requirements
Solution Approach 1:
The patent replaces complex optical filtering mechanisms with electronic signal processing. Instead of using multiple physical filters to separate overlapping wavelengths, the system uses electronic frequency modulation and digital signal processing (Goertzel algorithm) to distinguish signals. This substitution reduces optical component complexity while achieving the same crosstalk reduction goal through electrical domain processing.
Solution Approach 2:
The patent introduces frequency modulation as an intermediary mechanism between the excitation source and the fluorophores. By modulating excitation signals at distinct frequencies before they reach the fluorophores, and then using frequency-selective detection, the system creates an intermediate frequency domain that simplifies signal separation. This intermediary approach avoids direct wavelength-based separation 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 effectively reduces optical crosstalk and noise, allowing for accurate detection of multiple optical signals from different analytes by isolating signals at their respective modulation frequencies, improving the precision of diagnostic assays.
Implementation Method 1
directing an excitation signal at the receptacle. The excitation signal has a predetermined excitation wavelength that excites an emission moiety, which emits an emission signal that is associated with the excitation wavelength and has a predetermined emission wavelength
Implementation Method 2
The method involves using synchronous detection techniques, including modulating excitation signals with specific frequencies and employing Goertzel signal processing to isolate and digitize emission signals at predetermined frequencies
Implementation Method 3
modulating excitation signals with specific frequencies and employing Goertzel signal processing to isolate and digitize emission signals at predetermined frequencies
Data Source
AI summary
Systems and method for detecting optical signals, and for discriminating optical signals emitted by an emission moiety that is excited by an associated excitation signal from background signals and other optical noise, employing digital techniques for determining the portion of a detected optical signal having a modulation frequency corresponding to a modulation of the associated excitation signal.