NMR Signal Processing via Modulus Calculation
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Solution Overview
Problem
Current NMR techniques require manual and time-consuming corrections for phase and frequency shifts in FID signals, especially when using multiple antennas, which complicates the recombination of signals and reduces the signal-to-noise ratio (SNR).
Innovation Solution
The method involves calculating the modulus of the FID signal, which automatically corrects for phase and frequency shifts due to sample movement and antenna inhomogeneities, allowing for the substitution of noise-reduced portions of the spectrum to improve SNR without additional processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual phase and frequency corrections are applied to FID signals, then measurement precision is improved, but loss of time increases and device complexity increases
Solution Approach 1:
The patent applies preliminary action by performing phase and frequency corrections automatically during the signal acquisition phase using reference signals, rather than requiring manual corrections after acquisition. The system pre-establishes correction parameters through reference signal analysis and applies them automatically to subsequent FID signals, eliminating time-consuming manual intervention while maintaining high precision.
Solution Approach 2:
The patent introduces an intermediary reference signal that mediates between the B0 field variations and the FID signals. This reference signal captures the phase and frequency shifts caused by field inhomogeneities and sample movement, allowing automatic correction to be applied to the analytical signals without manual intervention, thus resolving the contradiction between precision and time loss.
2Reliability
If multiple antennas are used for signal acquisition, then signal-to-noise ratio is improved, but device complexity increases and signal recombination becomes more difficult
Solution Approach 1:
The patent applies universality by using a single reference signal acquisition process that serves multiple antennas simultaneously. The reference signal is acquired with the same phase and frequency corrections applied to all antenna signals, creating a universal correction framework that simplifies the recombination process while maintaining improved signal-to-noise ratio through multi-antenna acquisition.
Solution Approach 2:
The patent applies homogeneity by ensuring that all antenna signals undergo identical phase and frequency correction processes using the same reference signal parameters. This homogeneous treatment of multi-antenna signals simplifies their recombination by eliminating the need for individualized correction procedures, thereby reducing device complexity while preserving the signal-to-noise ratio benefits.
3Reliability
If sample movement and B0 field inhomogeneities are present, then measurement reliability deteriorates, but manual correction increases processing time
Solution Approach 1:
The patent applies feedback by continuously monitoring phase and frequency shifts through reference signal acquisition and using this information to automatically adjust correction parameters for FID signals. This closed-loop feedback mechanism maintains high measurement reliability despite sample movement and field inhomogeneities while eliminating the need for time-consuming manual corrections, as the system self-corrects in real-time.
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 simplifies the correction process, enhances the signal-to-noise ratio, and reduces processing time and costs by eliminating the need for manual phase and frequency corrections, enabling more precise identification and quantification of species in NMR analysis.
Implementation Method 1
When placed in a strong external static magnetic field, the nuclei's spin aligns either with or against the external magnetic field, while simultaneously undergoing precession at the Larmor frequency
Implementation Method 2
the nuclei's spin aligns either with or against the external magnetic field, while simultaneously undergoing precession at the Larmor frequency, which depends on the intensity of the external field, B0
Implementation Method 3
Nuclear nuclei can then be disturbed by a radio wave or radio frequency (RF), all the more easily when its frequency is close to the Larmor frequency and therefore preferably resonates with it
Implementation Method 4
The disturbance has the effect of changing the spin orientation, possibly even flipping it in the opposite direction permitted by the external magnetic field B0
Implementation Method 5
It is this flip and the return to equilibrium or relaxation that generates the electrical signal detected in all NMR instruments. This signal is usually referred to as FID, from the English 'free induction decay'
Data Source
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AI summary
The invention especially relates to a method for analysing, by nuclear magnetic resonance (NMR), at least one sample containing at least one species to be characterised and a reference species, the method comprising the following steps:- acquiring (1330), via one or more antennae, one or more complex free induction decay (FID) signals (S(t)); obtaining (1323) an FID spectrum S(ω) by applying a Fourier transform to the signal S(t), the FID spectrum S(ω) obtained containing two portions (UFR, DFR) each extending from the resonant frequency (F0Ref) of the reference species and on either side of F0Ref, respectively, the frequency of the species to be characterised being located in a spectrum portion selected from said two portions (UFR, DFR); - modelling (1321) the signal Sref(t) of the reference species on the basis of the real and complex parts of the at least one complex FID signal S(t); - obtaining (1322) a spectrum Sref(ω) of the reference species containing only the reference species, by applying a Fourier transform to the model of the signal Sref(t) of the reference species; - obtaining (1324) a modified FID spectrum, Formula (I), by substituting the portion of the FID spectrum S(ω) that does not contain the species to be characterised with the corresponding portion of the spectrum Sref(ω); - applying (1325) an inverse Fourier transform to formula (I) in order to obtain a modified signal Formula (II); and - calculating (1326) the modulus of the modified FID signal Formula (II).