US3968424A
Expired / Lapsed
US
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Fourier transform NMR spectroscopy employing a phase modulated rf carrier
Assignee: Varian Medical Systems Inc
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Filing: 1974-08-01
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Granted: 1976-07-06
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Expires: 1994-08-01
Abstract
Abstract A nuclear magnetic resonance Fourier transform spectrometer includes a pulse modulated rf transmitter for delivering a train of radio frequency pulses having a pulse width pulse repetition rate to generate Fourier side bands to cover the spectral lines of the sample to be analyzed for exciting resonance of different resonance lines, if any, within the sample. Resonance of the sample is scanned in between successive transmitted pulses to obtain a multiplicity of successive time displaced components which are sampled and stored in a multiplicity of memory channels of a computer for time averaging thereof. The time averaged signal components are periodically read out and Fourier transformed to obtain a time averaged spectrum of the sample under analysis. Anomalous phase and intensity effects in the detected spectral lines are avoided by periodically shifting the phase of the pulse modulated carrier signal from one phase to another of at least three different relative phases in accordance with a predetermined sequence.
Inventors
- 👤 Richard R. Ernst
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:20
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/46; G01R33/28; G01R33/32; G01R33/36; G01R33/3607
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
172 words
In a magnetic resonance spectrometer: means for generating a band of radio frequency energy for irradiation of a sample of matter to be analyzed, such band of energy having a sufficient bandwidth to cover the spectral lines of the sample to be analyzed for simultaneously exciting radio frequency magnetic resonance of different resonance spectral lines, if any, within the sample; means for detecting the excited resonance of the sample to obtain a composite resonance signal therefrom for analysis of the sample; means for repetitively time scanning, sampling and storing a multiplicity of successive time displaced components of the composite resonance signal in a multiplicity of respective channels; means for reading out the signal components stored in such channels; and said means for generating the band of radio frequency energy for irradiation of the sample including, means for generating a radio frequency carrier signal, and means for periodically shifting the phase of said carrier signal from one phase to another of at least three different relative phases in accordance with a predetermined sequence.
Claim 2
Dependent Claim
172 words
In a magnetic resonance spectrometer: means for generating a band of radio frequency energy for irradiation of a sample of matter to be analyzed, such band of energy having a sufficient bandwidth to cover the spectral lines of the sample to be analyzed for simultaneously exciting radio frequency magnetic resonance of different resonance spectral lines, if any, within the sample; means for detecting the excited resonance of the sample to obtain a composite resonance signal therefrom for analysis of the sample; means for repetitively time scanning, sampling and storing a multiplicity of successive time displaced components of the composite resonance signal in a multiplicity of respective channels; means for reading out the signal components stored in such channels; and said means for generating the band of radio frequency energy for irradiation of the sample including, means for generating a radio frequency carrier signal, and means for periodically shifting the phase of said carrier signal from one phase to another of at least three different relative phases in accordance with a predetermined sequence.
Claim 3
Dependent Claim
62 words
The apparatus of claim 1 wherein said phase shifting means for shifting the phase of the carrier energy includes, a plurality of delay means one for each of said phase relations relative to a reference phase relation, and means for sequentially switching respective ones of said delay means in circuit between said carrier signal generating means and the sample to be irradiated.
Claim 4
Dependent Claim
114 words
The apparatus of claim 1 wherein said phase shifting means for shifting the phase of the carrier energy includes, a source of radio frequency energy at a number n times the frequency of said carrier signal energy to be generated, means for dividing the radio frequency energy output of said source by the number n to derive said radio frequency carrier signal, and delay means interposed in circuit between said source of radio frequency energy and said divider means for variably delaying the radio frequency energy to said divider means by a variable number of periods of the radio frequency energy to be divided to derive variable phase shifts of the generated carrier signal.
Claim 5
Dependent Claim
41 words
The apparatus of claim 1 including pulse modulator means for pulsing the intensity of the carrier signal energy to produce a train of radio frequency pulses for generating bands of Fourier components of radio frequency energy for irradiation of the sample.
Claim 6
Dependent Claim
112 words
The apparatus of claim 4 wherein said means for repetitively time scanning, sampling and storing a multiplicity of successive time displaced components of the composite resonance signal in a multiplicity of respective channels includes means for scanning the detected composite resonance signal during the period between successive pulses of the carrier signal energy, and storing and adding respective time displaced composite resonance signal components to those of previous scans to obtain time averaged data in separate respective channels of a memory, and means for Fourier transforming the read out time averaged signal components from the time domain into the frequency domain to obtain time average spectral data concerning the sample under analysis.
Claim 7
Dependent Claim
163 words
A nuclear magnetic resonance spectrometer for producing nuclear magnetic resonance spectrum from a sample under analysis comprising means for producing a unidirectional polarizing magnetic field enveloping said sample, means for applying a plurality of time-spaced pulses of driving radio frequency magnetic field to said sample for an experiment time T to produce a series of successive free precession signals from said sample responsive to said driving pulses, means for demodulating said free precession signals to obtain a series of free induction decay envelope signals, means for time-averaging discrete segments of said decay signals over the series of successive signals, wherein said means for applying a plurality of time-spaced pulses of driving radio frequency magnetic field includes means for providing said pulses in N i different phases relative to a reference phase where i is an integer greater than 2, means for dividing said experiment time T into i approximately equal time increments and means for arranging said time-spaced pulses in i different sets.
Claim 8
Dependent Claim
163 words
A nuclear magnetic resonance spectrometer for producing nuclear magnetic resonance spectrum from a sample under analysis comprising means for producing a unidirectional polarizing magnetic field enveloping said sample, means for applying a plurality of time-spaced pulses of driving radio frequency magnetic field to said sample for an experiment time T to produce a series of successive free precession signals from said sample responsive to said driving pulses, means for demodulating said free precession signals to obtain a series of free induction decay envelope signals, means for time-averaging discrete segments of said decay signals over the series of successive signals, wherein said means for applying a plurality of time-spaced pulses of driving radio frequency magnetic field includes means for providing said pulses in N i different phases relative to a reference phase where i is an integer greater than 2, means for dividing said experiment time T into i approximately equal time increments and means for arranging said time-spaced pulses in i different sets.
Claim 9
Dependent Claim
61 words
The spectrometer of claim 6 wherein said means for applying a plurality of time-spaced pulses includes means for selecting the sequence of said time-spaced pulses such that said first set is applied during said first time period, said second set is applied in said second time period and so on until said i set is applied in said i time period.
Claim 10
Dependent Claim
74 words
The spectrometer of claim 6 wherein said means for arranging said time-spaced pulses in i different sets includes means for generating the sets such that SET 1 equals N.sub.1, N.sub.2, N.sub.3 ... N.sub.i, N.sub.1, N.sub.2,
N.sub.3 ... N.sub.i ...
SET 2 equals N.sub.1, N.sub.3, N.sub.5, N.sub.7 ...
SET 3 equals N.sub.1, N.sub.4, N.sub.7, N.sub.10 ...
SET 4 equals N.sub.1, N.sub.5, N.sub.9, N.sub.13 ...
.
.
.
SET i equals N.sub.1, N.sub.1, N.sub.1, N.sub.1 ...
Claim 11
Dependent Claim
59 words
The spectrometer of claim 8 wherein i equals 4, such that SET 1 equals N.sub.1, N.sub.2, N.sub.3, N.sub.4, N.sub.1, N.sub.2,
N.sub.3, N.sub.4 ...
SET 2 equals N.sub.1, N.sub.3, N.sub.1, N.sub.3, N.sub.1, N.sub.3,
N.sub.1, N.sub.3 ...
SET 3 equals N.sub.1, N.sub.4, N.sub.3, N.sub.2, N.sub.1, N.sub.4,
N.sub.3, N.sub.2 ...
SET 4 equals N.sub.1, N.sub.1, N.sub.1, N.sub.1, N.sub.1, N.sub.1,
N.sub.1, N.sub.1 ...
Claim 12
Dependent Claim
177 words
In a method for obtaining magnetic resonance of a sample under analysis including the steps of: generating a band of radio frequency energy; irradiating a sample of matter to be analyzed with the band of radio frequency energy, such energy having a sufficient bandwidth to cover the spectral lines of the sample to be analyzed for simultaneously exciting radio frequency magnetic resonance of different resonance spectral lines, if any, within the sample; detecting the excited resonance of the sample to obtain a composite resonance signal therefrom for analysis of the sample; repetitively time scanning, sampling and storing a multiplicity of successive time displaced components of the composite resonance signal in a multiplicity of respective channels; reading out the signal components stored in such channels; and wherein the step of generating the band of radio frequency energy for irradiation of the sample includes the step of, generating a radio frequency carrier signal, and shifting the phase of the carrier signal from one phase to another of at least three different relative phases in accordance with a predetermined sequence.
Claim 13
Dependent Claim
177 words
In a method for obtaining magnetic resonance of a sample under analysis including the steps of: generating a band of radio frequency energy; irradiating a sample of matter to be analyzed with the band of radio frequency energy, such energy having a sufficient bandwidth to cover the spectral lines of the sample to be analyzed for simultaneously exciting radio frequency magnetic resonance of different resonance spectral lines, if any, within the sample; detecting the excited resonance of the sample to obtain a composite resonance signal therefrom for analysis of the sample; repetitively time scanning, sampling and storing a multiplicity of successive time displaced components of the composite resonance signal in a multiplicity of respective channels; reading out the signal components stored in such channels; and wherein the step of generating the band of radio frequency energy for irradiation of the sample includes the step of, generating a radio frequency carrier signal, and shifting the phase of the carrier signal from one phase to another of at least three different relative phases in accordance with a predetermined sequence.
Claim 14
Dependent Claim
65 words
The method of claim 10 wherein the step of generating a band of radio frequency energy for irradiation of the sample to be analyzed includes the step of pulse modulating the intensity of the carrier signal to produce a train of radio frequency pulses such train of pulses having Fourier side band components of radio frequency energy which are utilized for irradiation of the sample.
Claim 15
Dependent Claim
102 words
The method of claim 11 wherein the step of repetitively time scanning, sampling and storing a multiplicity of successive time displaced components includes, the step of time scanning the detected composite resonance signal during the period between successive pulses of the carrier signal energy, and storing and adding respective sampled time displaced composite resonance signal components to those of previous scans to obtain time averaged data in separate respective channels of a memory, and Fourier transforming the read out time averaged signal components from the time domain into the frequency domain to obtain time averaged spectral data concerning the sample under analysis.
Claim 16
Independent Claim
140 words
The method of obtaining magnetic resonance spectrum of a sample under analysis including the steps of: producing a unidirectional polarizing magnetic field enveloping said sample, applying a plurality of time-spaced impulses of driving radio frequency magnetic field to said sample for an experiment time T to produce a series of successive free precession signals from said sample responsive to said driving pulses, demodulating said free precession signals to obtain a series of free induction decay envelope signals, time-averaging discrete segments of said decay signals over the series of successive signals, wherein said step of applying said plurality of time-spaced pulses includes providing said pulses in N i different phases relative to a reference where i is an integer greater than 2, dividing said experiment time T into i equal time increments and arranging said time-spaced pulses in i different sets.
Claim 17
Independent Claim
140 words
The method of obtaining magnetic resonance spectrum of a sample under analysis including the steps of: producing a unidirectional polarizing magnetic field enveloping said sample, applying a plurality of time-spaced impulses of driving radio frequency magnetic field to said sample for an experiment time T to produce a series of successive free precession signals from said sample responsive to said driving pulses, demodulating said free precession signals to obtain a series of free induction decay envelope signals, time-averaging discrete segments of said decay signals over the series of successive signals, wherein said step of applying said plurality of time-spaced pulses includes providing said pulses in N i different phases relative to a reference where i is an integer greater than 2, dividing said experiment time T into i equal time increments and arranging said time-spaced pulses in i different sets.
Claim 18
Dependent Claim
60 words
The method of claim 13 wherein the step of applying a plurality of time-spaced includes selecting the sequence of said time-spaced pulses such that said first set is applied during said first time period, said second set is applied during said second time period, and so on until said i th set is applied in said i th time period.
Claim 19
Dependent Claim
71 words
The method of claim 14 wherein the step of arranging said time-spaced pulses in i different set includes generating the sets such that SET 1 equals N.sub.1, N.sub.2, N.sub.3, ... N.sub.i, N.sub.1, N.sub.2,
N.sub.3 ...
SET 2 equals N.sub.1, N.sub.3, N.sub.5, N.sub.7 ...
SET 3 equals N.sub.1, N.sub.4, N.sub.7, N.sub.10 ...
SET 4 equals N.sub.1, N.sub.5, N.sub.9, N.sub.13 ...
.
.
.
SET i equals N.sub.1, N.sub.1, N.sub.1, N.sub.1 ... .
Claim 20
Dependent Claim
9 words
The method of claim 14 wherein i = 4.
References Cited (Backward Citations)
US3824452A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-07-06 | 1980-01-05 | 1980-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-06 | 1984-01-05 | 1984-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-06 | 1988-01-05 | 1988-07-06 | $7700.00 | Window Closed / Lapsed |