US3812418A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for the excitation of spin resonances by means of an rf signal having a prescribed amplitude function
Assignee: Spectrospin AG
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Filing: 1971-07-13
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Granted: 1974-05-21
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Expires: 1991-07-13
Abstract
Abstract In the excitation of spin resonances by means of an RF-pulse in a sample arranged in a homogeneous magnetic field for purposes of spin resonance spectrometry, a limitation of the energy of excitation to the frequency range of interest and an essentially constant amplitude of the energy of excitation in that range of frequency is achieved by application of an RF-pulse with an amplitude variable in time which, at least approximately, corresponds to a sine x/x function. Such amplitude function can be generated by a modulation unit which is controlled either by a digital computer with a stored amplitude function or by the output signal of an analog computer solving a suitable differential equation.
Inventors
- 👤 W Tschopp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:59
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/46; G01R33/4616
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
189 words
In a method of excitation of spin resonances for spin resonance spectrometry, including the steps of immersing a spin resonance sample in a unidirectional magnetic field, applying a pulse of RF-energy with frequencies near the Larmor frequencies of the sample, receiving a composite signal produced by the spin moments which precess after the apPlication of the RF-energy and analyzing the components of the received signal, in which the spin moments oriented in said magnetic field are fed such an amount of RF-energy with frequencies at least approximately equal to the Larmor frequencies of the exciting spin moments by means of an RF-signal with an amplitude variable in time corresponding to the frequency spectrum of that signal, that the spin moments are distored by a specific angle Alpha , preferably 90*, relative to the direction of the magnetic field, the improvement comprising the step of using an RF-signal for excitation having a shape so deviating from rectangular that the frequency spectrum of that signal is limited essentially to the range of the Larmor frequencies of the spin moments to be excited and has an essentially constant amplitude within that range.
Claim 2
Dependent Claim
189 words
In a method of excitation of spin resonances for spin resonance spectrometry, including the steps of immersing a spin resonance sample in a unidirectional magnetic field, applying a pulse of RF-energy with frequencies near the Larmor frequencies of the sample, receiving a composite signal produced by the spin moments which precess after the apPlication of the RF-energy and analyzing the components of the received signal, in which the spin moments oriented in said magnetic field are fed such an amount of RF-energy with frequencies at least approximately equal to the Larmor frequencies of the exciting spin moments by means of an RF-signal with an amplitude variable in time corresponding to the frequency spectrum of that signal, that the spin moments are distored by a specific angle Alpha , preferably 90*, relative to the direction of the magnetic field, the improvement comprising the step of using an RF-signal for excitation having a shape so deviating from rectangular that the frequency spectrum of that signal is limited essentially to the range of the Larmor frequencies of the spin moments to be excited and has an essentially constant amplitude within that range.
Claim 3
Dependent Claim
32 words
A method according to claim 1, characterized in that the shape chosen for the amplitude variable with time of the RF-signal is at least approximately a section of a sin x/x function.
Claim 4
Dependent Claim
26 words
A method according to claim 2 with periodically repeated excitation, characterized in that an RF-signal is used for excitation which at least approximately satisfies the sum
Claim 5
Dependent Claim
29 words
A method according to claim 1, characterized in that the RF-energy supplied is selected high enough to decouple all spin resonances falling in the peaked frequency spectrum of RF-excitation.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |