US3909705A
Expired / Lapsed
US
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Method of and device for recording spin resonance spectra
Assignee: Spectrospin AG
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Filing: 1973-07-30
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Granted: 1975-09-30
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Expires: 1993-07-30
Abstract
Abstract For recording spin resonance spectra the spins of a specimen located in a magnetic field are excited with a pulse-modulated radio-frequency signal (excitation signal). The signal furnished by the excited spins (received signal) in the pulse intervals of the excitation signal is pulse-modulated in such a manner that it is suppressed at least for the duration of the pulses of said excitation signal and that its phase changes by 180* from pulse to pulse. In this way the energy of the receiving signal is distributed to fewer frequency components and a substantial improvement of the signal-to-noise ratio is achieved. A device for performing the method comprises a radio-frequency generator for generating the carrier frequency, a pulse generator for generating a first pulse train with a predetermined pulse repetition frequency as modulation frequency, a first modulator furnishing a pulse- modulated radio-frequency signal coupled to said radio-frequency generator and said pulse generator, a specimen holder coupled to said modulator and located in a magnetic field, and a superheterodyne receiver coupled to said specimen holder, which superheterodyne receiver contains a modulating device to which a second pulse train, whose pulses fall into the intervals between the pulses of said first pulse train and have an alternating polarity, is applied by said pulse generator to modulate the signal received from said specimen holder.
Inventors
- 👤 Werner Tschopp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:29
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/46; G01R33/4616; G01R33/28; G01R33/32; G01R33/36; G01R33/3607
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
101 words
A method of recording spin resonance spectra, comprising periodically exciting the spins of a specimen located in a magnetic field with a pulse-modulated radio-frequency excitation signal of high pulse repetition frequency such that the pulses follow one another so closely that only a specific spin type is excited, processing the signal furnished by the excited spins in the pulse intervals of the excitation signal in such a manner that said signal is suppressed at least for the duration of the pulses of said excitation signal and that its phase position changes 180* from pulse to pulse, and detecting the processed signal.
Claim 2
Independent Claim
101 words
A method of recording spin resonance spectra, comprising periodically exciting the spins of a specimen located in a magnetic field with a pulse-modulated radio-frequency excitation signal of high pulse repetition frequency such that the pulses follow one another so closely that only a specific spin type is excited, processing the signal furnished by the excited spins in the pulse intervals of the excitation signal in such a manner that said signal is suppressed at least for the duration of the pulses of said excitation signal and that its phase position changes 180* from pulse to pulse, and detecting the processed signal.
Claim 3
Dependent Claim
54 words
A method as claimed in claim 1, characterized in that the spins are excited with unchanging phase with the carrier frequency of the excitation signal and that the first side bands of the phase-alternating modulated signal, which are spaced from said carrier frequency at a distance corresponding to half the modulation frequency, are processed.
Claim 4
Dependent Claim
104 words
A method as claimed in claim 1, characterized in that the excitation signal is also pulse-modulated with a 180* change in phase position from pulse to pulse and the spins are excited with a side band of the excitation signal spaced from the carrier frequency at a distance corresponding to 1.5 times (2.5 times, 3.5 times . . . ) the modulation frequency and that those side bands of the incoming signal are processed which are spaced from the carrier frequency at a distance corresponding to the simple (double, triple . . . ) or double (triple, quadruple . . . ) modulation frequency.
Claim 5
Dependent Claim
54 words
A method as claimed in claim 1, characterized in that the signal modulated with phase alternation is additionally amplitude-modulated with a sine wave whose frequency is equal to half the pulse repetition frequency of the pulse modulation and whose zero positions coincide at least approximately with the midpoints of the interspaces beTween successive pulses.
Claim 6
Independent Claim
238 words
A device for recording spin resonance spectra, comprising a radio-frequency generator for generating a carrier frequency, a pulse generator for generating a first pulse train with a predetermined pulse repetition frequency forming a modulation frequency, a first modulator connected to said radio-frequency generator and said pulse generator for furnishing a pulse-modulated radio-frequency output signal, a specimen holder coupled to said modulator and located in a magnetic field and a superheterodyne receiver coupled to said specimen holder, characterized in that said superheterodyne receiver contains a modulating device connected to said pulse generator to receive a second pulse train whose pulses fall into the intervals between the pulses of said fiest pulse train and have no alternating polarity to modulate the incoming signal from said specimen holder, and in which the receiver further comprises first mixer means for converting the incoming signal to within an intermediate-frequency range, and the modulating device comprises a second and a third modulator, of which one is located in the path of the intermediate-frequency signal after said first mixer means and the other in the path of the heterodyne signal applied to said first mixer means and means for applying second and third pulse trains to said second and third modulators, both of said second and third pulse trains having the same pulse repetition frequency, the same pulse duty factor and the same phase position, but only one being comprised of pulses of alternating polarity.
Claim 7
Independent Claim
238 words
A device for recording spin resonance spectra, comprising a radio-frequency generator for generating a carrier frequency, a pulse generator for generating a first pulse train with a predetermined pulse repetition frequency forming a modulation frequency, a first modulator connected to said radio-frequency generator and said pulse generator for furnishing a pulse-modulated radio-frequency output signal, a specimen holder coupled to said modulator and located in a magnetic field and a superheterodyne receiver coupled to said specimen holder, characterized in that said superheterodyne receiver contains a modulating device connected to said pulse generator to receive a second pulse train whose pulses fall into the intervals between the pulses of said fiest pulse train and have no alternating polarity to modulate the incoming signal from said specimen holder, and in which the receiver further comprises first mixer means for converting the incoming signal to within an intermediate-frequency range, and the modulating device comprises a second and a third modulator, of which one is located in the path of the intermediate-frequency signal after said first mixer means and the other in the path of the heterodyne signal applied to said first mixer means and means for applying second and third pulse trains to said second and third modulators, both of said second and third pulse trains having the same pulse repetition frequency, the same pulse duty factor and the same phase position, but only one being comprised of pulses of alternating polarity.
Claim 8
Dependent Claim
46 words
A device as claimed in claim 5, characterized in that the modulating device includes means for effecting amplitude modulation of the incoming signal to which a sine wave in synchronism with the second pulse train is applied by the pulse generator with half pulse repetition frequency.
Claim 9
Dependent Claim
67 words
A device as claimed in claim 6, characterized in that first and second phase detectors are connected in series to the output of said modulating device and means for applying a reference signal having the frequency of the excitation signal converted to within the intermediate-frequency range to the first phase detector, while a reference signal having half the modulation frequency is applied to the second phase detector.
Claim 10
Dependent Claim
39 words
A device as claimed in claim 7, characterized in that the reference signal applied to the first phase detector is produced by a controlled oscillator to which control signals are applied by the radio-frequency generator and the pulse generator.
Claim 11
Dependent Claim
42 words
A device as claimed in claim 8, characterized in that phase shifters are located in the branches serving to apply the heterodyne and reference signals, said phase shifters permitting an optimum adjustment of the phase positions of said heterodyne and reference signals.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |