Discrete analysis of stochastic NMR.II

Wong, Scott T.; Rods, M.S; Newmark, Richard D.; Budinger, T.F.

doi:10.1016/0022-2364(90)90005-t

Cited by 2 publications

(1 citation statement)

References 8 publications

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“…In the early seventies, Ernst [8], Kaiser [9], and Ziessow and Blümich [10] proposed the use of stochastic excitation (i.e., pseudo-random excitation) as an alternative to coherent pulsed excitation. More systematic introductions have been published elsewhere [11][12][13][14][15][16][17]. Stochastic excitation studies have also been reported in pulsed EPR by Prisner and Dinse [18].…”

Section: Introductionmentioning

confidence: 96%

Stochastic excitation and Hadamard correlation spectroscopy with bandwidth extension in RF FT-EPR

Pursley

Kakareka

Salem

et al. 2003

Journal of Magnetic Resonance

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The application of correlation spectroscopy employing stochastic excitation and the Hadamard transform to time-domain Fourier transform electron paramagnetic resonance (FT-EPR) spectroscopy in the radiofrequency (RF) band is described. An existing, time-domain FT-EPR spectrometer system with a Larmor frequency (L(f)) of 300 MHz was used to develop this technique by incorporating a pseudo-random pulse sequence generator to output the maximum length binary sequence (MLBS, 10- and 11-bit). Software developed to control the EPR system setup, acquire the signals, and post process the data, is outlined. The software incorporates the Hadamard transform algorithm to perform the required cross-correlation of the acquired signal and the MLBS after stochastic excitation. To accommodate the EPR signals, bandwidth extension was accomplished by sampling at a rate many times faster than the RF pulse repetition rate, and subsequent digital signal processing of the data. The results of these experiments showed that there was a decrease in the total acquisition time, and an improved free induction decay (FID) signal-to-noise (S/N) ratio compared to the conventional coherent averaging approach. These techniques have the potential to reduce the RF pulse power to the levels used in continuous wave (CW) EPR while retaining the advantage of time-domain EPR methods. These methods have the potential to facilitate the progression to in vivo FT-EPR imaging of larger volumes.

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Section: Introductionmentioning

confidence: 96%

Stochastic excitation and Hadamard correlation spectroscopy with bandwidth extension in RF FT-EPR

Pursley

Kakareka

Salem

et al. 2003

Journal of Magnetic Resonance

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BURST excitation pulses

Heid

1997

Magnetic Resonance in Med

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A theory of optimum burst excitation is developed in the framework of the Shinnar-LeRoux spinor formalism. An N pulse RF train of constant or linear phase cannot improve on an average echo strength of M0/N, and a phase modulation of the pulse train is necessary to improve the signal yield to the theoretical maximum value M0 square root of N. Several methods are presented yielding pulse trains of nearly optimum average amplitude for arbitrary N. It is shown that RF phase spoiling can be analyzed with the same framework. The presented pulse trains may also be useful when ultrawide spectrum hard pulses are required, but only limited RF power is available, e.g., for NMR experiments in extremely inhomogeneous B0 fields.

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Discrete analysis of stochastic NMR.II

Cited by 2 publications

References 8 publications

Stochastic excitation and Hadamard correlation spectroscopy with bandwidth extension in RF FT-EPR

Stochastic excitation and Hadamard correlation spectroscopy with bandwidth extension in RF FT-EPR

BURST excitation pulses

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