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In Fourier transform NMR spectroscopy and imaging, a pulse sequence describes a series of
Pulse sequences
in the online textbook
The Basics of NMR
(by Joseph Hornak) Nuclear magnetic resonance
In Fourier transform NMR spectroscopy and imaging, a pulse sequence describes a series of radio frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the uppe ...
pulses applied to the sample, such that the free induction decay is related to the characteristic frequencies of the desired signals. After applying a Fourier transform
A Fourier transform (FT) is a mathematical transform that decomposes functions into frequency components, which are represented by the output of the transform as a function of frequency. Most commonly functions of time or space are transformed, ...
, the signal can be represented in the frequency domain
In physics, electronics, control systems engineering, and statistics, the frequency domain refers to the analysis of mathematical functions or signals with respect to frequency, rather than time. Put simply, a time-domain graph shows how a ...
as the NMR spectrum. In magnetic resonance imaging, additional '' gradient pulses'' are applied by switching magnetic fields that exhibit a space-dependent gradient which can be used to reconstruct spatially resolved images after applying Fourier transforms.
The outcome of pulse sequences is often analyzed using the product operator formalism.
See also
* Spin echo * Insensitive nuclei enhanced by polarization transfer * MRI sequenceReferences
{{reflistExternal links
Pulse sequences
in the online textbook
The Basics of NMR
(by Joseph Hornak) Nuclear magnetic resonance