Timing diagram for an MRI spin echo pulse sequence.
Graphical representation of a pulse sequence for a homonuclear NOESY experiment. The three bars represent three 90° pulses.
An INEPT NMR pulse sequence for a heteronuclear experiment. The thin bar denotes a 90° pulse, while the thick bar denotes a 180° pulse. INEPT is a common building block of NMR experiments to improve 15N signal.[1]

In Fourier transform NMR spectroscopy and imaging, a pulse sequence describes a series of radio frequency 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, the signal can be represented in the frequency domain 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.[2]

The outcome of pulse sequences is often analyzed using the product operator formalism.

See also

References

  1. ^ M H Levitt (2008). Spin Dynamics. John Wiley & Sons Ltd. ISBN 978-0470511176.
  2. ^ Bernstein, M.A.; King, K.E.; Zhou, X.J.; Fong, W. (2004). Handbook of MRI Pulse Sequences. Retrieved 2008-04-08.


Allikas: https://en.wikipedia.org/wiki/Pulse_sequence
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