sigpy.mri.rf.adiabatic.hypsec

sigpy.mri.rf.adiabatic.hypsec(n=512, beta=800, mu=4.9, dur=0.012)[source]

Design a hyperbolic secant adiabatic pulse.

mu * beta becomes the amplitude of the frequency sweep

Parameters:
  • n (int) – number of samples (should be a multiple of 4).
  • beta (float) – AM waveform parameter.
  • mu (float) – a constant, determines amplitude of frequency sweep.
  • dur (float) – pulse time (s).
Returns:

2-element tuple containing

  • a (array): AM waveform.
  • om (array): FM waveform (radians/s).

References

Baum, J., Tycko, R. and Pines, A. (1985). ‘Broadband and adiabatic inversion of a two-level system by phase-modulated pulses’. Phys. Rev. A., 32:3435-3447.