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Enh: New options in make_arbitrary_rf.py for adiabatic pulses #143

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Oct 31, 2023
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Enh: New options in make_arbitrary_rf.py for adiabatic pulses #143

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11 changes: 9 additions & 2 deletions pypulseq/make_arbitrary_rf.py
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ def make_arbitrary_rf(
delay: float = 0,
dwell: float = 0,
freq_offset: float = 0,
no_signal_scaling: bool = False,
max_grad: float = 0,
max_slew: float = 0,
phase_offset: float = 0,
Expand All @@ -42,8 +43,12 @@ def make_arbitrary_rf(
Bandwidth in Hertz (Hz).
delay : float, default=0
Delay in seconds (s) of accompanying slice select trapezoidal event.
dwell : float, default=0
Temporal sampling step of waveform. If set to 0, will use `system.rf_raster_time`.
freq_offset : float, default=0
Frequency offset in Hertz (Hz).
no_signal_scaling : bool, default=False
If set to True no rescaling of the RF amplitude will happen. E.g. for adiabatic pulses.
max_grad : float, default=system.max_grad
Maximum gradient strength of accompanying slice select trapezoidal event.
max_slew : float, default=system.max_slew
Expand All @@ -55,7 +60,7 @@ def make_arbitrary_rf(
return_gz : bool, default=False
Boolean flag to indicate if slice-selective gradient has to be returned.
slice_thickness : float, default=0
Slice thickness of accompanying slice select trapezoidal event. The slice thickness determines the area of the
Slice thickness (m) of accompanying slice select trapezoidal event. The slice thickness determines the area of the
slice select event.
system : Opts, default=Opts()
System limits.
Expand Down Expand Up @@ -90,7 +95,9 @@ def make_arbitrary_rf(
signal = np.squeeze(signal)
if signal.ndim > 1:
raise ValueError(f"signal should have ndim=1. Passed ndim={signal.ndim}")
signal = signal / np.abs(np.sum(signal * dwell)) * flip_angle / (2 * np.pi)

if not no_signal_scaling:
signal = signal / np.abs(np.sum(signal * dwell)) * flip_angle / (2 * np.pi)

N = len(signal)
duration = N * dwell
Expand Down