Chapter 4. CRAMPS/Multipulse Module Operation
71
VNMR 6.1C User Guide: Solid-State NMR 01-999162-00 C0402
4.12 WaHuHa and WaHuHaHS - MP-Assisted High-Speed
Spinning (4-pulse cycle)
WaHuHa (Figure 25) is the original 4-pulse multipulse sequence. WaHuHAHS is a semi-
windowless version of WaHuHa and is often used in conjunction with high speed spinning.
The sequences are applicable for UNITYplus and
UNITY
INOVA.
Macros
The macros wahuha and wahuhahs convert a S2PUL or FLIPFLOP data set for BR24.
cylmrev converts a data set for quadrature MREV8. All relevant parameters are preserved
if the initial data set is FLIPFLOP, BR24, CYLBR24, MREV8 or CYLMREV.
Parameters
pw is the 90
o
degree pulse-length, in microseconds.
tau is the interpulse delay, in microseconds, including pw. The WaHuHa cycle is 6*tau
long and the WaHuHaHS is 4*tau+2*pw. They are repeated np/2 times to build up a FID.
tauc is the cycle time, in microseconds and is the actual dwell time for the FID. tauc is not
changed and is for information only.
mp_at is the sum of all cycles, in microseconds, and is the true acquisition time. mp_at
is not changed and is for information only.
sw=2e6 turns on the fast ADC without analog filters. sw does not determine the dwell time
(see tauc).
scalesw is a scale factor that converts sw=2e6 to the correctly scaled spectral width.
scalesw=(1.0/tauc*sw)*S where S is the multiple-pulse scale factor for WaHuHa
(0.707 for ideal pulses).
rof1 and rof2 (see 4.9 “FLIPFLOP - Pulse Width and Phase Transient Calibration,”
page 68)
prep
d1
'np'/2 times
pw
tau 2*tau
acq
tau
Figure 25. WaHuHa Pulse Sequence
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