Wideband, uniform rate, smooth truncation

Hyperbolic Secant Inversion Pulses and Wideband Uniform Rate Smooth Truncation... 

Siegel et al. showed that enhancement of the CT can also be obtained using hyperbolic secant (HS) pulses to invert selectively the STs [74], Unlike the DFS waveform, whose frequency sweep is generated by a constant rf-pulse phase while modulating the amplitude, the HS pulse utilizes both amplitude and phase modulation, yielding an enhancement exceeding that obtained by DFS or RAPT [61, 74, 75]. Most recently, the pulse sequence called wideband uniform-rate smooth truncation (WURST) [76] was introduced to achieve selective adiabatic inversion using a lower power of the rf-field than that required for the HS pulses [77,78]. One of its applications involved more efficient detection of insensitive nuclei, such as 33S [79]. 

Very recently, the WURST-QCPMG sequence was developed to achieve uniform excitation of quadrupolar nuclei across very wide bandwidth using frequency-sweep chirped pulses [86]. The WURST (wideband uniform-rate smooth truncation) pulses provide broadband excitation. Integrating the WURST pulses with QCPMG results in the WURST-QCPMG method, which has proven to be a highly efficient approach for acquiring ultra-wideHne NMR spectra [74]. 

WURST Wideband, uniform rate and smooth truncation (broadband decoupling sequence) 9.2... 

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