Figure 12.
Time and frequency domain features of broadband decoupling. (A) In most realistic cases the length of the decoupling RF pulses span several dwell times Δ τ, such that the effects of heteronuclear scalar coupling evolution are not refocused until the end of the pulse. As a result part of the scalar coupling evolution is captured by the data acquisition points covering the length of the RF pulse. (B) These small modulations give rise to so-called decoupling or modulation side bands following Fourier transformation, potentially obscuring other, smaller resonances. The decoupling sidebands necessarily also lead to a reduction in the peak height of the main decoupled resonance (100% represents the maximum intensity in the case of perfect on-resonance CW decoupling).