¹H acquisition with broadband decoupling for two independent nuclei, namely X and Y, can be a normal situation in inverse ¹H-X detected experiments of X,Y-labeled compounds. Thus during ¹H acquisition, decoupling of X and Y (¹³C and ¹⁵N, ...) is performed from two independent channels using a composite pulse decoupling (CPD) scheme in each channel as, for instance, GARP, WURST .... (see decoupling schemes).

Easy implementation on AVANCE spectrometers. A third channel is required.

 For more experimental details see Tutorials: Calibration pulses.

The most standard way to implement heteronuclear decoupling in two independent channels is:

... 2 d1 do:f2 do:f3 ... d12 pl12:f2 pl16:f3 go=2 ph31  cpd2:f2  cpd3:f3 ... d12 do:f2 do:f3 ...

in which:

• go starts data acquisition during an acq period using the acquisition parameters previously defined in eda.
• Broadband heterodecoupling is performed at low power (pl12 and pl16) from the f2 and f3 channels using the cpd2:f2 and cpd3:f3 commands. The composite pulse decoupling schemes to be applied are defined by the acquisition parameters cpdprg2 and cpdprg3 (for instance, garp) and the decoupling conditions are defined by pcpd2 and pcpd3 (90 pulse at pl12 and pl16, respectively). See, for instance, low-power ¹³C 90 pulse calibration for GARP.
• The number after go (=2) defines the loop to be executed. The number of times this loop is repeated is governed by the number of scans (ns).
• ph31 is the receiver phase specified at the end of pulse program and must be cycled in accordance to all pulses involved in the pulse sequence.
• Heterodecoupling is stopped using the do command.