A programmable pulse generator is described for NMR spectrometers. The pulse generator can operate either in a single cycle mode where up to 16 pulses can be given sequentially or, in the double cycle mode, a programmable number (⩽15) of these pulses can be repeatedntimes (n⩽99) before the rest of the 16 pulses are completed. The length of all these pulses can be programmed, manually or by computer. As an example the programming of the pulse generator for a multiple contact proton enhanced13C NMR experiment is given.