This paper describes the design of a precision, programmable impulse generator capable of producing repetitive impulse trains of accurately defined parameters, selectable over a wide range. The generator was conceived for the specific purpose of gating the audio modulation of the applied magnetic field in an HA 100 Varian NMR spectrometer. The basic circuit is much more general, however, and may be used for the generation of a wide variety of impulse trains. The present configuration is capable of producing repetitive trains of one &pgr; pulse followed by several equidistant 2&pgr; pulses. The width of these pulses, their number, their separation, and the repetition rate of the sequence are independently selectable. The selections may be made manually or by remote control from an on‐line digital computer. All times are increments of a basic clock period, derived in our case from the 16.7 MHz crystal oscillator of the spectrometer. Construction is modular and TTL integrated circuits are used throughout for simplicity.