A complete analysis of pulsed NMR signals requires the knowledge of the time dependence of the components of the signal in phase and out of phase with the pulse. In practice, the NMR signal is processed by a pair of (approximately) orthogonal phase‐sensitive detectors, the filtered outputs of which can be sampled, digitized, and stored repetitively. The present paper describes a software technique for correcting these stored signals for the lack of orthogonality of the two phase‐sensitive detectors, the difference between their sensitivities, the overall phase shift in the spectrometer, and the difference between the reference frequency of the spectrometer and the frequency of the center of a reference NMR line. The necessary information is derived (also by software) from measurements performed on a single symmetric NMR absorption line.