Simulation of Multipulse Tune-up Sequences

A general-purpose method for the simulation of a spin- 1 2 response to a multipulse train is presented. This is used to calculate the results of tune-up sequences often used in spectrometer calibration and characterization. The method is capable of including effects arising from RF and magnetic field inhomogeneities, finite amplitude and duration of pulses, and spin relaxation for T₁ = T₂. The pulses may also be of arbitrary shape in amplitude and phase, allowing for the inclusion of phase glitch and finite rise-time effects. Results are presented for the usual tune-up sequences and in particular for the Haubenreisser-Schnabel sequence for tuning the transmitter phase. The effects of symmetric and asymmetric phase glitch, field inhomogeneities, etc., are illustrated by Fourier transforming the data array. This procedure produces an antiphase doublet with a splitting proportional to the transmitter phase. The accuracy of this technique in measuring small-angle phase shifts is discussed.