Accurate knowledge of a gradient magnetic field waveform is important for the measurement of diffusion coefficients . Diffusion coefficients are determined from the decay between an MR signal affected and an MR signal not affected by gradient pulses. Therefore the waveform of the gradients is essential from the point of view of accuracy. Short ramp times, amplitude of generated gradients and symmetry of positive and negative levels (i.e. an integral of two pulses with the same amplitude and inverse polarity is zero) are desirable.