ABSTRACT
In 1982, the modulated-gradient technique was introduced to avoid these restrictions and to simplify the problems of deconvolution. A second computer for gradient control is connected with the zero-plane drive unit of the tomography unit. Differences in the electrical parameters of the gradient coils, the two high-power amplifiers and the interaction between the two coils, the cavity, and the pole pieces can change the phase between the two modulated fields generating the field gradient. Further advantages of modulated gradients consist in direct optimization of spectrometer parameters to improve the signal-to-noise ratio and the feasibility of using higher derivatives for resolution enhancement. The advantages of the modulated gradient technique are the direct measurement of the spatial distribution and the possibility of measuring the electron paramagnetic resonance (EPR) spectrum in a selected region of the sample. The EPR spectrometer that is used in the experiments operates in the continuous wave mode and is connected to a computer for data acquisition.
