A method and apparatus for improving spectral resolution of an NMR
measurement in the presence of an inhomogeneous magnetic field. According
to one embodiment, a method producing a high resolution nuclear magnetic
resonance (NMR) spectrum for a sample in an inhomogeneous magnetic field
may comprise generating a first magnetic pulse and a second magnetic
pulse, the first and second magnetic pulses being separated in time by a
first time period, during the first time period, generating a gradient
pulse, repeating the steps of generating the first and second magnetic
pulses and generating the gradient pulse N times for different values of
a field strength of the gradient pulse, wherein N is an integer greater
than one, after each second magnetic pulse, acquiring a signal from the
sample, and producing a reconstructed high resolution NMR spectrum from
the acquired signals.