for the gradient power supplies computer 401 also performs data processing such as fourier transforms image reconstruction data filtering image display and storage functions most of which are well known and do not form an intrinsic part of the present invention transmitter and receiver rf coils may be configured as a single coil alternatively two separate coils that are electrically orthogonal may be used the latter configuration has the advantage of reduced rf pulse breakthrough into the receiver during pulse transmission in both cases the coils are orthogonal to the direction of the static magnetic field b o produced by magnet 428 the coils are isolated from the remainder of the system by enclosure in an rf shielded cage three typical rf coil designs are illustrated in the aforementioned co pending application ser no 345 444 filed feb 3 1982 as fig1 a 11b and 11c therein all of the coils depicted therein produce rf magnetic fields in the x direction and the coil designs illustrated in fig1 b and 11c are suitable for magnetic geometries for which the axis of the sample chamber is parallel to the main field b o as shown in fig1 of the instant specification the coil design illustrated in fig1 a is applicable to geometries for which the sampler chamber axis is perpendicular to main field b o magnetic field gradient coils 416 418 and 420 are necessary to provide the g x g y and g z gradient fields respectively in the multiple angle projection reconstruction and spin warp methods described above the gradient fields should be monotonic and linear over the sample volume nonmonotonic gradient fields can cause a degradation in the nmr signal data known as aliasing which can.