Abstract: A saddle coil for multiple tuned response is realized by a segmented sequence of first LC elements each tuned to exhibit a low impedance at .omega..sub.1 and a second set of LC elements, each tuned to exhibit a low impedance at .omega..sub.2, at least some of said first set of LC elements having one of said second LC elements in parallel therewith.

Abstract: A double-tuned circuit is realized from 1/2.lambda..sub.1 transmission lines for connecting a pair of inductors in series at a first frequency and in parallel for a second frequency where said first and second frequencies are in the ratio of a power of two.

Abstract: Synchronous apparatus capable of a variety of operational states responds to a sequence of digital control words, each specifying a desired state and persistence time of the state. The control words are furnished to the apparatus from a self-clocked FIFO in accord with the persistence code. A selected sub-sequence of digital control words in ROM is placed in an auxiliary FIFO upon detection of a corresponding token in the main sequence and control is passed to the auxiliary FIFO to furnish the sub-sequence to the apparatus. At the conclusion of the sub-sequence control is returned to the main FIFO and the main sequence is resumed.

Abstract: Synchronous apparatus capable of a variety of operational states responds to a sequence of digital control words, each specifying a desired state and persistence time of the state. The control words are furnished to the apparatus from a self-clocked FIFO in accord with the persistence code. A selected sub-sequence of digital control words in ROM is placed in an auxiliary FIFO upon detection of a corresponding token in the main sequence and control is passed to the auxiliary FIFO to furnish the sub-sequence to the apparatus. At the conclusion of the sub-sequence control is returned to the main FIFO and the main sequence is resumed.

Abstract: A sample cavity resonator for NMR spectroscopy contains a pair of diametrically opposed paraxial post structures approximating a single turn inductance about the axially positioned sample. The posts are separately excited in 180 degree relative phases by respective coupling loops spaced between the corresponding post and the cavity wall. A slideable piston structure capacitively couples to the posts and provides cavity tuning.

Abstract: A magnetic resonance catheter system combining with a magnetic resonance imaging device, a catheter including a coil winding for exciting a weak magnetic field at the tip of the catheter. The location of the catheter tip is thereby obtained in cooperation with the magnetic resonance imager.

Abstract: A Fourier transform NMR spectrometer incorporates a digital acquisition processor which provides a sequence of gating states specifying properties of the excitation, decoupling, and homogeneity spoiling pulses, lock channel operation and the like. Each gating state, together with the selected persistance time for the corresponding state, occupies one of a sequence of words supplied by the acquisition processor to a FIFO buffer. Timing control means, initialized from the persistance time portion of the current FIFO word, determines the time interval during which said gating state information is available at an output port, after which the next sequential FIFO word is advanced to the output port. NMR response is accumulated and averaged in a dual port fast semiconductor memory. The semiconductor memory is independently accessible to a host computer through a direct memory port.