Abstract: An extremely efficient magnet system having a comparatively large angle of aperture can be obtained for magnetic resonance imaging by a reduction of fields of all orders in a common approach affecting active and passive as well as positive and negative oriented coil elements. Passive soft-magnetic ring segments are arranged in two pairs and located within a plurality of larger diameter active magnetic coils. The active coils include a central coil and outer coils wherein the outer coils are smaller than the central coil. The coils are in a helium Dewar vessel and arranged such that the system has an aperture of about 90.degree.. The central active coil may have a larger radius than the smaller outer coils.

Abstract: A charge coupled device for sampling an analog signal voltage. If charge is inputted to a charge coupled device by the so-called phase-referred input method, a minority charge carrier source region (10) in a semiconductor body (1) is clocked in phase with a charge transfer gate (6) so that a metering potential well formed under a metering electrode (4) is alternately filled via a d.c. gate (5) with carriers to a predetermined level and then surplus carriers are drained back via the d.c. gate and the remainder exit via the transfer gate. This mechanism tends to degrade at high frequencies and, in order to improve the high frequency performance, a very short further gate (20) is provided between the d.c. gate and the metering well. This further gate is clocked in antiphase to the source region (10) and the transfer gate (6) so that it creates a rising potential barrier when the surplus carriers are being drained back, thereby isolating the metering well from the source (10) and the d.c.