Abstract: A liquid crystal alphanumeric display character is disclosed which includes a central liquid crystal display element. The display character is multiplex-driven and is connected to a plurality of segment lines and a plurality of common lines in a plurality of groups. Provision of the central element allows the segment and common lines to address the display without any of the segment lines having to cross any of the common lines.

Abstract: A speed measurement device for measuring the speed of a ship through the water is disclosed. The device comprises a transmitter circuit and a receiver circuit connected to two transducers T.sub.1, T.sub.2 which are based substantially in the direction of travel of a ship below the water line thereof. Pulse trains are transmitted in both directions between the transducers T.sub.1, T.sub.2 which are received by the receiver circuitry so that a signal is derived indicative of the time taken for the signals to travel both for and against the direction of travel of the ship, this signal being proportional to ship's speed.

Abstract: An angular position sensor comprising a generator coil driven by an oscillator to provide an alternating magnetic field which is symmetrical about an axis, an annular rotor of electrically-conductive or magnetic material such that it distorts the magnetic field around it and arranged so that it is asymmetrical about its axis of rotation and lies outside the equatorial plane of the magnetic field and two sensing coils disposed within the magnetic field. As the rotor 16 rotates about its axis the emfs induced in the sensing coils vary in dependence upon the angular position of the rotor relative to the axis of the undistorted magnetic field.

Abstract: A suspension system suitable for a flux gate compass having compass windings (14) includes a ball joint (4,5,6) which permits both tilt and twist about a vertical axis, and a separate alignment element (16) for causing the windings to follow twisting motion of the fixed structure. The alignment element takes the form of a flexible printed circuit made into a double spiral form and carrying electrical conductors to provide the electrical connections to the windings. A zig-zag shape may be used instead of a spiral. The suspension does not suffer from the geometric imperfections of a Hooke's joint and avoids the need for separate flexible conductors which can interfere with the suspension operation and can break.