Abstract: A bearing assembly is provided in which bearing preload is exerted by both high and low rate non-linear springs, the low rate springs being substantially collapsed when the preload is applied. A shaft is mounted in two angular contact ball bearings contained in a housing with the bearing outer races maintained a fixed distance apart. The springs are two sets of hard and soft spring washers in tandem each set acting on a respective inner bearing race through the intermediary of a respective thrust member. Mechanical stop faces engage in the event of severe axial loading to prevent such excessive loads from being transmitted through the bearings. The amount of preload applied can be discerned from the width of gaps existing between faces on the thrust members and respective end faces on the housing.

Abstract: An auxiliary aerodynamic or hydrodynamic control assembly is provided for a vehicle, such as a guided missile, travelling in a fluid medium, which assembly comprises a number of, say three, control surfaces each carried at the inner end of an arm that is mounted at its outer end on a pivot situated at or near the periphery of a housing of circular cross section, the arm pivots being spaced equidistantly around said periphery. In its neutral or undeflected position each arm extends radially inward from the respective pivot and the control surface it carries, which is generally in the form of a circular arc centered on the pivot, lies retracted wholly within the housing. Angular movement of each arm about its pivot in one direction or the other causes one or the other half of the respective control surface to project from the housing. Different combinations of movement of the several control surfaces give rise to moments in roll, pitch or yaw.

Abstract: Line-scanning equipment, especially for aerial photography of terrestrial scenes, has an infra red scanner which causes the scanning beam to sweep repeatedly across the scene in the direction at right angles to the direction of travel of the aerial vehicle. As the angle of departure of the scanning beam from the vertical increases the strip of the scene being viewed in any one scanning cycle widens progressively so that the total strip has the shape of a `bow-tie`. A mechanically-actuated shutter is provided to restrict the recorded image to only that part of the recording beam information which is derived from a parallel-sided ground area within the `bow-tie`; and a correcting lens is employed to ensure that the final image is parallel-sided.

Abstract: In an imaging system, a radiation detector which scans an image has it output amplified by a D.C. preamplifier and to neutralize low frequency noise and drift the preamplifier output is amplified by a further D.C. amplifier having a feedback capacitor and to which a reference voltage is applied the further amplifier output being applied as a second input to the preamplifier. A sample and hold switch controls the application of the preamplifier output to the further amplifier, this switch being closed only during the dead times between consecutive scan lines.

Abstract: In an optical scanning system having a rotary scanner with multiple reflectors, which scanner images a light-responsive detector and moves that image repeatedly across the flat image field of an objective to generate a scanning raster, an optical corrector is mounted in the beam imaging the detector to correct for the fact that the detector image moves in a curved path. The optical corrector has a stepped surface such as to adjust the detector image incrementally during a scan, in the direction normal to the plane of the image field of the objective, so as to make the detector image motion substantially parallel to said image field.

Abstract: Scanning apparatus for scanning a field of view having a multidetector array which traverses the field of view, the detectors of which are sensitive to variations in electromagnetic radiation wherein each detector is a.c. coupled to an amplifier in a respective video channel and at the end of each scan the gains of the amplifiers in the said channels are equalized one with another.

Abstract: In a mechanism for controlling the movements of a dirigible scanning head, movement about one of three orthogonal axes is imparted to the head by means of a pair of flexible straps which are fastened to the head at opposite sides of said one axis and extend along a part-circular track at the back of the head that is centered on said one axis. The straps are wrapped around respective rollers mounted on a carrier that is itself displaceable in a direction generally along the track by a coupling to an endless flexible band driven by an electric motor-drive. The straps and the drive means for them are carried by the head for rotation with the head relatively to a support member about a second of the three axes.The straps support conductors for carrying electrical supplies to those units of the scanning head that so require.

Abstract: A digital memory is configured as a hierarchical system with at least three levels. The first level consists of a main bus and interfacing for one or more main memory units; the second level consists of a separate second level bus in each main memory unit with a plurality of memory frames independently interfaced to each bus; and the third level consists of a separate third level bus in each memory frame with a plurality of memory storage blocks independently interfaced to each bus. Virtual addressing is employed in which the whole of each address is decoded in the individual memory block which includes for the purpose soft-ware settable registers containing identification numbers.

Abstract: In an automatic inventory system for crops, especially tree-borne crops, an airborne television camera views the area being surveyed and delivers an analogue video signal which is converted into a series binary digital signal by a level detector. The serial digital signal is received in a shift register that delivers a parallel digital output to a computer. The shift register is controlled by shift pulses derived from a pulse generator that has the video signal applied to it to maintain the pulses in synchronism with the camera operation. The computer receives the information from the shift register a frame at a time and determines from it parameters such as the average size, and spacing of crop-bearing trees and their numbers.

Abstract: In a shaft angle encoder, an optical system translates the shaft angular displacement into a difference of two optical path lengths and that difference is measured by interferometry. Light from a monochromatic source is split and both the transmitted and reflected beams are passed along separate paths through an optical component that moves angularly with the shaft and varies the lengths of the separate paths differentially according to the shaft angular displacement. The transmitted and reflected beams are then recombined and the interference fringes in the recombined beam sensed by a detector.

Abstract: An optical scanning system has a dirigible head of generally spherical shape mounted on a support body for scanning through a substantially hemispherical field of view, and optical lenses, a scanner rotor and drive motor therefor, and a cryogenically-cooled detector element array are all mounted within the confines of the dirigible head. The head has a primary objective lens in its outer shell and further lenses are mounted within the head in an adjustable holder enabling different lenses to be brought into alignment with the objective lens. The scanner rotor is generally annular and rotates about an axis oblique to the optical axis of the objective lens; it comprises a multi-faceted reflector receiving the image beam from the lens system and reflecting it laterally on to the detector array.

Abstract: In a binary parallel complementing L.S.I. adder, a C-MOS transmission gate is provided in each stage with its input and output directly connected to the carry in and carry out leads of the stage. The gate is switched by complementary control bits derived by stage input logic operating on the bits to be summed, whereby very fast passage of a carry through the stages is achieved. The transmission gate consists of p- and n- channel MOS transistors with their sources connected in common to the input and their drain electrodes likewise connected in common to the output.