Abstract: Apparatus for controlling the direction of a beam of optical radiation from, say, a laser, includes two prisms of small apex angle independently rotatable about a common axis. A control circuit is responsive to the actual angular positions of the prisms and to inputs indicating the desired beam position to cause the prisms to be moved to the appropriate positions.

Abstract: Apparatus for measuring the extent and sense of relative movement between two objects comprises a reflecting ruled grating carried on one body and optical reading head carried on the other. The reading head includes a light source arranged to produce at least three light beams which are directed at the grating and reflected therefrom onto a mirror twisted about a line parallel to the grating lines. This mirror reflects the light beams onto a different area of the grating from which they are reflected to separate light-sensitive devices. Lenses are used to focus the light beams as required.

Abstract: Data processing apparatus includes a storage circuit or memory, and an addressing circuit for identifying word locations within the storage circuit into and from which a plurality of information items are to be written and read, respectively. Further, there is included an encoding circuit for encoding at least a part of each information item in one-out-of-n code, illustratively. In turn, the encoded part is successively shifted by a shift circuit so that it is stored in the storage circuit in a manner that the stored information in each word location has a bit order different from that order of any other information item as stored in the storage circuit. A translating or de-skewing circuit is provided for shifting the encoded data items as read out from the storage circuit in a direction opposite to that imparted by the first noted shift circuit.

Abstract: A semiconductor device having an ohmic contact including a metal layer of molybdenum or tungsten on a first polycrystalline silicon layer, is provided with a second polycrystalline silicon layer on the metal layer, to prevent the subsequent oxidation of the metal layer.

Abstract: A servo control system comprising, in a feedback loop, means for providing an error signal representing the difference between desired and actual conditions of a controlled system, and means responsive to said error signal to produce a control signal for the controlled system; the control system also comprising means for injecting a predetermined disturbance signal into the loop, and means responsive to a comparison of said disturbance signal and a loop response signal for varying gain in said loop.

Abstract: A communication system for communicating between a central control unit and a plurality of controlled units, all interconnected by a single communication channel, wherein communication is time multiplexed with control words being transmitted in each direction during each time interval allocated to each separate controlled unit. The control words are transmitted during half-cycles of a periodic clock signal of one polarity, while data from the controlled units may be transmitted to the central control unit only during half-cycles of the periodic signal of the opposite polarity.

Abstract: A projectile fuze contains a radio receiver, an oscillator, a counter and detonation means activated by an output signal from the counter. After firing the oscillator is started for a unit time period defined by successive signals transmitted to the projectile from a transmitter. The number of oscillations counted in the unit time period is multiplied by the number of unit time periods until detonation, calculated from range data, and transmitted to the projectile to set a counting limit for the counter before it produces an output signal. The signal containing the range data is used to clear the counter and restart the oscillator and may be used to render the radio receiver unresponsive to further signals. The projectile may have a booster or air-brake which is operated in flight by means of a second counter output signal or an output signal from an additional counter.

Abstract: Semiconductor devices are mounted on corresponding lead frames by being inserted into apertures of a masking member in a desired registration with the lead frame strip.

Abstract: A measuring system includes a scale grating carried on one of two relatively movable bodies and an index grating carried on the other. The scale grating is illuminated directly in such a way that light passing from it to the index grating is at least partially diffuse. Detector means are provided to respond to the resulting spatially periodic distribution of illumination.

Abstract: Currents greater than predetermined amount are prevented within a circuit arrangement by connecting the electrical supply to at least one conductor via a diode and a transistor, with the diode and the base-collector junction of the transistor in series between the conductor and the supply, and with the emitter connected via a resistor to a point maintained at an appropriate reference potential level, the transistor being in a grounded-base configuration, with the maximum possible collector current defined by the maximum possible emitter current.

Abstract: Apparatus for controlling deformation of an elongate member, such as a lattice girder, comprises a torque transmitting member, such as a hollow cylindrical tube, extending for the length of the girder coaxially with its longitudinal axis and fixed at one end to one end of the girder. The cylinder is free to rotate relative to the girder at its other end and is connected by hydraulic actuators to be rotated relative to the girder in response to the measurement of rotation between the ends of the girder. The relative rotation of the tube transmits torque to the fixed end and resists deformation of the girder.

Abstract: An inverter has a bipolar transistor and a field-effect transistor. The base gate electrodes are connected to the inverter input, and the collector and source electrodes are connected to the inverter output. The transistors are in series between supply rails. The lower of two possible input voltage levels causes the bipolar transistor to be switched OFF and the field-effect transistor to be switched ON, and the higher possible input voltage level causes the bipolar transistor to be switched ON and the field-effect transistor to be switched OFF. Base current level control is provided for discharging parasitic capacitance across the bipolar transistor when the latter is switched ON.

Abstract: A spring loading system achieves substantially zero-rate by winding an unstressed, say flat, spring strip onto a former of constant curvature so as to pass from the unstressed state through a region of predetermined shape to conform with the former. The net energy expended/released in winding/unwinding the strip is directly related to the amount of strip wound onto/off the former, whatever the total length of strip wound. The system is coupled to a driven member by an inextensible string wound on the former in opposition to the spring which is held in tension by the torque exerted on the former by the wound spring.

Abstract: A semiconductor device having a plurality of constituent components within a semiconductor body such that the device in combination with one of a plurality of different possible metallization patterns of conductors forms a desired circuit arrangement, is provided in a semiconductor body having an epitaxial layer of one conductivity type on a substrate of the same conductivity type and suitable to be employed as a conductive plane, and is manufactured by a method which includes the diffusion step of providing simultaneously within the epitaxial layer regions of opposite conductivity type of the constituent components of the device and a network of conductive tracks, it being possible, for example, for the device to include bipolar transistors of the so-called collector-diffusion-isolation construction or isoplanar construction.

Abstract: In a non-gold-doped TTL device to be energized by a potential supply of at least 4.5 volts; the charge carrier concentration within a NPN multi-emitter input transistor is reduced by connecting together the base and the collector; undesirable emitter-to-emitter transistor action is prevented, by reducing the inverse current gain factor of the input transistor, and preventing this transistor from saturating, by providing a diode within the phase splitter stage, to ensure that the input threshold level of the device is at least two forward biased diode potentials above the least positive supply rail; and providing a suitable pull-up stage for the output transistor, which pull-up stage may comprise a modified Darlington pair of transistors, including a resistor between the emitter of the first transistor and the base of the second transistor, and a resistor between the base and the emitter of the second transistor.

Abstract: In a surface inspection system a detector responds to light received from the surface to give a detector signal including disturbances due to surface faults, and includes an equalizer circuit to control the gain of a photomultiplier, and therefore signal amplitude, in response to a peak level detector, to control the level of the signal in relation to the amplitude of the disturbances and a band-pass filter to compensate for variations in the signals due to changes in the optical gain of the detector. The equalizer circuit is an amplifier and the control is achieved by way of feedback and feedforward control loops. In a modification the system may comprise a row of detectors and the equalizer circuit may be arranged to accommodate changes in the amount of light received at the junctions of detectors.

Abstract: An assembly includes two members, such as gyroscope gimbals, capable of limited relative rotation, and a flat, flexible conductor strip secured to the members, the axis of the strip extending between its securing positions wholly extending towards the common axis of rotation of the members the strip axis lying in a plane with the members at their mean relative orientation, and twisting as the members rotate therefrom.

Abstract: A security system comprises electronic means for generating a group of pulses of predetermined frequency, which group has a unique identity specified by the particular durations of its constituent pulses; means for transmitting that group of pulses; means for receiving that group of pulses; and means responsive to that received group of pulses only when it has said unique identity. Preferably the pulses are bursts of high frequency waves, and the means responsive to received pulses includes means for establishing tolerance intervals for the ends of corresponding pulses.

Abstract: A multiplier circuit arrangement comprises two parallel paths for the same signal, one of the paths being associated with signal level adjusting means; and means responsive to inbalance of d.c. components including any in said parallel paths, the inbalance being in accordance with a d.c. signal in a third signal path, to produce a control signal for varying the signal level adjusting means to reduce the imbalance, so that a.c. components in said parallel paths will be unbalanced to an extent proportional to the d.c. signal in said third path.

Abstract: In a follow-up servo system for the electrical control of a friction clutch of, say, a motor vehicle from the throttle control by way of an electro-mechanical actuator, with automatic take-up of the wear of the mating friction surfaces, whenever the clutch plate (i.e. the axially-movable part) is in its fully-engaged (FE) position with respect to the cooperating axially-fixed part a signal is repetitively derived to represent the corresponding just-touching (JT) position of the plate under the then conditions of wear. To this signal is added a signal from the throttle control within a range corresponding to the JT-FE range of the plate, thereby forming a demand signal corrected for wear. From a comparison of it with a measurement signal representing the actual position of the plate an error signal is derived for application to the actuator in the appropriate sense.