Abstract: Motion picture film transport of the kind used in a telecine apparatus uses a common film lacing path between a picture gate and a sound gate for films of different gauges. An audio delay circuit delays the audio signal generated at the sound gate for at least one of the film gauges to maintain synchronism between the audio and video output signals.

Abstract: A pulse generator comprises a capacitor, means for periodically discharging the capacitor to generate pulses of electricity and means for recharging the capacitor between pulses. Means is included for sensing a residual reverse polarity charge on the capacitor after generation of a pulse and for using the energy stored in it to assist in recharging the capacitor for the next pulse.

Abstract: A thruster for use in a spacecraft uses vaporized propellant in its combustion chamber (110). Normally two propellants are used of the kind used for main thrusters so that two vaporization chambers are needed. Pressure valves (108, 109) are controlled by electronic means (220) to maintain current pressure.

Abstract: An impedance matching arrangement is suitable for use with a frequency hopping radio communications system which is operable over a wide frequency band, so as to match the operating impedance of the antenna at each of the frequencies used. As the frequency of the radio system hops from one frequency to another, a note of any impedance mismatch is noted and data derived therefrom is stored for future use when that frequency is next selected so as to reduce any impedance mismatch.

Abstract: A static-split tracking radar system with substantially improved performance. The system includes parallel signal processing channels for processing sum and difference signals from a target-seeking aerial array, to produce target tracking signals. Novel means are provided for trimming relative phase and gain of these channels to achieve substantially perfect matching, which gives a receiver stability sufficient for homing head use in a guided missile system. The system also includes a receiver for acquiring a reference frequency signal, the receiver having novel bandwidth adaptation and doppler tracking facilities. Other novel features provide improved clutter rejection and jamming immunity.

Abstract: A thruster system has a main bipropellant propulsion unit including a propulsion engine (50) and bipropellant supply having a tank (3) for an oxidizing agent and a tank (4) for a fuel. An auxiliary cold propellant thruster (21) uses propellant supplied by bleeding off vapor from the contents of the oxidizing agent tank (3).

Abstract: A novel multilayer photoconductive I.R. detector is formed by incorporating alternate p and n-type layers, such that many layers occupy the detector thickness. The detector may be considered as a n-type photoconductor containing buried isolated p-type regions which give rise to internal electric fields the effect of which is to enhance minority carrier lifetime and inhibit motion of minority carriers towards surfaces.

Abstract: An attitude control system for satellites includes a sensor (10) for generating output signals in response to variations in the attitude of the satellite. These signals are applied to a Kalman filter (12) which models the dynamic state of the satellite and instructs an attitude controller (13) to generate control signals for controlling the actuators. The system is responsive to the actual physical performance of the actuators to provide feed back to the modelling circuit.

Abstract: A microwave polarizer is provided in the form of a wedge at the termination of a rod of dielectric material. Preferably the wedge tapers exponentially in order to provide a good impedance match. Circularly polarized radiation propagating along the rod experiences a differential phase shift at the wedge. This phase shift may be arranged to be 90.degree., so that linearly polarized radiation exits from the wedge. A continuous circular or square guide is used to contain the dielectric rod so that simultaneous orthogonal signals can be converted to or from circular polarizations. Such a wedge termination may be provided at the end of a splashplate or polyrod antenna feed, for a satellite communication system, where right-handed circular polarization is used on the up-link and left-handed circular polarization is used on the down link.

Abstract: An impact fuze arrangement for a missile in which an electromagnetic field is set up within a compartment in the body of the missile and a warhead detonating signal is generated if the field intensity varies by more than a predetermined amount, as will happen due to distortion of the compartment on impact of the missile on a target. Fields may be set up within a plurality of compartments and warhead detonation may be made conditional on distortion of more than one of these compartments.

Abstract: Several cables extend between a buoyant body to be moored and the sinker on the sea bed. Intermediate spacing members hold the cables apart from one another to maintain the configuration. At zero rotation when the tether formation itself is in equilibrium half the number of cables exert a clockwise torque and half exert an equal and opposite anticlockwise torque. Any small rotation of the moored body causes the tension to increase in the cables opposing such rotation and to decrease in the other cables, so the body is restored to the equilibrium position. The tether thus exhibits high torsional stability. Cables can be configured to enable the tether to tilt relative to the buoyant body or sinker whilst still retaining high torsional stability.

Abstract: A telecine apparatus uses a line array electro-optical image transducer which is illuminated with bias light in addition to the projection light passing through the film. The bias light serves to operate the transducer on a linear portion of its characteristic, and the bias light is pulsed on during the integration periods of the transducer so as to give an accurate and reproducible control of the bias value. The transducer itself has a controllable variable integration period.

Abstract: A missile guidance system having means for deriving from a target angle tracking loop a signal indicative of an apparent movement of a target off a missile-to-target sight line caused by a change in missile attitude, and means for feeding said apparent movement signal into a space stabilization loop to adjust the position of the aerial to compensate for said apparent movement.

Abstract: A robust amplifier consists of two delay lines linked by a number of discrete amplifiers. Distortion correction is carried out by distortion feed forward. This is achieved by sampling the output of each amplifier at a coupler and then subtracting this sample from the input signal to later amplifiers along the delay line at directional coupler. As a result each discrete amplifier's distortion is corrected by all of the following discrete amplifiers in the amplifying circuit.

Abstract: In a phased array antenna the phase of the signal applied to each antenna element is controlled by a phase lock loop which is locked to the frequency of a reference oscillator but whose phase is offset from it alternatively by introducing a DC offset to an integrator within the phase lock loop or by presenting a digital code to a counter circuit.

Abstract: A safety device for use in the detonation of explosives, mines etc. Explosives are commonly detonated by a two stage operation, an explosive pellet is moved from a safe to an active position and then a hammer or electrical charge is fired to detonate the pellet. Failure of the second stage operation leaves the explosive in an unsafe condition, since the hammer or charge might fall as the fault is being investigated. The invention provides movement of the pellet from one safe position to another continuously and through an active position. If the hammer fails to fall as the pellet passes through the active position the device will assume a safe condition.

Abstract: The invention provides an infra-red target detection system in which an array of infra-red detectors is scanned vertically in swathes and horizontal scanning is effected by sampling the output of each detector in turn. Addresses of target detections in the vertical and horizontal are stored and read out into an X and Y co-ordinate target position store if a detection resulting from scanning in the vertical corresponds to a detection resulting from scanning in the horizontal.

Abstract: Conventionally, if several tasks have to be carried out simultaneously by receivers and transmitters, then a number of them are required, each having its own antenna.By employing the invention a single receiver or transmitter having one antenna can carry out a number of simultaneous tasks.A receiver has an array of antenna elements which receives signals and transmits them along conductors. Junctions include variable control means to apply a variable proportion of the signals on a conductor to one of a series of channels, each junction also giving a particular variable phase shift. By correctly selecting the amplitude and phase shift the outputs on the channels correspond to signals from respective directions of sensitivity of the receiver, and may be considered to represent a number of beams.

Abstract: The invention relates to a radar system of the type which can be presented with a number of tasks to be performed. Some of these tasks, e.g. the surveillance of areas at close range, may only require the transmission of low energy pulses and thus the full potential of the r.f. energy source has not previously been used while such tasks are being handled. By arranging for the tasks to be performed in a suitable overlapping sequence the full capability of the energy source is used at all times thereby increasing the throughput of tasks.

Abstract: A signal acquisition circuit for a missile guidance system has a phase lock loop which is responsive to incoming signals received from a target and will lock on to the frequency of the received signal. The bandwidth of the phase lock loop is altered in dependence on the signal being received in order to distinguish between a valid target and noise.