Abstract: Disclosed is a combined antenna and helicopter rotor blade. The antenna has one or more electrically non-conductive rotor blades, each having an electrical conductor positioned parallel to the major axis of a respective rotor blade. An electrical connection is provided to connect the antenna to a radio for the reception or transmission of radio waves. Also disclosed is a communications system including apparatus for the transmission or reception of radio waves. Two of the electrical conductors, having angular positions nearer to a predetermined angular position are connected via the electrical connector to the radio. The remaining conductors may either be connected to the body of the helicopter or supplied with a signal out of phase compared to that supplied to the two electrical conductors.

Abstract: An elapsed time recording device includes a counter (130) for incrementally advancing a count value from an initial value towards and beyond a threshold in response to successive clock pulses of a clock signal. Control logic (140) enables the counter (130) to incrementally advance the count value in response to a first input (pin 3) and a second input (pin 1) being at or near a first voltage level, and holds the count value in response to the first input (pin 3) being at or near a second voltage level and the second input (pin 1) being at or near the first voltage level. Setting logic (210) sets the count value to a value beyond the threshold in response to the first input (pin 3) and the second input (pin 1) being at or near the second voltage level when the count value is between the initial value and the threshold.

Abstract: A nonlinear inductor for a CRT line timebase circuit comprises a bobbin carrying an inductive coil 41 and a first permanent magnet adjacent the coil. A second permanent magnet is positioned and oriented relative to the first magnet in such a manner that the magnetic field generated by the nonlinear inductor is substantially reduced. Because the second magnet is integral, the nonlinear inductor occupies the same printed circuit board area as a conventional nonlinear inductor. Furthermore, because the second magnet is oriented to substantially cancel the magnetic field, no additional magnets are required for deflecting the magnet field away from the CRT.

Abstract: Solid state optoelectronic control apparatus responsive to manual stimulus is presented. The control apparatus comprises: a transmitter (20) having a light source (38) for projecting a beam of light along a path normally directed away from a photo sensitive detector (24); characterised in that the control apparatus further comprises: a receiver (21) for generating an enable pulse having a duration determined by a length of time for which the beam is reflected towards the detector by a digit or similarly reflective article; and conversion means (31) for varying an output signal level (44) as a function of the duration of the enable pulse. The conversion means increases the signal level (44) in response to and during a first enable pulse, and decreases the signal level in response to and during a second enable pulse occurring next to the first enable pulse.

Abstract: Linearity correction apparatus for a raster scanned cathode ray tube display device is presented. The apparatus comprises first means (16) for generating a correction signal to correct an asymmetric non linearity in a sawtooth electron beam line deflection current. The line deflection current is generated by a line timebase circuit for energising electromagnetic electron beam deflection coils of the cathode ray tube. The apparatus further comprises second means (70,90,91) cooperative with the first means (16) and responsive to a change in line timebase frequency for compensating a variation in the correction signal generated by the first means (16) in response to said change in line timebase frequency.