Abstract: Selectable signal connection provisions are made for passing signals relative to logic circuitry of digital bipolar semiconductor integrated circuits. Each such provision has formed on the chip for each selectable signal connection, an active circuit element whose conduction state relative to signals concerned is controlled by applied circuit conditions. The conditions are selected by operative control circuitry responsive to a configuring or selection signal applied temporarily thereto for switching between stable states and thus determining the conduction state of the active circuit element.

Abstract: A communications scrambler operates on a digital basis in which digital or digitized incoming and outgoing signals are merged (60) into a single bit stream for application to a binary bit store (12) and retrieval therefrom for separation (62) of those signals. Multi-bit segments of each signal represent unintelligibly fragments of those signals and are stored and read-out under control of store addressing counters (36, 38, 76) whose outputs are selectively modified (48, 50) to achieve time-dispersion encryption/decryption for outgoing/incoming signals in multi-plexed writing and reading of the store (12). Digitization (52, 54) and reconstitution (64, 66) of analogue incoming and outgoing signals is provided using inherently digital on-chip circuitry and one-bit per sample at a high rate for easy interfacing in telephone/radio systems. The whole control system can be put onto a simple semiconductor chip of ULA type.

Abstract: In an overhead electric and optical transmission system in which at least one of the overhead electric conductors incorporates an optical guide, the overhead electric conductor is mechanically secured to a tower or other rigid support structure by a mechanical connection in which an end of the overhead electric conductor is mechanically secured to and is electrically insulated from the tower or other rigid support structure by an elongate tension insulator having at least one throughbore, the optical guide of the conductor passes from the conductor through the throughbore of the tension insulator to an optical guide joint remote from the insulator, and the electric conductor is electrically connected to another electric conductor.

Abstract: A lift-producing arrangement suitable for driving a boat by the Magnus effect comprises an elongate tubular envelope mounted for rotation about its longitudinal axis. A drive is provided to rotate the envelope. The envelope is of flexible material, e.g., canvas, to achieve improved performance. Preferably, the envelope is held erect by inflation. The arrangement may be used in addition to a conventional screw-propulsion system for increased fuel economy.