The novel signalling post is adapted to be mounted on a flexible base member. The post comprises an outer, hollow, substantially rigid, transparent polycarbonate tubular member. The polycarbonate tubular member has a memory for returning to its original shape upon impact. An inner opaque flexible plastic tubular member is mounted inside the transparent tubular member and has a diameter to fittingly slide inside the transparent tubular member. The opaque tubular member has substantially no memory...

A signalling light according to the invention has a concave reflector with a substantially cylindrical lamp holder for an electric lamp. The position of the lamp holder can be adjusted from inside the reflector. The lamp holder is connected to the reflector so as to be rotatable about its axis. Means which can be manipulated from inside the reflector fix the lamp holder in any adjusted position. The construction of the signalling light makes it possible to position an asymmetric light source in ...

A compact thermal radiation signalling device employing infrared radiatio the device comprising a pattern of alternating high thermal emissivity zones with low emissivity zones, with a similarly patterned squirrel cage rotatable therearound to expose, to detecting means, at any given instant, emissivities of a predetermined wavelength. The heat causing the alternating emissivity zones to radiate is generated by a suitable chemical charge controllably ignitable within the device itself and carrie...

The method and apparatus of a signalling system wherein the message output signal is reconstituted from instances of recognition of preassigned groups of signal elements present in the transmission medium, are described. The transmission medium contains a plurality of messages each coded by groups composed of a plurality of discrete transmission signal elements, with the signal elements for different messages being of comparable energy intensity, with the transmission signal elements of the grou...

Visual display devices containing a matrix of areas which can be selectively illuminated to display a predetermined legend or symbol. In place of individual lamps used hitherto, the proposed visual display devices utilise bundles of optical fibres coupled to a reduced number of light sources, thus simplifying the assocated control circuitry.

Signalling apparatus in which a sensed change in condition, e.g. a window opened by an intruder or a valuable art object moved, causes the free end of a cantilevered spring to be snapped or twanged. A piezoelectric film bonded to the spring generates a pulsating voltage which energizes a transmitter, independently of any external power source. Remotely, a receiver which is selectively responsive to the transmitted pulsating signal generates an output signal indicating the change in condition, e....

There is disclosed herein a signalling system between two units for a data transmission system which transmits digital data messages character by character between these two units. The signalling system includes a transmitter-receiver disposed in each of the two units having a control output for controlling the data transfer registers of the corresponding one of the two units. These transmitters-receivers are connected by two wires. The first wire permits transmission of clock pulses for synchro...

A signal circuit for an oscilloscope includes iterative gain stages and signal-controlled attenuators which may be operated as gain verniers or as channel switches for multiplexed signal mixing. Bias currents in the active elements of gain stages near the output stage are shared with the active elements of preceding stages to reduce the total quiescent current requirement.

A small, portable lightweight, water-resistant, manually-operated signalling device. The signalling device includes a signalling assembly fully enclosed within a pair of hermetically sealed housings. The signalling assembly includes a signalling circuit and a pressure sensitive switch adapted, when depressed, to actuate the signalling circuit. One of the housings includes a recessed, flat, semi-rigid deflective wall having an indentation formed therein and in physical contact with the pressure s...

A signalling system designed to transmit and reliably detect alpha-numeric information with a single pulse indicating each different numeral from 0 to 9 and letters of the alphabet or code symbol. Each alpha-numeric symbol is coded in a single pulse of discreet difference lengths at the transmitting station. At the receiving station the train of pulses which is received is introduced into a transmission line having multiple taps with each tap related in position to detect a particular alpha-nume...