摘要:
A digital phase shift arrangement comprising a frequency multiplier (10) to which an input signal can be applied, frequency division means to which the output of the multiplier is applied, the frequency division means (11,12) being arranged to produce a plurality of outputs of identical frequency each delayed by a different amount with respect to the input frequency and means (13,14) for selecting one of the outputs of the frequency division means.
摘要:
A passive distribution system for electromagnetic radiation using waveguides (10) and couplers (20) wherein radiation from a source (11) is distributed to a number of destination points (12, 13), including means at destination points for determining the power levels received at the destination points and means for transmitting from the destination points to the source location information representing said received power levels.
摘要:
A cross connect core switch comprises two or more sub-assemblies (41, 42) each of which includes a plurality of core cards associated with a back plane having a respective multiline bus (31, 32). Means (38, 39, 43) are provided on each core card of a sub-assembly so that each core card can assemble outputs from the bus lines of both or all sub-assemblies rather than just the bus lines on its own back plane.
摘要:
An optical fibre gland for a submerged repeater comprising an insulating body (1) having a bore (4) accommodating a pressure tube (5). A high pressure end fitting (8) is secured to the tube and the body and a low pressure end fitting (12) is secured only to the tube. The tube and fibres are water and gas blocked and the construction is such as to enable the gland to operate satisfactorily over a wide temperature range.
摘要:
A circularly polarised antenna including first and second multiple patch antenna structures dimensioned to operate at two distinct frequencies, each antenna structure consisting of four shorted patches, the patches (11a) of the first structure being spaced from a ground plane (10) by dielectric material (12), the patches (14a) of the second structure being spaced from the patches of the first structure by dielectric material (13), the patches of the second structure each overlying a corresponding patch of the first structure and each having a dimension λ m (2) /4 which is less than the dimension λ m (1) /4 of the corresponding patch of the first structure, with feed means (16a, 17a) for each of the patches, the patches of both structures being disposed in the planes of the patches so that the radiating edges of the two patch structures form superimposed antenna structures.
摘要:
The invention provides a communications system comprising a plurality of functional units including a switching network and peripheral units, and a message switch comprising a processor and data port circuits for interfacing with respective ones of the functional units. The message switch is adapted for interconnecting any one of the functional units with any other of the functional units. The data port circuits are connected to a transaction bus internal to the message switch and are respectively addressable by a physical address contained in the header of each message to be routed. The routing header of each message comprises a physical address and a logical address. The message switch also comprises a mapper circuit addressable by a predetermined physical address for translating the logical address to a physical address and for replacing the predetermined physical address with the translated physical address while the message data is retained in a source port message buffer.
摘要:
The invention provides a communications system comprising a plurality of functional units including a switching network and peripheral units, and a message switch comprising a processor and data port circuits for interfacing with respective ones of the functional units. The message switch is adapted for interconnecting any one of the functional units with any other of the functional units. The data port circuits are connected to a transaction bus internal to the message switch and are respectively addressable by a physical address contained in the header of each message to be routed. The routing header of each message comprises a physical address and a logical address. The message switch also comprises a mapper circuit addressable by a predetermined physical address for translating the logical address to a physical address and for replacing the predetermined physical address with the translated physical address while the message data is retained in a source port message buffer.