Abstract: A radio repeater (8) operates in a radio communication system (1) (such as a Bluetooth® communication system) including a mobile telephone (2) and a personal digital assistant (PDA) (3) each having a (Bluetooth®) transceiver (5,6). The repeater (8) is housed in a headset (7) incorporating an earpiece and microphone (not shown) for voice communication. The repeater (8) comprises a receive antenna (9) for receiving signals, e.g. in a band around 2.4 GHz; means (12) for shifting the frequency of the received signals by a constant frequency interval, e.g. to a band around 800 MHz; and a transmit antenna (14) for transmitting the frequency shifted signals. So, the mobile telephone (2) and the PDA (3) can communicate with each other directly using their Blue-tooth® transceivers (5,6), but, if there is no signal propagation path between them, such as when the body of a user (4) comes between them, they can receive the signals transmitted by the repeater (8).

Abstract: A method of operating a multimode transceiver comprises simultaneously transmitting (Tx) a signal having a relatively wide output frequency spectrum and receiving (Rx) a signal having a frequency spectrum narrower than that of the output frequency spectrum, but lying in the same band. A notch is introduced by a filter (18, 19, 20) into the output spectrum of the transmitted signal at a position corresponding to the received signal. The notch is adapted in response to at least one operating characteristic of the transceiver. The notch depth and bandwidth may be a function of the received and transmitted signal strengths, the relative frequency displacements of the received and transmitted signals and of the extent to which a degradation in the transmitted signal quality due to the notch can be tolerated.

Abstract: A method of protecting an apparatus from radio frequency interference, comprises a policing terminal (PT) detecting the presence of an interfering radio terminal (16) in the protected environment and actively rendering ineffective or terminating transmissions by the interfering radio terminal. Various options can be followed by the policing terminal (PT) including (a) attempting to become the master station of a network of which the interfering terminal is a member and instructing the members to close down or (b) failing to become the master station and transmitting interference signals for at least a selected portion, for example preamble and sync, of the duration of a data packet transmitted by the interfering station.

Abstract: A receiver having a variable threshold slicer stage, comprises a demodulator (14) for providing asynchronously samples of over-sampled raw demodulated data, a shift register (60) for delaying the over-sampled data by up to 2 bit periods. Samples in stages (62, 72) corresponding to substantially the mid-points in two successive bit periods are combined to form a signal (fXn) to be applied to a bit slicer (22). A bit stream signal from the bit slicer (22) is delayed by two concatenated shift registers (30,32) for 2 bit periods and is contemporaneously applied to a clock recovery circuit (74) for producing clock signals at the data rate for sampling the delayed sliced signal (Bn-2) at the center of bit to produce an output signal (34).

Abstract: An antenna diversity receiver has a low-IF receiving mode and a diversity selection mode, and a switch arrangement for coupling one of the antennas to the IF channels when in the receiving mode, and coupling each of the channels to a different one of the antennas in the selection mode. A diversity controller compares qualities of signals received simultaneously from the different antennas during the selection mode, and controls the switch arrangement in the receiving mode, to use the better antenna. The quality measurement is carried out during reception of a carrier before a preamble to a desired signal is received, so that there is more time to obtain a better signal quality measurement and to enable better averaging over time. The channels have a polyphase filter with switchable cross coupling between the channels, so that it acts as two independent low pass filters in the selection mode.

Abstract: There is disclosed method and apparatus for structured encoding of a previously encoded source (100, 105, 140) of data, where the structure (200, 210, 220, 230) is not defined in the received data. The invention finds particular application in block-based compression of digitised image or audio data derived from analogue sources, for example using MPEG encoding. The encoding introduces discontinuities in pixel colour and/or brightness across the block boundaries (200, 210, 220, 230), the introduction of which can lead to a marked deterioration in quality, and inefficient use of bandwidth. Encoding data using the same block and pixel structure used previously renders the discontinuities effectively invisible, substantially eliminating these problems.

Abstract: A footwear piece having a platform and a fluid assembly. The platform supports a wearer's foot and is engagable with an underlying surface. The platform has a rear heel region for engaging the wearer's heel and a sole region forwardly of the heel region for engaging a portion of the wearer's foot including the ball and toes of the wearer's foot. The fluid assembly has a first chamber containing a first quantity of a first fluid. The fluid assembly is provided on the platform and configured so that as the wearer of the footwear piece walks or runs, the wearer's heel is caused to apply a force to the first chamber that causes at least a portion of the first quantity of the first fluid to be discharged from the first chamber in such a manner that impact forces imparted from the platform to the wearer's heel are absorbed.

Abstract: A method of reducing seal stiction in a hydraulic cylinder is provided comprising the steps of providing a hydraulic cylinder, having a housing, a piston, and a seal, providing apparatus for rotating the seal about the piston, and rotating the seal about the axis of the piston at the same time as the piston begins to axially displace.

Abstract: A lift producing device is disclosed which is adapted to be connected to a vehicle to provide lift to the vehicle when the vehicle is moved relative to a first fluid medium having a first density and viscosity and being in contact with a second fluid medium adjacent the vehicle. The second fluid medium has a second fluid density which is different from the first fluid density. The lift producing device comprises opposed first and second major surfaces joined at a longitudinally extending leading edge and at a longitudinally extending trailing edge, with at least a portion of the longitudinally extending leading edge being spaced from the longitudinally extending trailing edge by a predetermined mean chord length.