Abstract: A radio communication system has a random access channel for the transmission of data from a secondary station to a primary station while the secondary station is not engaged in a call. A secondary station wishing to use a random access channel resource transmits a preamble encoded with a signature corresponding to the required resource. In response the primary station can transmit a positive acknowledgement (ACK) corresponding to the received preamble, indicating that a channel is available, or a negative acknowledgement (NACK), indicating that the resource is not available. A first set of signatures are used to encode ACKs and a second set of signatures are used to encode NACKs. The two sets of signatures have the property that no signature in one set is the inverse of a signature in the other set, thereby avoiding the possibility of simultaneously transmitting an ACK and a NACK with signatures that are the inverse of one another.

Abstract: The invention relates to a switching arrangement for operating at least one LED, which switching arrangement is provided with input terminals (1, 2) for connecting a supply source, —output terminals (3, 4) for connecting the LED to be operated, —a first series circuit (I) between one of the input terminals (1) and one of the output terminals (3), including at least a self-inductance (L), a capacitor (C) and a diode (D), —a second series circuit (II) between the input terminals, including at least the self-inductance (L) and a switching element (S) which is alternately switched to a conducting state and a non-conducting state at a high frequency, —a third series circuit (III) between the output terminals, including the diode and an inductive winding (SW). According to the invention, the inductive winding forms a first winding (SW1) of a transformer (T) which has a second winding (SW2) that forms part of the first series circuit and which also has a connection point with the first winding.

Abstract: The present invention relates to an Electronic ballast for operating a high-pressure discharge lamp, comprising a switched-mode power supply circuit (SMPS) for supplying a rail voltage Vrail to the high pressure discharge lamp, the power supply circuit comprising a half bridge commutating forward circuit including an inductance (Lhbcf), a capacitor circuit of a first capacitor (Cs1) and a second capacitor (Cs2) in series, the lamp (LA) being connectable between the inductance (Lhbcf) and a midpoint (M) between the first and second capacitor (Cs1,Cs2); a duty cycle control circuit, connected to the switched-mode power supply circuit, for controlling the duty cycle of the half bridge commutating forward circuit; and overvoltage protection means for protecting said capacitors against overvoltage, comprising—a midpoint voltage detection circuit for detecting the voltage at the midpoint between the first and second capacitor, the midpoint voltage detection circuit providing a first signal representative of the det

Abstract: The present invention relates to a device for operating a high-pressure discharge lamp, comprising a switched mode power supply circuit (SMPS) for supplying power to the high pressure discharge lamp from a supply voltage, the power supply circuit comprising a half bridge commutating forward (HBCF) circuit including an inductance(Lhbcf?), a capacitor circuit of a first capacitor (Cs1) and a second capacitor (Cs2) in series, the lamp (LA) being connectable between the inductance (Lhbcf) and a point (M) between the first and second capacitor (Cs1,Cs2); wherein overvoltage protection means are connected parallel to the lamp, which switch from an off-state with a high resistance operation to an on-state with a low resistance operation when the voltage difference across the protection means exceeds a breakover voltage (Vbo), the breakover voltage (Vbo) being selected to correspond to a predetermined maximum voltage across the first or the second capacitor (Cs1,Cs2).

Abstract: Apparatus for identifying the four coordinates of a window on a visual display monitor, include a device for obtaining digital data corresponding to pixels of an image to be displayed on the monitor, a memory arranged to receive the digital data, a comparator arranged to compare the values of data for horizontally and vertically adjacent pixels, a generator for generating a gradient value indicative of the difference in luminance of adjacent pixels—in the horizontal and in the vertical directions, a memory for storing the gradient values, a detector for detecting a unique configuration in the gradient values to identify the three coordinates of one edge of the window, and a device for checking in the direction perpendicular to the identified edge for a corresponding unique configuration, to determine the fourth coordinate of the window.

Abstract: A radio communication system includes a primary station which is arranged to transmit a series of data packets to a secondary station which operates according to an ARQ scheme for acknowledging correct reception of each packet. The primary station transmits error correction information relating to any packets that are not received correctly, thereby enabling the secondary station to extract correctly the data. The data packets are transmitted via a plurality of logical channels, so that an error in transmission of one packet does not hold up transmission of packets in other channels. Transfer of data transmission from one primary station to another is done by transferring each channel when correct reception of a data packet on that channel has been acknowledged, thereby avoiding the extra signaling required in transferring logical channels in which a data packet has been received in error and the error correction transmissions have not been completed.

Abstract: A personal communications apparatus comprises an elongate body 202 incorporating an antenna diversity arrangement in which first and second antennas (102A, 102B) are located at opposite ends of the body. In one embodiment a microphone (114) is located at the tip of one antenna (102A) and a loudspeaker (116) at the tip of the other antenna (102B). The microphone (114) and loudspeaker (116) act as top loads to their respective antennas, thereby enabling the use of shorter antennas. The antennas (102A, 102B) may be formed from coaxial cable, enabling them to provide electrical connections between the microphone (114) or loudspeaker (116) and transceiver circuitry in the body of the apparatus. By arranging for the microphone (114) and loudspeaker (116) to have low impedances at radio frequencies, the coaxial cable acts as an inductive stub and enables the antennas (102A, 102B) to be further shortened.

Abstract: A method and apparatus for transferring information over a communications link includes transmitting information at a first power level, monitoring for correct reception of the transmitted information and transmitting further information at a second-, greater power level than that used for the original transmission if correct reception did not occur. The further information allows the content of the originally transmitted information to be established and in one embodiment constitutes a retransmission of the originally transmitted information. By retransmitting at a greater power level the probability of correct reception is enhanced, especially when the communications link is wireless. A transmitter employing the present invention may offer reduced power consumption since the transmission power level used for the original transmission may be lower than that used by a transmitter not benefiting from the present invention.

Abstract: The user is enabled to upload, to a server on the Internet, information from a first contact data base in a first communications apparatus. The server manipulates the uploaded information and extracts or converts the format of the records for a second contact data base of a second communications apparatus.

Abstract: A method of and arrangement for providing access to a consumer device (101). A user can switch between multiple content providers. To switch, he calls up a set of representations (202-207) of offerings by content providers (107, 108, 109). He can then select a content provider. The selection is submitted to a gateway system (106), which then provides the selected content provider access to the consumer device (101), preferably in return for a fee paid by the selected content provider. The invention makes it easier for users to switch content providers even when descrambling boxes, subscriptions and other hassles are normally involved in switching. All these hassles are taken care of by the gateway (106).

Abstract: A communication system includes first and second beacon devices capable of wireless message transmission and at least one portable client device capable of receiving such message transmissions. The client device is arranged to broadcast an inquiry message according to a first communication protocol, such as Bluetooth. The first beacon detects such inquiry messages and replies with an inquiry response containing an identifier for the second beacon, enabling the second beacon and client device to perform a service interaction. In an alternative embodiment receipt of the inquiry message is notified to the second beacon which then sends the inquiry response to the client device.

Abstract: A method of operating a radio communication system in which secondary stations use dedicated time slots to request services from a primary station. A secondary station wishing to request a service sends a request in every time slot allocated to it until it receives an acknowledgement from the primary station. The primary station can use combining techniques on multiple time slots to identify the presence or absence of a request from a secondary station with improved accuracy.

Abstract: A method of reconfiguring the software interface in software defined radios in which when a transmitting station (PS) sends a reconfiguration software message to a receiving station (SS), the receiving station responds with a message giving an estimated time duration for carrying-out the reconfiguration of its software. The transmitting station listens for the estimated time duration for a message which confirms that the receiving station has been successfully reconfigured and commences normal communications using the new configuration. The estimated time duration may be computed using indicia present in the reconfiguration software message.

Abstract: The invention relates to a low-pressure gas discharge lamp which includes at least one discharge vessel and at least two capacitive coupling-in structures and operates at an operating frequency f. In order to achieve a better efficiency in combination with a small structural volume, a high luminous flux, a low operating voltage, a low electromagnetic emission, a high resistance against switching transients and a long service life for the low-pressure gas discharge lamp, it is proposed to form each capacitive coupling-in structure from at least one dielectric having a thickness d and a dielectric constant ?, each dielectric being subject to the condition d/(f.?)<10?8 cm.s. A substantially larger amount of light can thus be generated per lamp length (lumen/cm).

Abstract: A radio communication system has improved power control of transmissions between a first station and a second station. The second station adjusts the power of its transmissions to the first station in response to power control commands received from the first station. The first station determines when it has synchronised to transmissions from the second station and informs the second station of synchronisation. After synchronisation has been signalled, the rate of adjustment of transmission power by the second station is increased (508). The changed rate of power control can be achieved by adjustments to the power control step size, or by other modifications to the response of the second station to received power control commands or to its rate of reception of power control commands. These techniques overcome the problem that, because synchronisation can take a significant time to be established, there is a danger that transmission power may be increased too much and cause unacceptable interference.

Abstract: A portable communication device has an antenna configuration that allows to form various different antenna directivity configurations. In particular, a control device discriminates between a transmitting state and a receiving state of the communication device. As based thereon, it effects various non-uniform selection patterns among the directivity configurations.

Abstract: A communication system is disclosed having a wireless telephone and a base station. The wireless telephone has a transceiver, a microphone, a speaker and a keyboard. The base station is connectable to the wireless telephone by a radio link and is connected to a switched network. The keyboard of the wireless telephone includes an emergency key which dials a pre-stored number and activates the microphone and speaker for hands-free operation of the wireless telephone.

Abstract: A method of transferring information in units over a wireless digital communications link between a transmitting station and a receiving station comprising the steps of: transmitting first information units at a first energy level; monitoring if correct reception of the transmitted units occurred; and transmitting second information units associated with the first information units, for which first information units the monitoring did not indicate correct reception occurred, at second energy levels, the second information units allowing the content of the first information units to be established, wherein at least one of the associated second information units is transmitted at an energy level which is selected at least partly so as to minimise the total transmitted energy when averaged over a series of first information unit transmissions with respective second information unit transmissions.

Abstract: A high-pressure discharge lamp of the ceramic metal halide type having power ranges of about 150 W to about 1000 W. Such lamps have outer bulb enclosing a cylindrical ceramic discharge vessel enclosing a discharge space. The discharge vessel includes an ionizable material containing a metal halide; a first and second discharge electrode feedthrough; and a first and second current conductor connected to the first and second discharge electrode feedthrough, respectively. A frame wire structure includes at least one frame wire, connected to the current conductors, through a conductor. The frame wire structure extends between the ceramic discharge vessel and the glass bulb, and is effective to reduce arc bending, regardless of the orientation of the lamp during operation in a fixture and regardless of the relative position of the frame wire to the arc tube.

Abstract: A method for generating and coding animated graphic images for transmission to hand-held or mobile devices uses an object-component technique wherein images are composed from a limited set of component types, particularly points and polygons. An initial frame is defined as a list of objects to be displayed. Subsequent frames are encoded as a list of changes to the objects to the previous frame.