Abstract: In a mobile wireless communication system automatic speech recognition is performed in a distributed manner using a mobile station based near or front end stage which extracts and vector quantizes recognition feature parameters from frames of an utterance and an infrastructure based back or far end stage which reverses the vector quantization to recover the feature parameters and subjects the feature parameters to a Hidden Markov Model (HMM) evaluation to obtain a recognition decision for the utterance. In order to conserve network capacity, the size (Sz) of the codebook used for the vector quantization, and the corresponding number of bits (B) per codebook index B, are adapted on a dialogue-by dialogue basis in relation to the vocabulary size |V| for the dialogue. The adaptation is performed at the front end, accomplishes a tradeoff between expected recognition rate RR and expected bitrate BR by optimizing a metric which is a function of both.

Abstract: A communication station and communication method for effectively multiplexing data into a combined data stream by adding a special header to the combined data packet. The bit positions of this special header indicate the presence of data packets in a data stream in a combined data packer. The combined data packet is transmitted from the first to the second communication station through a first communication channel. Changes in the data streams can be communicated to the receiving communication station through a second communication channel, so that the second communication station can restore relations between data streams and recreate stripped headers.

Abstract: The error concealment method improves the signal quality in transmission systems. The method is used for processing speech signals which have been encoded to speech parameters before transmission via a transmission channel. It allows detection at the receiving end of corrupted signal parameters due to adverse channel conditions. The method comprises estimations of the signal quality and a statistic study of the evolution of the signal parameters so as to derive an indication that the parameter is probably corrupted. A first signal quality estimation is performed. It may be e.g. an estimation of the error probability within the most important bits of the frame. A second signal quality estimation is performed. It may be e.g. an estimation of the error probability within all bits of the frame. Depending on the results of the estimations, the statistic study is performed in order to detect which signal parameters are probably corrupted.

Abstract: A radio communication system has a random access channel for the transmission of data (214) from a secondary station to a primary station. Such a channel is intended for use by secondary stations having data (214) to transmit to a primary station while not actually engaged in a call. A problem with known systems of this type is that a secondary station requesting access also specifies which of a plurality of resources it wishes to access. If that resource is busy access is denied, even if other suitable channels are available. In the present system allocation of a channel is performed by the primary station when acknowledging (206,210) a secondary station's access attempt (202,208), thereby eliminating wasted attempts. In one embodiment the primary station also periodically broadcasts a short message indicating the availability of channels for access attempts.

Abstract: A frequency hopping system comprises a transmitting station and a receiving station, both stations storing a frequency hopping sequence comprising a predetermined sequence of N frequencies, where N is an integer greater than 2. In order for the receiving station to acquire synchronization with the transmitter which is continuously hopping through the sequence of frequencies, the receiver initiates a search by tuning to one of the N frequencies and checking if that frequency corresponds to the currently transmitted frequency during that hop period. If it does not correspond, the receiver eliminates the phase of hopping sequence associated with that frequency and tunes to another of the N frequencies with the exception of the next frequency in the eliminated phase and checks for correspondence. If there is not correspondence then the phase of the hopping sequence associated with that frequency is also eliminated from the search.

Abstract: The present invention relates to a data processing system comprising a processor (100), at least one data memory (132), at least one program memory (134) and a main bus (110), common to the data and program memories and connecting these memories to the processor, characterized in that at least one of the memories has a rapid-access mode and in that the device also comprises a distribution interface (120) between the main bus (110) and the memories in order to alternately put in communication, by means of the main bus, one from among the data memory and the program memory with the processor, in a so-called active-access mode, and to keep the other memory in a so-called passive-access mode allowing subsequent rapid access.

Abstract: A personal communications apparatus comprises a first part, having a microphone (114), and a second part, having a loudspeaker (118). The first part is adapted to be worn on a user's wrist (202) and the second part is adapted to be worn on their finger. In use, the user's hand is held up to the side of their head, thereby placing the microphone (114) adjacent to their mouth and the loudspeaker (118) adjacent to their ear. Communication between first and second parts of the apparatus is by means of signals transmitted via the user's skin. In a non-illustrated embodiment the second part is adapted to be worn on the ear.

Abstract: The present invention describes a communication system comprising a primary radio station (PS) and at least one secondary radio station (SS), intended to be in motion (MOT). The secondary radio station has at least one controllable structure (CS) for communicating with the primary radio station, and control means (CONT) for controlling the controllable structure depending on the movements of the secondary radio station. The control means of the controllable structure comprise magnetic field sensors (MFS) and gravitational field sensors (GFS) for providing measurements of the earth magnetic (H) and gravitational (G) fields, and computing means (COMP) for computing control information from these measurements. The computing means read the outputs of each sensor and make the calculations required to control the controllable structure at appropriate time intervals depending on the motion state of the secondary radio station.

Abstract: A mobile radiotelephony device intended for accommodating a linked user identification module offers protection against theft. The device prevents a normal operation of the device with an unlinked identification module, and permits the normal operation of the device with the linked identification module until such time the device has been inactive for a defined period of time. A debugging code can be supplied to the device subsequent to a detection of the defined period of time to again permit the normal operation of the device with linked identification module.

Abstract: A portable terminal of a cellular communication system is provided with apparatus for initiating a handover procedure to handover a connection established with one radio termination of a fixed system to another radio termination of the fixed system. The apparatus continually monitors system communication channels for transmissions by the radio terminations received at the portable terminal and identifies the nearest radio termination to be the one from which signals are received with the highest radio signal strength. If a connection is initially established by the mobile terminal with a first radio termination, but the mobile terminal subsequently moves away from that radio termination, the apparatus initiates a handover attempt of the connection to the radio termination from which transmissions are now received with the highest radio signal strength. Normally signals received with the highest signal strength will originate from the closest fixed radio termination.

Abstract: A method of conformance testing of a secondary station for use in a radio communication system which permits a soft handover process in which the secondary station engages in communication with a plurality of primary stations. The method permits testing the response of the secondary station to power control commands received simultaneously from each of the plurality of primary stations instructing it to adjust its output transmission power. In particular, the method enables testing the secondary station's assessment of the reliability of the power control commands received from each primary station, which has not been possible previously. The test is performed by transmitting known sequences of power control commands to the secondary station from each of the primary stations, then comparing the actual pattern of changes in output transmission power with the expected pattern of changes.

Abstract: Switching power amplifiers are used for example in audio applications. Using Class D technology is used to obtain efficient performance. To improve the switching power amplifier further it is proposed to combine a plurality of low-power switching power stages into a larger amplifier. The precision and efficiency of a switching power amplifier is improved without deteriorating the noise and EMI.

Abstract: This apparatus comprises a battery (15) for supplying a voltage to the apparatus, a power cut detecting circuit (20) for detecting cuts of this supply voltage, a random-access memory (12) fed by this battery (15). A processor (10) loads this data memory. To avoid this memory being reloaded after a very brief electric power cut of the battery, its integrity is tested. If its contents have remained intact, there is no need for it to be reloaded.

Abstract: A radio communication system has a random access channel for the transmission of data (214) from a secondary station to a primary station. Such a channel is intended for use by secondary stations having data (214) to transmit to a primary station while not actually engaged in a call. By enabling access requests (202) to be transmitted with a greater range of possible signatures, a much greater number of degrees of freedom is available to a secondary station requesting access to a random access channel. This enables significantly improved efficiency of resource allocation by increasing the amount of information transmitted to the primary station by the access request (202).

Abstract: A protective casing (12) for an electronic appliance (10) is of the type which has a shell (18) in which there is produced an opening (20) closed off by a body (22) made from transparent material with a general flat shape, of the type in which at least one internal peripheral annular fixing area (30) of the transparent body (22) is fixed to a facing area (32) of the periphery of the opening (20) with the interposing of a first decorative cladding (38) between the peripheral fixing area (30) of the transparent body (22), where the peripheral fixing area (30) is inclined with respect to the overall plane of the transparent body (22).

Abstract: The contrast between solder balls and substrate of a Ball Grid Array (BGA) as visualized by a camera of a computer vision system is improved sufficiently to enable reliable recognition in the poor contrast situation when the balls are silver colored and the substrate background is white or light colored by illuminating the BGA with polarized light, and the camera viewing the light reflected from the BGA via a polarization filter oriented to not pass light reflected from the solder balls but to pass light reflected from the substrate.

Abstract: A portable apparatus including an acoustic signal generation device mainly comprises an input unit (IU) adapted to supply a digital input signal (in). The apparatus further comprises a delay line (DL) adapted to receive N samples of the digital input signal, to store and delay data values associated with the samples. The apparatus also comprises an arithmetic unit (AU) adapted to combine at least two delayed data values received from the delay line in order to them a modified data value, which is again loaded into the delay line and delayed by the value N, the modified data values together also forming an output signal (s), whose frequency content includes the fundamental frequency of the signal to be produced, enriched with harmonics of different intensities. The portable apparatus finally comprises an output unit (OU) adapted to produce a musical sound on the basis of said output signal.

Abstract: An antenna arrangement comprises a patch conductor (102) supported substantially parallel to a ground plane (104). The patch conductor includes first (106) and second (108) connection points, for connection to radio circuitry, and further incorporates a slot (202) between the first and second points. The antenna can be operated in a plurality of modes by variations in the impedances connected to the first and second points. For example, if signals are fed to the first point (106) then a high frequency antenna is obtained by connecting the second point (108) to ground and a low frequency antenna by leaving the second point (108) open circuit. A wide range of embodiments having alternative connection arrangements are possible.

Abstract: A radio communication system has means for improving power control of a communication channel for the transmission of data after an interruption in the transmission. This is done by adjusting the transmission power immediately after the interruption by an offset from the power used before the interruption. The offset may be fixed or may be determined from the transmission power in the period before the interruption. This technique reduces, on average, the time taken for power control to be re-established, thereby addressing the problem that data transmissions immediately after the interruption are likely to be corrupted if the power level is too low, or to generate extra interference if the power level is too high.

Abstract: A receiver (REC) is tunable (TUN) to any one of a plurality of channels (CH) by means of channel-select commands (CSC). The receiver tunes to (SRCH) a channel (CH[i]) with a signal (S) having a channel identification (CHIND) that identifies the channel (CH[i]). The receiver defines (DEF) a tuning reference (REF) on the basis of the channel identification (CHIND) and the channel-select command (CSC[j]), which is used for tuning to such a channel (CH[i]). This allows a reduction of cost, because the receiver need not rely on accuracy of tuning components in order to be certain which channel-select command has to be applied for tuning to a particular channel.