Abstract: A radio receiver (100) comprises an analogue to digital converter (30) for generating a data word representative of a received radio signal and a gain control stage (40) comprising a first register (42) for storing the data word. The gain control stage (40) is adapted to control the numerical value of the data word by controlling the position of the data word in the first register (42).

Abstract: An arrangement (30) and a method for digitally filtering a time-discrete digital signal, wherein the signal is transformed to the frequency domain using discrete Fourier transformation (31), the signal is filtered in the frequency domain (33), wherein a filter response can be adapted in real time as required to respond to changes in the interference environment, and the filtered signal is transformed back to the time domain using inverse discrete Fourier transformation (32) to create an output signal, and wherein bin frequencies of said signal in the frequency domain are translated by a real amount and the sampling rate of the output signal is changed by a real factor.

Abstract: A receiver comprises an adaptive filter having an input for a digitized input signal, means for storing a pre-designed filter characteristic, means for analyzing a digital. representation of the input signal to determine a desired position of the filter characteristic to match the system requirements, and means for adapting the stored pre-designed filter characteristic in the frequency domain and/or the time domain to match the system requirements and for transforming the adapted filter characteristic to the time domain to update coefficients for the adaptive filter and for loading updated coefficients into adaptive filter. The updating of the coefficients may be done periodically. The adaptation may be one or more of adjusting bandwidth, frequency shift and, in the case of a bandpass characteristic, superimposing characteristics.

Abstract: A device processes signals from a plurality of signal channels that are received in parallel. A channel processing circuit (12a,b, 14a,b), applies a series of filtering operations selectively to the signal from a first one of the signal channels. A filter management circuit (18) detects a reception condition from reception of a signal in a second one of the signal channels. The filter management circuit (18) controls application of at least a part of said filtering operations to the signal from the first one the signal channels by the channel processing circuit (12a,b, 14a,b), dependent on the detected reception condition. Selected filter operations may be enabled or disabled. Thus, power consumption may be reduced. In an embodiment, the detected reception condition is determined as a by-product of functional reception of another channel. Thus power consumption for the detection of the reception condition is also reduced.

Abstract: A receiver comprises an adaptive filter having an input for a digitized input signal, means for storing a pre-designed filter characteristic, means for analyzing a digital. representation of the input signal to determine a desired position of the filter characteristic to match the system requirements, and means for adapting the stored pre-designed filter characteristic in the frequency domain and/or the time domain to match the system requirements and for transforming the adapted filter characteristic to the time domain to update coefficients for the adaptive filter and for loading updated coefficients into adaptive filter. The updating of the coefficients may be done periodically. The adaptation may be one or more of adjusting bandwidth, frequency shift and, in the case of a bandpass characteristic, superimposing characteristics.

Abstract: A receiver comprises an adaptive filter having an input for a digitized input signal, means for storing a pre-designed filter characteristic, means for analyzing a digital representation of the input signal to determine a desired position of the filter characteristic to match the system requirements, and means for adapting the stored pre-designed filter characteristic in the frequency domain and/or the time domain to match the system requirements and for transforming the adapted filter characteristic to the time domain to update coefficients for the adaptive filter and for loading updated coefficients into adaptive filter. The updating of the coefficients may be done periodically. The adaptation may be one or more of adjusting bandwidth, frequency shift and, in the case of a bandpass characteristic, superimposing characteristics.

Abstract: An arrangement (30) and a method for digitally filtering a time-discrete digital signal, wherein the signal is transformed to the frequency domain using discrete Fourier transformation (31), the signal is filtered in the frequency domain (33), wherein a filter response can be adapted in real time as required to respond to changes in the interference environment, and the filtered signal is transformed back to the time domain using inverse discrete Fourier transformation (32) to create an output signal, and wherein bin frequencies of said signal in the frequency domain are translated by a real amount and the sampling rate of the output signal is changed by a real factor.

Abstract: A radio receiver (100) comprises an analogue to digital converter (30) for generating a data word representative of received radio signal and a gain control stage (40) comprising a first register (42) for storing the data word. The gain control stage (40) is adapted to control the numerical value of the data word by controlling the position of the data word in the first register (42).

Abstract: A device processes signals from a plurality of signal channels that are received in parallel. A channel processing circuit (12a,b, 14a,b), applies a series of filtering operations selectively to the signal from a first one of the signal channels. A filter management circuit (18) detects a reception condition from reception of a signal in a second one of the signal channels. The filter management circuit (18) controls application of at least a part of said filtering operations to the signal from the first one the signal channels by the channel processing circuit (12a,b, 14a,b), dependent on the detected reception condition. Selected filter operations may be enabled or disabled. Thus, power consumption may be reduced. In an embodiment, the detected reception condition is determined as a by-product of functional reception of another channel. Thus power consumption for the detection of the reception condition is also reduced.

Abstract: A receiver uses a sigma delta ADC (126) and an adaptable digital filter (132). Detector circuitry detects information about unwanted parts of the signal from an oversampled digital signal, before the filtering, and feeds forward the detected information to the filter, to adapt the filter. By feeding forward the detection information, rather than feeding back an output of the filter, the adaptation can respond much more quickly to rapid changes in the unwanted interference. This enables reduced filtering to save power when interference is low, without risking a sudden increase in interference causing an avalanche of errors before the filter can be adapted correctly. The filter receives the oversampled digital signal combines decimation and channel filtering in one stage.

Abstract: A radio receiver (600) in which a local oscillator frequency is selected dependent on the level of a received signal. The received signal may be a wanted signal or an interferer, or the level of both may be measured.

Abstract: A FIR filter (20) has a delay line comprising four delay elements (21a, 21b, 21c, 21d) for delaying a signal received at a filter input (22) and four multipliers (24a, 24b, 24c, 24d) for multiplying the delayed signals by respective partial filter coefficients a, b, c, d. The delay elements (21a, 21b, 21c, 21d) and multipliers (24a, 24b, 24c, 24d) are connected alternately in series. Four taps (23a, 23b, 23c, 23d) extract the signal from the delay line immediately after each of the delay elements (21a, 21b, 21c, 21d) and output the delayed, multiplied signals to an adder (25) for adding the delayed, multiplied signals to generate a filter output (26). The partial filter coefficients a, b, c, d effectively combine to implement filter coefficients A, B, C, D for the taps (23a, 23b, 23c, 23d), e.g. with A=a, B=a*b, C=a*b*c and D=a*b*c*d.

Abstract: A receiver uses a sigma delta ADC (126) and an adaptable digital filter (132). Detector circuitry detects information about unwanted parts of the signal from an oversampled digital signal, before the filtering, and feeds forward the detected information to the filter, to adapt the filter. By feeding forward the detection information, rather than feeding back an output of the filter, the adaptation can respond much more quickly to rapid changes in the unwanted interference. This enables reduced filtering to save power when interference is low, without risking a sudden increase in interference causing an avalanche of errors before the filter can be adapted correctly. The filter receives the oversampled digital signal combines decimation and channel filtering in one stage.

Abstract: A method of, and receiver for, cancelling an unwanted first signal having a bandwidth at least a part of which overlies the bandwidth of a wanted second signal, the bandwidth of one of the first and second signals being greater than that of the other The method comprises receiving the first and second signals (10, 12) and respectively frequency down converting (18,22,26 and 20,24,28) the first and second signals to provide first and second low frequency signals. The first and second low frequency signals are digitised using synchronised ADCs (30,32) to provide respective first and second digitised signals, the wider bandwidth signal being digitised at a higher sampling rate and the lower bandwidth signal being digitised at a lower sampling rate. The sampling rate of one of the first and second digitised signals is adjusted (44) to be the same as the other of the first and second digitised signals.

Abstract: In a radio communication system comprising a plurality of stations (100a,100b,100c) operating in a peer-to-peer mode, each station stores information relating to the transmission parameters of other stations. Such information may include the frequency offset and received signal strength of signals from the other stations. One station acts as central controller and allocates time slots for transmission from a first station (100a) to a second station (100b). Before the first station (100a) receives a signal from the second station (100b) it makes initial adjustments to its receiver circuitry depending on the stored information about previous signals received from that station (100b). This simplifies the task of adjusting the receiver circuitry during the preamble of the signal transmitted by the second station (100b).

Abstract: A protocol for forwarding data packets over a network. An originating transmitter sends a data packet over the network to a destination receiver. The packet is Transmit forwarded by one or more repeaters within the network. The repeaters assume responsibility for originating re-transmissions of the packet if the packet is not correctly received by the destination receiver (eg. if a NACK signal is returned from the receiver or if no type of acknowledgement signal is returned from the receiver). Re-transmission of the packet by multiple repeaters effectively modifies the data paths by which the data packet travels to the receiver increasing probability that the packet gets through to the receiver. The transmitter may be configured not to respond to any NACK signals for packets it has sent, thereby transferring retransmission overhead and signalling overhead to the repeaters. This originating transmitter is a battery-powered device and the repeaters are not power limited.

Abstract: A system for wireless distribution of a broadcast program within a building comprises a distribution apparatus (110) for transmitting the program and at least one program receiving apparatus (160) for receiving the broadcast program. The program receiving apparatus may receive the broadcast program from a neighbouring distribution apparatus (210) when the distribution capacity of the home distribution apparatus is fully loaded with other programs. A program receiving apparatus receiving from a neighbouring distribution apparatus may discontinue that reception when the broadcast program can be made available from its home distribution apparatus, or when the distribution capacity is required for a neighbouring program receiving apparatus for a different program.

Abstract: A method of operating a radio communication system uses orthogonal signals for transmission of packets of data between two or more stations. In the transmitter data is encoded onto a plurality of orthogonal carriers by a differential phase modulation technique, for example DQPSK. The carriers are combined into a single signal by an inverse discrete Fourier transform and clipped at a predetermined amplitude before being transmitted to reduce the crest factor of the transmitted signal. The phase of one or more of the carriers is randomized before each data packet, hence a different crest factor will result for retransmissions of the same packet. This ensures that if a packet is difficult to transmit, because of reduced signal to noise ratio caused by clipping, it will retransmit successfully.

Abstract: A radio local area network(LAN) comprises a plurality of plug and play operating devices(OD1 to OD4), such as TV, STB, VCR and PC, one of which devices functions as a central controller(CC) which sets up time division digital data links between the operating devices in response to activating a suitable man/machine interface, for example an infra-red TV remote controller(RC). Those of the operating devices capable of operating as a central controller have stores(32) for storing power-on data so that in the event of the current central controller becoming de-energised an arbitration process is invoked whereby the operating device having the best power-on history becomes the new central controller. In a refinement, the arbitration process may be invoked when an operating device joins the radio LAN but in order to deter too many changes in central controllers the history of the current central controller is weighted.

Abstract: A wireless local area network system comprises an ATM switch (10) coupled to an access point (12) having a transceiver and a plurality of mobile terminals (14) each having a transceiver. The transceivers operate in accordance with an Orthogonal Frequency-Division Multiplexing (OFDM) transmission scheme having a plurality of channels. In response to the access point (12) polling the mobile terminals (14) enquiring if they want a time slot in the next down-link frame, those mobile terminals wanting a time slot transmit an E-burst on selected ones of the plurality of channels whose phases are selected to minimise the transmitted peak to mean envelope power. Optionally the E-burst can be modulated to provide a limited amount of signalling information.