Abstract:
A variable frequency oscillator comprising: an oscillatory circuit for generating a periodic output dependent on the capacitance between a first node and a second node of the circuit, and having a capacitative element connected between the first node and the second node; the capacitative element comprising: a variable capacitance unit, the capacitance of which is variable for varying the frequency of the output and a plurality of finite capacitances each being selectively connectable in parallel with the variable capacitance unit between the first node and the second node to trim the frequency of the output.
Abstract:
A radio transmitter and/or receiver comprising: an oscillator tuning circuit comprising an adjustable capacitor whose capacitance is adjustable by means of a first tuning signal; a filter tuning circuit comprising an adjustable capacitor whose capacitance is adjustable by means of a second tuning signal; an oscillator whose operational frequency is dependant on the reactance of the oscillator tuning circuit; a filter for filtering signals in the course of transmission and/or reception, and whose response is dependant on the reactance of the filter tuning circuit; and a tuning unit for generating the first and second tuning signals; wherein at least a part of the filter tuning circuit is a replica of at least a part of the oscillator tuning circuit and the tuning circuit is capable of generating one of the first and second tuning signals in dependence on the other of the tuning signals.
Abstract:
A communication device for receiving a signal in the form of a series of bursts, each burst being at one of a plurality of different available transmission modes, the communication device comprising: two antennas; a receiver unit coupled to the antennas for preferentially receiving signals from a selected one of the antennas; and an antenna selection unit for selecting for each received burst with which of the antennas the receiver unit is to preferentially receive signals.
Abstract:
Method and peripheral device to facilitate the installation of software on a host device to allow communication between that host device and a peripheral device. On connection to a host device a peripheral device presents in a first mode. In the first mode the device identifies itself as a Human Interaction Device and transmits information to the host device to facilitate the installation of the software. Subsequently the peripheral device operates in a second mode in which it identifies itself according to its real function.
Abstract:
A radio receiver for receiving first signals of a first frequency spectrum having principal energy in a first frequency band and second signals of a second frequency spectrum having principal energy in second and third frequency bands, located on either side of the first frequency band, includes (i) an input for receiving an incoming signal; (ii) frequency shifting means for frequency shifting the incoming signal to form an intermediate frequency signal; and (iii) a filter for filtering the intermediate frequency signal. The filter has a frequency response that has a first passband and a second passband separated by a central stopband. A control unit for controlling the frequency shifting means has first and second modes for reception of the first and second signals. In the first mode, the control unit controls the frequency shifting means so as to frequency shift the incoming signal so that (a) the first frequency band of the incoming signal is shifted onto one of the first and second passbands and (b) one of the second and third frequency bands of the incoming signal is shifted onto the central stopband. In the second mode, the control unit controls the frequency shifting means so as to frequency shift the incoming signal so that (a) the second and third frequency bands of the incoming signal are shifted onto, respectively, the first and second passbands and (b) the first frequency band of the incoming signal is shifted onto the central stopband.
Abstract:
A fluid flow meter comprises a pair of transducers spaced apart in the direction of fluid flow. A transmitter causes acoustic signals to be transmitted in both directions through the fluid by the transducers. A processor determines information relating to the fluid flow by monitoring the time of flight of acoustic signals received by the transducers. Part of the space between the transducers defines a flow path consisting of a flow structure having a plurality of parallel fluid flow passages which extend axially in the direction of flow, wherein the cross-sectional diameters of the passages are chosen such that substantially plane acoustic waves only are transmitted through the passages by the fluid, and wherein under working conditions the fluid flows through each passage such that the ratio of the volume flow rate through the passage to the total volume flow rate remains substantially constant with respect to the total volume flow rate.
Abstract:
Improved power control methods and power control systems are described wherein received RSSI values are processed to generate a power control signal which may be used by a link manager, or other element in a receiving station, to determine whether to send a power control message to the transmitting station. The method used to process the received RSSI values is dependent upon a value of the power measurement, for example, the method may involve a comparison between the value of the power measurement and a value of the power control signal. In another embodiment, the received RSSI values may be converted to power values and then smoothed using a filter.
Abstract:
Receiving a Wi-Fi radio signal using a Bluetooth receiver architecture. Also, adapting a Wi-Fi receiver architecture to constrain a received radio signal to less than the bandwidth of a conveyed Wi-Fi signal for subsequent processing purposes.
Abstract:
A radio transceiver comprising: an antenna; local oscillator for generating a local oscillator signal at a local oscillator frequency; a receiver capable of receiving a first radio frequency signal from the antenna at a receiver input and having a first mixer for mixing a signal derived from the first radio signal with the said local oscillator signal to generate an intermediate frequency signal, and a receiver output for providing an output signal dependant on the intermediate frequency signal; a transmitter capable of receiving an input signal at a transmitter input and having a second mixer for mixing a signal derived from the input signal with a local oscillator signal to generate a second radio frequency signal for transmission; a switching arrangement having a normal configuration in which the transmitter is coupled to the antenna to apply the second radio frequency signal to the antenna, and a testing configuration in which the transmitter is coupled to the receiver input to apply the second radio frequency signal to the receiver input; and a signal processor coupled to the transmitter input and the receiver output and capable of, when the switching arrangement is in the testing configuration, applying a testing signal to the transmitter input to cause the transmitter to generate a radio frequency test signal, and determining from the output signal of the receiver the response of the receive to the radio frequency test signal.
Abstract:
A fluid flow meter comprises a pair of transducers spaced apart in the direction of fluid flow. A transmitter causes acoustic signals to be transmitted in both directions through the fluid by the transducers. A processor determines information relating to the fluid flow by monitoring the time of flight of acoustic signals received by the transducers. Part of the space between the transducers defines a flow path consisting of a flow structure having a plurality of parallel fluid flow passages which extend axially in the direction of flow, wherein the cross-sectional diameters of the passages are chosen such that substantially plane acoustic waves only are transmitted through the passages by the fluid, and wherein under working conditions that fluid flows through each passage such that the ratio of the volume flow rate through the passage to the total volume flow rate remains substantially constant with respect to the total volume flow rate.