Abstract: Wireless receiver systems and methods for user equipment are described that employ multiple receiver heads. The multiple heads can receive wireless communication signals over different receive paths from different transmission sources. The systems can scan and monitor signal quality from all receiver heads during a scheduled gap in a communication link without interfering with an ongoing communication session.

Abstract: Wireless receiver systems and methods for user equipment are described that employ multiple receiver heads. The multiple heads can receive wireless communication signals over different receive paths from different transmission sources. The systems can scan and monitor signal quality from all receiver heads during a scheduled gap in a communication link without interfering with an ongoing communication session.

Abstract: Wireless receiver systems and methods for user equipment are described that employ multiple receiver heads. The multiple heads can receive wireless communication signals over different receive paths from different transmission sources. The systems can scan and monitor signal quality from all receiver heads during a scheduled gap in a communication link without interfering with an ongoing communication session.

Abstract: A regenerative frequency divider comprising an in-phase mixer circuit and a phase-shifted mixer circuit. At least one switching device of the in-phase mixer circuit is of a smaller scale than a corresponding switching device of the transconductance component of the in-phase mixer circuit. In some examples, at least one switching device within an input switching stage of the regenerative frequency divider forming part of the phase-shifted mixer circuit is of a smaller scale than a respective corresponding switching device within the input switching stage forming part of the in-phase mixer circuit. In some further examples, all switching devices within the phase-shifted mixer circuit are of a small scale than respective corresponding switching devices within the in-phase mixer circuit.

Abstract: A bootstrap circuit for increasing the voltage swing of a local oscillator waveform signal. The bootstrap circuit comprises a driver stage for driving at an output thereof a local oscillator waveform signal having an increased voltage swing. The driver stage comprises a first supply voltage node and a second supply voltage node. The bootstrap circuit further comprises at least one energy storage component arranged to store energy within an energy storage element when the voltage level at the input node of the driver stage comprises the second voltage state and use the energy stored within the energy storage element to generate an increased voltage level, and to apply the increased voltage level to the first supply voltage node of the driver stage when the voltage level at the input node of the driver stage comprises the first voltage state.

Abstract: A bootstrap circuit for increasing the voltage swing of a local oscillator waveform signal. The bootstrap circuit comprises a driver stage for driving at an output thereof a local oscillator waveform signal having an increased voltage swing. The driver stage comprises a first supply voltage node and a second supply voltage node. The bootstrap circuit further comprises at least one energy storage component arranged to store energy within an energy storage element when the voltage level at the input node of the driver stage comprises the second voltage state and use the energy stored within the energy storage element to generate an increased voltage level, and to apply the increased voltage level to the first supply voltage node of the driver stage when the voltage level at the input node of the driver stage comprises the first voltage state.

Abstract: A method of calibrating an envelope tracking system for a supply voltage for a power amplifier module within a radio frequency (RF) transmitter module of a wireless communication unit. The method includes, within at least one signal processing module of the wireless communication unit, determining combinations of the power amplifier supply voltage and power amplifier input power that provide a power amplifier output power equal to a target output power, obtaining battery current indications for the determined combinations of the power amplifier supply voltage and power amplifier input power, selecting a combination of the power amplifier supply voltage and power amplifier input power that provide a power amplifier output power equal to a target output power based at least partly on the obtained battery current indications therefore, and calibrating the envelope tracking system using the selected combination of the power amplifier supply voltage and power amplifier input power.

Abstract: A method of calibrating an envelope tracking system for a supply voltage for a power amplifier module within a radio frequency (RF) transmitter module. The method includes deriving a mapping function between an instantaneous envelope of a waveform signal to be amplified by the power amplifier module and the power amplifier module supply voltage to achieve a constant power amplifier module gain based on a gain compression factor, setting an envelope tracking path of the transmitter module into an envelope tracking mode in which mapping between the instantaneous envelope of the waveform signal and the power amplifier module supply voltage is performed using the derived mapping function, applying a training signal comprising an envelope that varies with time to the RF transmitter module, measuring a battery current, modifying the gain compression factor based on the measured battery current, and re-deriving the mapping function based on the modified gain compression factor.

Abstract: An integrated circuit comprises a radio frequency (RF) power amplifier (PA) output stage; at least one amplifier stage prior to the RF PA output stage; a linear amplifier comprising a voltage feedback wherein the linear amplifier is operably coupled to a low frequency supply module such that the linear amplifier and low frequency supply module provide a combined first power supply to the RF PA output stage; and a switched mode power supply module arranged to provide a second power supply to the linear amplifier and to the at least one amplifier stage prior to the RF PA output stage.

Abstract: An integrated circuit comprises a radio frequency (RF) power amplifier (PA) output stage; at least one amplifier stage prior to the RF PA output stage; a linear amplifier comprising a voltage feedback wherein the linear amplifier is operably coupled to a low frequency supply module such that the linear amplifier and low frequency supply module provide a combined first power supply to the RF PA output stage; and a switched mode power supply module arranged to provide a second power supply to the linear amplifier and to the at least one amplifier stage prior to the RF PA output stage.

Abstract: A signal processing circuit has a first circuit, a digital-to-analog converter (DAC) and a second circuit. The first circuit receives a digital input signal with a non-zero direct current (DC) component, and subtracts at least a portion of the DC) component of the received digital input signal from the received digital input signal. The DAC is operably coupled to the first circuit, and arranged to perform a digital-to-analog conversion upon an output of the first circuit. The second circuit is operably coupled to the DAC, and arranged to add a DC component to an analog output signal derived from an output of the DAC. The signal processing circuit may be part of an integrated circuit or a wireless communication unit.

Abstract: An integrated circuit for providing a differential interface for an envelope tracking signal is described. The integrated circuit includes a subtraction module having a first input for receiving a digital envelope tracking signal and a second input for receiving a second signal, wherein the subtraction module is arranged to subtract the second signal from the digital envelope tracking signal and produce an envelope tracking signal with a reduced average direct current (DC) component; a digital-to-analog converter (DAC) arranged to receive the envelope tracking signal with the reduced average DC component and produce a differential analog version thereof; and a modulator operably coupled to a differential output of the DAC, wherein the modulator comprises a DC input point arranged to insert a DC component into the differential analog version of the envelope tracking signal.

Abstract: An integrated circuit for providing a differential interface for an envelope tracking signal is described. The integrated circuit includes a subtraction module having a first input for receiving a digital envelope tracking signal and a second input for receiving a second signal, wherein the subtraction module is arranged to subtract the second signal from the digital envelope tracking signal and produce an envelope tracking signal with a reduced average direct current (DC) component; a digital-to-analog converter (DAC) arranged to receive the envelope tracking signal with the reduced average DC component and produce a differential analog version thereof; and a modulator operably coupled to a differential output of the DAC, wherein the modulator comprises a DC input point arranged to insert a DC component into the differential analog version of the envelope tracking signal.

Abstract: An apparatus for biasing a transistor, comprising: a controllable bias generator; a test circuit; a digital Mth order differentiator responsive to an output of the test circuit; and a controller responsive to the digital Mth order differentiator for controlling the controllable bias generator; wherein the test circuit is configured to calculate an Lth order derivative of the transistor's performance.

Abstract: Methods and apparatus are provided for controlling transmitted power in a wireless system. The method includes generating information to be transmitted as a series of signal bursts, with a time interval between successive signal bursts, controlling individually a power level of each of said signal bursts with a power control signal to provide output signal bursts to be transmitted, and asserting a new power value of the power control signal during the time interval preceding each signal burst. The wireless system can be a TDSCDMA wireless system, and the signal bursts can be uplink signal bursts.

Abstract: An apparatus for compensating for variations in loop gain of a phase locked loop as a function of frequency, comprising a correction calculator for introducing a loop gain correction as a function of target frequency of a oscillator controlled by the phase locked loop.

Abstract: An apparatus for biasing a transistor, comprising: a controllable bias generator; a test circuit; a digital Mth order differentiator responsive to an output of the test circuit; and a controller responsive to the digital Mth order differentiator for controlling the controllable bias generator; wherein the test circuit is configured to calculate an Lth order derivative of the transistor's performance.

Abstract: A dual mode transmitter for GSM and UMTS operation is provided. The GSM and UMTS paths share an oscillator and an intermediate frequency stage. Also, with the exception of the final stage of power amplification, the transmitter is provided as an integrated device.

Abstract: A frequency agile voltage controlled oscillator is provided in which amplitude control is performed by digitally controlling the current supplied to the oscillator from a current source (10). The use of digital control means that phase noise performance of the oscillator is not degraded by the introduction of noise from the current source controller.

Abstract: A dual mode transmitter for GSM and UMTS operation is provided. The GSM and UMTS paths share an oscillator and an intermediate frequency stage. Also, with the exceptio of the final stage of power amplification, the transmitter is provided as an integrated device.