Abstract: A method of operating a radio-frequency (RF) circuitry and a signal-processing circuitry in a mobile telephone apparatus includes at least partially disabling the signal-processing circuitry while transmitting or receiving signals. In one example, a processor is efficiently disabled by generating and servicing an interrupt of relatively high priority. One advantage of this example is that preexisting, legacy code can be maintained, while still achieving the desired objectives. The processor can be enabled by generating and servicing a second high priority interrupt.

Abstract: Radio-frequency (RF) apparatus includes receiver analog circuitry that receives an RF signal and provides at least one digital signal to receiver digital circuitry that functions in cooperation with the receiver analog circuitry. The receiver analog circuitry and the receiver digital circuitry are partitioned so that interference effects between the receiver analog circuitry and the receiver digital circuitry tend to be reduced.

Abstract: A communication apparatus includes a radio frequency circuit that operates on a radio frequency signal and a digital processing circuit coupled to the radio frequency circuit. The digital processing circuit includes a plurality of bus masters coupled to a shared bus. A bus arbiter is provided for arbitrating between requests to access the bus by a first bus master and one or more other bus masters. Accesses by the one or more other bus masters to the bus are restricted in response to a signal indicative of a change in a mode of operation of the RF circuit. In one particular implementation, a communication apparatus employs time domain isolation wherein the digital processing circuit may be placed in a shutdown mode when the radio frequency circuit is active.

Abstract: A method and apparatus is provided for use in a time domain isolated apparatus in which the operation of various radio-interfering circuits can be altered or controlled to mitigate levels of interference to the radio to acceptable levels based on current or predicted link requirements. Techniques are provided that allow some use of signal processing and other digital circuitry while the RF circuitry is operating.

Abstract: A method and apparatus is provided for use in a time domain isolated apparatus in which the operation of various radio-interfering circuits can be altered or controlled to mitigate levels of interference to the radio to acceptable levels based on current or predicted link requirements. Techniques are provided that allow some use of signal processing and other digital circuitry while the RF circuitry is operating.

Abstract: Radio-frequency (RF) apparatus includes receiver analog circuitry that receives an RF signal and provides at least one digital signal to receiver digital circuitry that functions in cooperation with the receiver analog circuitry. The receiver analog circuitry and the receiver digital circuitry are partitioned so that interference effects between the receiver analog circuitry and the receiver digital circuitry tend to be reduced.

Abstract: In one embodiment, the present invention includes a method for performing a test on a rechargeable battery to indirectly determine a state of protection circuitry associated with the battery. The method may discharge the battery by controlling a pull-down current into a system, determine if the battery voltage falls below a first threshold level within a predetermined amount of time, and if so provide a pre-charge current to the battery.

Abstract: A communication apparatus includes a radio frequency circuit that operates on a radio frequency signal and a digital processing circuit coupled to the radio frequency circuit. The digital processing circuit includes a first timing circuit that provides timed signals to control timing of system operations during an active mode of operation of the digital processing circuit, and a second timing circuit that provides timing signals to control timing of system operations during an active mode of operation of the radio frequency circuit. In one particular embodiment, at least a portion of the first timing circuit is disabled when the radio frequency circuit is active (receiving and/or transmitting).

Abstract: Components of a radio-frequency (RF) apparatus including transceiver circuitry and frequency modification circuitry of a crystal oscillator circuit that generates a reference signal with adjustable frequency may be partitioned in a variety of ways, for example, as one or more separate integrated circuits. The frequency modification circuitry may be implemented as part of a crystal oscillator circuit that includes digitally controlled crystal oscillator (“DCXO”) circuitry and a crystal. The frequency modification circuitry may include at least one variable capacitance device and may be employed to generate a reference signal with adjustable frequency. The adjustable reference signal may be provided to other components of the RF apparatus and/or the RF apparatus may be configured to provide the adjustable reference signal to baseband processor circuitry.

Abstract: A radio-frequency receiver circuitry includes a down-converter circuitry, an analog-to-digital converter circuitry, and a DC offset reduction circuitry. The down-converter circuitry accepts a received radio-frequency signal and processes the radio-frequency signal to provide an in-phase down-converted signal and a quadrature down-converted signal to the analog-to-digital converter circuitry. The analog-to-digital converter circuitry converts the in-phase and quadrature down-converted signals to an in-phase digital output signal and a quadrature digital output signal, respectively. The DC offset reduction circuitry couples to the analog-to-digital converter circuitry, and tends to reduce a DC offset transmitted to the in-phase and quadrature digital output signals.

Abstract: Components of a radio-frequency (RF) apparatus including transceiver circuitry and frequency modification circuitry of a crystal oscillator circuit that generates a reference signal with adjustable frequency may be partitioned in a variety of ways, for example, as one or more separate integrated circuits. The frequency modification circuitry may be implemented as part of a crystal oscillator circuit that includes digitally controlled crystal oscillator (“DCXO”) circuitry and a crystal. The frequency modification circuitry may include at least one variable capacitance device and may be employed to generate a reference signal with adjustable frequency. The adjustable reference signal may be provided to other components of the RF apparatus and/or the RF apparatus may be configured to provide the adjustable reference signal to baseband processor circuitry.

Abstract: A low-noise current reference circuitry includes a voltage source, a current source, and a controller. The voltage source generates a reference voltage. The current source provides a low-noise output current in response to a control signal. The controller provides the control signal based at least in part on the relative magnitudes of the reference voltage and a voltage derived from the output current. A low-noise voltage reference circuitry includes a reference voltage source, a voltage source, and a controller. The reference voltage source generates a reference voltage. The voltage source provides a low-noise output voltage in response to a control signal. The controller provides the control signal based at least in part on the relative magnitudes of the output voltage and the reference voltage.

Abstract: Radio-frequency (RF) apparatus includes receiver analog circuitry that receives an RF signal and provides at least one digital signal to receiver digital circuitry that functions in cooperation with the receiver analog circuitry. The interface between the receiver analog circuitry and the receiver digital circuitry includes configurable signal lines that function as a serial interface, or as a data and clock signal interface, depending on the state of a control signal.

Abstract: A buffer circuitry buffers a radio-frequency (RF) signal. The buffer circuitry includes a complementary pair of switches and a power source. The a complementary pair of switches has an input terminal and output terminal. The input terminal of the complementary pair of switches responds to the RF signal. The output terminal of the complementary pair of switches couples to an output of the buffer circuitry. The power source includes a capacitor coupled to a current source. The power source couples to the complementary pair of switches. The power source supplies power to the complementary pair of switches in a manner that the buffer circuitry supplies a substantially constant power level at its output.

Abstract: The invention can utilize a switching power regulator and a non-switching power regulator in conjunction to provide regulated power to the digital logic. The digital logic and switching regulator may be deactivated during RF activity so that interference from both the digital circuitry and the switching regulator is significantly reduced. The state of the digital circuitry may be maintained during this standby period by using the non-switching power regulator to provide an as-required leakage current to the digital circuitry in order to maintain state. After the RF event (e.g. sending or receiving data) has concluded, the switching regulator may be activated and digital processing continued using the digital logic with no loss of continuity.

Abstract: A radio-frequency (RF) apparatus capable of transmitting RF signals includes transmitter path circuitry. The transmitter path circuitry includes a voltage-controlled oscillator (VCO) that generates an output signal. The frequency of the output signal of the VCO circuitry is adjustable in response to a first control signal and a second control signal. The transmitter path circuitry also includes a first feedback circuitry and a second feedback circuitry that are responsive to the output signal of the VCO circuitry. The first feedback circuitry provides the first control signal to the VCO circuitry. The first control signal coarsely adjusts the frequency of the output signal of the VCO circuitry to a desired frequency. The second feedback circuitry supplies the second control signal to the VCO circuitry. The second control signal fine tunes the frequency of the output signal of the voltage-controlled oscillator circuitry to the desired frequency.

Abstract: A radio-frequency (RF) apparatus includes front-end circuitry. The front-end circuitry includes a filter circuitry and an impedance matching circuitry. The filter circuitry has a differential output that has an output impedance. The filter circuitry filters signals outside a signal band of interest. The impedance matching network has a differential input coupled to the output of the filter circuitry. The impedance matching network also has a differential output coupled to a signal processing circuitry. The signal processing circuitry has an input impedance. The impedance matching network matches the input impedance of the signal processing circuitry to the output impedance of the filter circuitry.

Abstract: A calibration circuitry includes an adjustable capacitor, a voltage generator, a reference voltage generator, and a controller. The reference voltage generator provides a reference voltage. The voltage generator provides a measurement voltage that depends on the capacitance of the adjustable capacitor. The capacitance of the adjustable capacitor varies in response to a control signal. The controller provides the control signal based on the relative values of the reference voltage and the measurement voltage.

Abstract: A radio-frequency (RF) receiver includes a receiver analog circuitry and a receiver digital circuitry coupled together. The receiver analog circuitry receives an RF signal. The receiver analog circuitry processes the received RF signal and generates a digital signal that it provides to the receiver digital circuitry. The receiver digital circuitry includes a digital down-converter circuitry that mixes the digital signal provided by a receiver analog circuitry with a digital intermediate frequency (IF) local oscillator signal to generate a digital down-converted signal. The receiver digital circuitry also includes a digital filter circuitry that filters the digital down-converted signal to generate a filtered digital signal. The digital filter circuitry provides a notch at a frequency that corresponds to a residual DC offset of the receiver analog circuitry.

Abstract: A radio-frequency (RF) apparatus capable of transmitting RF signals includes transmitter path circuitry. The transmitter path circuitry includes a voltage-controlled oscillator (VCO) circuitry. The VCO circuitry generates a first signal that has a first frequency. A divider circuitry couples to the VCO circuitry and, in response to the first signal, the divider circuitry generates a second signal that has a second frequency. The frequency of the second signal equals the frequency of the first signal divided by a number.