Abstract: A receiver front-end includes a receive path configured to receive an input signal. Additionally, the receiver front-end also includes a low noise amplifier having a common input stage and multiple separate output stages, wherein each separate output stage is configured to be separately activated and connected to a receive signal mixer that provides signal demodulation of the input signal employing one of an aggregation of receiver carriers. A method of operating a receiver front-end and a receiver front-end system are also provided.

Abstract: A sigma-delta analog-to-digital converter includes an input transconductance stage that provides an analog input current proportional to an analog input voltage and a current summing stage that generates an analog error signal corresponding to a difference between the analog input current and a feedback current. The sigma-delta analog-to-digital converter also includes a forward signal path that processes the analog error signal to provide a digital output signal corresponding to the analog input voltage. Additionally, the sigma-delta analog-to-digital converter includes a feedback path that includes a current steering digital-to-analog converter having both sourcing and sinking current sources, wherein currents provided by the sourcing and sinking current sources are steerable and connected to directly provide the feedback current based on the digital output signal. A sigma-delta analog-to-digital converter operating method is also provided.

Abstract: A digital frequency synthesizer with an automatic calibration system. The digital frequency synthesizer is calibrated by initiating a coarse tuning operation to rapidly reach a preliminary frequency that is proximate to the desired final frequency. A calibration procedure is then executed for adjusting gain in the frequency synthesizer based on the preliminary frequency. This test involves applying one or more test signals to the frequency synthesizer and measuring a signal generated in the frequency synthesizer. This measured signal corresponds to a gain response of the circuit at the preliminary frequency. When the expected gain is known, any difference relative to the gain of the measured signal is used to adjust the gain in a circuit of the frequency synthesizer such that the actual gain substantially matches the expected gain.

Abstract: A method of envelope tracking and an envelope tracking (ET) circuit. One embodiment of the (ET) circuit is for radio frequency (RF) transmission and includes: (1) an amplitude calculator configured to generate an amplitude signal that approximates the amplitude of an input signal, (2) a peak detector configured to take samples of the amplitude signal within a time window and produce an envelope signal that represents an amplitude peak among the samples, and (3) a signal conditioner configured to condition the envelope signal for driving a power supply input stage of a power amplifier operable to amplify and transmit an RF signal based on the input signal.

Abstract: A transmitter architecture having a single signal path or hardware to cover WCDMA/EDGE/GSM applications, and requires no SAW at the transmitter outputs. The transmitter architecture allows for a transmit convergence feature. A passive mixer with unique driver and furthermore using native devices available from the CMOS process for the mixer cores enables low voltage and low power design, low output noise and high linearity. A digital variable gain amplifier has the capability to cover wide output dynamic range operated from low supply voltage and interfaced digitally with the baseband circuit without DAC. A single transformer is used to combine the outputs from the WCDMA/EDGE and GSM drivers and subsequently convert the differential signal paths into a single-ended signal. RF switches are used to divert the output from the transformer to different bands and applications.

Abstract: A power supply noise rejection circuit for functional circuits, such as a voltage controlled oscillator (VCO). The power supply noise rejection circuit includes an isolation transistor connected to a voltage supply for providing an output current and voltage substantially free of noise across the full frequency range. A current source, a diode connected reference transistor with resistance means connected between its gate and drain terminals, and a dummy circuit serially connected between the voltage supply and ground generate a bias voltage that is applied to the gate of the isolation transistor. The dummy circuit mimics the DC characteristics of the functional circuit such that the output current tracks with process and temperature variations. The isolation transistor and the reference transistor can have negative threshold voltages, and the circuit can include bleed means for drawing current from the gate of the reference transistor and isolation transistor.

Abstract: A method, device and computer program product is provided for sending a data signal and a clock signal between a radio frequency circuit of a device and a baseband circuit of the device, the radio frequency circuit being configured for at least one of transmission and reception of radio signals in a radio frequency band, where the clock signal has a clock frequency Fc. The method comprises selecting the clock frequency Fc to be a rational multiple of the 0.270833 MHz symbol rate of the Global System for Mobile Communications (GSM) standard and a rational multiple of the 3.84 MHz chipping rate of the Wideband Code Division Multiple Access (WCDMA) interface. The clock frequency Fc is selected such that the clock signal can be generated using a 38.4 MHz or 19.2 MHz reference clock signal, a non-fractional Phase Locked Loop clock multiplier and an output divider, without first having to divide down the reference clock signal.

Abstract: A closed loop power output calibration system for variable power output wireless devices. The wireless device includes a wireless transceiver having a transmit core coupled to a discrete power amplifier. Power detection circuitry formed in the wireless transceiver provides a detected power level of the power amplifier, and a reference power level, both of which are converted to digital signals using existing I and Q signal analog to digital converters in the receiver core. The digital signals are processed to cancel power distortion and temperature effects to provide a resulting power feedback signal. Corrective control signals are generated in response to the power feedback signal relative to a desired power output level. The gain in the transmit core is then adjusted in response to the corrective control signals such that the power amplifier outputs the target output power level.

Abstract: A driver circuit for supplying a drive signal to a mixer circuit comprising a first and second circuit branch and an operational amplifier. The first circuit branch receives an input signal and a bias signal. The second circuit branch receives the input signal. The operational amplifier has a first input connected to a junction node of the first circuit branch and a second input connected to a junction node of the second circuit branch. The operational amplifier is arranged to provide an operational amplifier output signal a second component of the second circuit branch so that a voltage at the junction node of the second circuit branch is equal to a voltage at the junction node of the first circuit branch. The voltage is dependent on the input signal and providing the drive signal.

Abstract: A digital linear transmitter for digital to analog conversion of a radio frequency signal. The transmitter includes a delta sigma (??) digital to analog converter (DAC) and a weighted signal digital to analog converter in the transmit path of a wireless device to reduce reliance on relatively large analog components. The ?? DAC converts the lowest significant bits of the oversampled signal while the weighted signal digital to analog converter converts the highest significant bits of the oversampled signal. The transmitter core includes components for providing an oversampled modulated digital signal which is then subjected to first order filtering of the oversampled signal prior to generating a corresponding analog signal. The apparatus and method reduces analog components and increases digital components in transmitter core architecture of wireless RF devices.

Abstract: An apparatus and method for generating complementary periodic signals for a mixer circuit is provided. The apparatus comprises first and second generation circuits each for generating a periodic signal with a transition time on each rising edge different than a transition time on each falling edge. Each of the first and second generation circuits has an output for supplying its periodic signal to a mixer such that each rising edge of a periodic signal from one of the circuits crosses each falling edge of a periodic signal from the other of the circuits at a crossing point below a turn on voltage of the mixer.

Abstract: A driver circuit for supplying a drive signal to a mixer circuit comprising a first and second circuit branch and an operational amplifier. The first circuit branch receives an input signal and a bias signal. The second circuit branch receives the input signal. The operational amplifier has a first input connected to a junction node of the first circuit branch and a second input connected to a junction node of the second circuit branch. The operational amplifier is arranged to provide an operational amplifier output signal a second component of the second circuit branch so that a voltage at the junction node of the second circuit branch is equal to a voltage at the junction node of the first circuit branch. The voltage is dependent on the input signal and providing the drive signal.

Abstract: A power supply noise rejection circuit for functional circuits, such as a voltage controlled oscillator (VCO). The power supply noise rejection circuit includes an isolation transistor connected to a voltage supply for providing an output current and voltage substantially free of noise across the full frequency range. A current source, a diode connected reference transistor with resistance means connected between its gate and drain terminals, and a dummy circuit serially connected between the voltage supply and ground generate a bias voltage that is applied to the gate of the isolation transistor. The dummy circuit mimics the DC characteristics of the functional circuit such that the output current tracks with process and temperature variations. The isolation transistor and the reference transistor can have negative threshold voltages, and the circuit can include bleed means for drawing current from the gate of the reference transistor and isolation transistor.

Abstract: An adaptive current control circuit for reduced power consumption and minimized gain shift in a variable gain amplifier. An automatic gain control circuit provides gain control voltages in response to a gain control signal. The gain control voltages are used by the variable gain amplifier to set the gain of the output signal for wireless transmit operations. The adaptive current control circuit receives the same gain control voltages for reducing current to the variable gain amplifier during low gain operation, while providing higher currents during high gain operation. The current that is provided is a hybrid mix of proportional to absolute temperature (PTAT) current and complementary to absolute temperature (CTAT) current for minimizing temperature effects on the gain. The ratio of PTAT current and CTAT current is adjustable for specific temperature ranges to further minimize temperature effects on the gain.

Abstract: A transmitter architecture having a single signal path or hardware to cover WCDMA/EDGE/GSM applications, and requires no SAW at the transmitter outputs. The transmitter architecture allows for a transmit convergence feature. A passive mixer with unique driver and furthermore using native devices available from the CMOS process for the mixer cores enables low voltage and low power design, low output noise and high linearity. A digital variable gain amplifier has the capability to cover wide output dynamic range operated from low supply voltage and interfaced digitally with the baseband circuit without DAC. A single transformer is used to combine the outputs from the WCDMA/EDGE and GSM drivers and subsequently convert the differential signal paths into a single-ended signal. RF switches are used to divert the output from the transformer to different bands and applications.

Abstract: A digital frequency synthesizer with an automatic calibration system. The digital frequency synthesizer is calibrated by initiating a coarse tuning operation to rapidly reach a preliminary frequency that is proximate to the desired final frequency. A calibration procedure is then executed for adjusting gain in the frequency synthesizer based on the preliminary frequency. This test involves applying one or more test signals to the frequency synthesizer and measuring a signal generated in the frequency synthesizer. This measured signal corresponds to a gain response of the circuit at the preliminary frequency. When the expected gain is known, any difference relative to the gain of the measured signal is used to adjust the gain in a circuit of the frequency synthesizer such that the actual gain substantially matches the expected gain.

Abstract: A passive CMOS differential mixer circuit with a mismatch correction circuit for balancing the electrical characteristics of the two output paths. Once the output paths of the differential circuit are balanced, or matched as closely as possible, second order intermodulation product generation can be inhibited or at least reduced to acceptable levels. The mismatch correction circuit receives a digital offset signal, and generates one or more voltage signals to be selectively applied to the signal paths of the passive differential mixer circuit. The voltage signals can be adjusted back gate bias voltages applied to the bulk terminals of selected transistors to adjust their threshold voltages, or the voltage signals can be adjusted common mode voltages applied directly to a selected signal path. Since the differential mixer circuit is passive, no DC current contribution to noise is generated.

Abstract: An integrated automatic IIP2 calibration architecture for wireless transceivers is disclosed. The architecture enables a wireless transceiver to generate a test radio frequency (RF) signal having a second order tone with minimal additional circuitry. In particular, the test RF signal is generated using a combination of native transceiver circuits and test adaptor circuits. Native transceiver circuits are those circuits implemented on the transceiver chip for executing native transceiver functions during normal operation, which can be used for generating the test (RF) signal. Test adaptor circuits are added to the transceiver chip, more specifically to the native circuits, for enabling the native circuits to generate the test RF signal in a self-test mode of operation. Circuits for implementing a particular IIP2 minimizing scheme can be included on the transceiver chip for automatic IIP2 calibration during the self-test mode of operation.

Abstract: An adaptive current control circuit for reduced power consumption and minimized gain shift in a variable gain amplifier. An automatic gain control circuit provides gain control voltages in response to a gain control signal. The gain control voltages are used by the variable gain amplifier to set the gain of the output signal for wireless transmit operations. The adaptive current control circuit receives the same gain control voltages for reducing current to the variable gain amplifier during low gain operation, while providing higher currents during high gain operation. The current that is provided is a hybrid mix of proportional to absolute temperature (PTAT) current and complementary to absolute temperature (CTAT) current for minimizing temperature effects on the gain. The ratio of PTAT current and CTAT current is adjustable for specific temperature ranges to further minimize temperature effects on the gain.

Abstract: A closed loop power output calibration system for variable power output wireless devices. The wireless device includes a wireless transceiver having a transmit core coupled to a discrete power amplifier. Power detection circuitry formed in the wireless transceiver provides a detected power level of the power amplifier, and a reference power level, both of which are converted to digital signals using existing I and Q signal analog to digital converters in the receiver core. The digital signals are processed to cancel power distortion and temperature effects to provide a resulting power feedback signal. Corrective control signals are generated in response to the power feedback signal relative to a desired power output level. The gain in the transmit core is then adjusted in response to the corrective control signals such that the power amplifier outputs the target output power level.