Quantance, Inc.

Silego Technology Inc.

Mixcomm, Inc.

Digital Dynamics, Inc.

Vikas Vinayak

Serge Francois Drogi

Martin Tomasz

Mark R Gehring

Cary Renzema

Jeremy Lubkin

Frank A Lane

Aristotele Hadjichristos

Harish Krishnaswamy

Arun Sridhar Natarajan

Alex Minkovich

Nathan Willis John

David Kuneth Chow

Sidney Chan

Richard Casler

Serge François Drogi

A radio frequency measurement system comprises an analog-to-digital converter, a voltage-controlled oscillator, and a phase lock loop circuit. The analog-to-digital converter includes a first input to receive a radio frequency signal and includes a first output to provide a digital signal in response to the received radio frequency signal. The voltage-controlled oscillator includes a first input and includes a first output couped to the first input of the analog-to-digital converter to provide a sampling clock to the analog-to-digital converter. The phase lock loop circuit includes a first input to receive a distributed clock signal, includes a second input coupled to the first output of the voltage-controlled oscillator to receive the sampling clock, and includes an output coupled to the first input of the voltage-controlled oscillator to provide a phase locked signal to the voltage-controlled oscillator in response to the distributed clock signal and the sampling clock.

Synchronization of RF measurements in networked systems

Controllable radio frequency power amplifiers (RFPAs), e.g., in a Hybrid-MIMO array, which are being driven at lower power levels, are operated at conditions such that their inherent EVM and ACLR are intentionally further increased. This increase of inherent EVM and ACLR is done in a precise manner, and the increased inherent EVM and ACLR are cancelled or reduced by the EVM and ACLR of the input Array DPD signal. The net result is improved EVM and ACLR performance over a broader range of angles. Exemplary methods and apparatus for increasing distortion include individual or combinations of: i) changing the DC bias a RFPA based on average operating power level; ii) changing supply voltage, e.g. Vcc, of a RFPA based on average operating power level, iii) adding a controllable non-linear element, such as a diode or varactor, at the input of the RFPA, based on the average operating power.

Methods and apparatus for using signal pre-distortion with individual power amplifier (PA) control

A comparator system and a method for comparing an input signal and a reference signal are presented. The system has a controller to adjust a rising output delay and/or a falling output delay of a system output signal. The system output signal is dependent on the comparison between the input signal and the reference signal. This system provides a more efficient comparator with reduced power consumption whilst still providing the required rising output delay and falling output delay for a given application. Techniques used in prior art will always resort to running the comparators at a speed that supports the speed requirements in the worst case conditions and does not exploit any asymmetries in the required rising output delay and falling output delay for a given application. When these asymmetries are exploited, further increases in power efficiency can be achieved.

Comparator system

A power supply efficiently suppresses transient voltages by storing the maximum charge expected in the transient and releasing it during the transient event at a rate in an equal but opposite amount to the transient, preventing the battery voltage from collapsing. The described power supply provides improved efficiency compared to conventional architectures for transient suppression, thus increasing the length of time between battery charges and creating a better user experience.

Transient suppression with lossless steady state operation

An audio system comprises an audio driver configured to receive a target audio signal and a feedback signal and to generate an adjusted audio signal responsive to the target audio signal and the feedback signal. A loudspeaker is configured to convert the adjusted audio signal into acoustical sound. A test signal generator is configured to generate a test signal having a higher frequency than the target audio signal. The test signal causes a test current to flow through the loudspeaker. A current sensing circuit is configured to measure the test current flowing through the loudspeaker and to generate a current sense signal indicative of the test current. A feedback circuit is configured generates the feedback signal responsive to the current sense signal.

Reducing audio distortion in an audio system

A self-setting power supply monitors a supply current drawn by a power amplifier and sets a supply voltage based on the supply current to achieve efficient power operation. In order to maintain operation of the power amplifier above minimum operating conditions, the self-setting power supply sets the supply voltage to the minimum operating voltage when the supply current drops below a threshold bias current. When the supply current is above the threshold bias current, the self-setting power supply adjusts the supply voltage approximately proportionally to the supply current to maintain approximately constant gain of the power amplifier.

Self setting power supply using negative output impedance

An RF PA system that generates its own local characterization information. The RF PA system includes a PA to generate a RF output signal from a RF input signal, the PA powered by a supply voltage. A characterization block generates characterization information corresponding to a relationship between the supply voltage and performance (e.g., gain, power efficiency, distortion, receive band noise) of the RF PA system for a plurality of levels of one or more operating conditions (e.g., temperature, operating frequency, modulation format, antennae mismatch, etc.) of the RF PA system. An amplitude estimator block estimates an amplitude of the RF input signal. A supply control block generates a supply voltage control signal for controlling the supply voltage based on the characterization information and the amplitude of the RF input signal.

Envelope tracking system with internal power amplifier characterization

A power stabilization circuit including a first reference power supply, a second reference power supply, and a combiner circuit coupled to the first reference power supply and the second reference power supply. The first reference power supply is configured to receive a first control signal, generate a first reference signal based on the first control signal, and provide the first reference signal to a first output power supply. The second reference power supply is configured to receive a second control signal, generate a second reference signal based on the second control signal, and provide the second reference signal to a second output power supply. The combiner circuit is configured to generate a combined reference signal based on the first reference signal and the second reference signal and drive a reference load based on the combined reference signal.

Power stabilization circuit and method

A power supply system comprising a power stabilization stage configured to combine a first reference signal having a first frequency range with a second reference signal having a second frequency range that is different than the first frequency range to generate a combined reference for driving a reference load. A first power supply (e.g. SMPS) is configured to generate a first output based on the first reference signal. A second power supply (e.g. linear regulator) is configured to generate a second output based on the second reference signal. A power combiner circuit is configured to combine the first output with the second output to generate a combined output for driving an output load.

Stabilizing a power combining power supply system

A power amplifier power controller in the power amplifier system monitors various operating conditions of the power amplifier, and controls the output transmit power of the power amplifier by coordinated control of both the input drive level to the power amplifier and the gain of the power amplifier. The power amplifier power controller controls the input drive level to the power amplifier so that the input drive level does not change substantially while adjusting the gain of the power amplifier to maximize the transmit power. The power amplifier power controller may also adjust the input drive level by some portion of the overall change required to the power of the power amplifier, while adjusting the gain of the power amplifier by the remaining portion of such overall change.

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Menlo Park, CA, United States of America

Vikas Vinayak