Qualcomm Incorporated

Chenliang Du

Kai Liu

Xiangdong Zhang

Xinwei Wang

Antonino Scuderi

Yan Kit Gary Hau

Jisun Ryu

Guoqing Fu

Chunhu Zhang

Lei Ma

Certain aspects of the present disclosure are directed towards a signal processing circuit. The signal processing circuit generally includes: an impedance transformation circuit coupled between a first node and a second node; and an attenuation circuit including a first variable resistive element coupled between the first node and a reference potential node, and a second variable resistive element coupled between the second node and the reference potential node.

Attenuator using variable resistors

Disclosed is a radio frequency (RF) filter that vertically integrates an acoustic wave filter with an integrated passive device (IPD) filter. The acoustic wave filter provides selectivity at fundamental frequency band while the IPD filter provides rejection at harmonic frequency bands.

High harmonic performance radio frequency filter

An amplifier circuit includes an amplifier configured to receive a radio frequency (RF) input signal from an input node, a bias circuit comprising a reference transistor coupled between a reference current source and ground, and a bias transistor coupled to the reference transistor and configured to generate a main bias current to bias the amplifier, an input power sense circuit coupled to the input node, and an additional transistor coupled to the input power sense circuit and to the bias transistor, the additional transistor configured to generate an additional bias current to bias the amplifier, the additional bias current responsive to a power level of the RF input signal.

Radio frequency (RF) amplifier bias circuit

This disclosure provides systems, methods and apparatuses for characterizing and operating a power amplifier. Before being placed into operation, output phase and output gain characteristics of the power amplifier may be determined over various operating conditions including varying two independent control signals and a supply voltage. The output phase and output gain characteristics may be stored for later retrieval. The power amplifier may be operated by determining a control signal profile for the two independent control signals based on operating conditions and radio-frequency (RF) envelope information associated with an input signal received by the power amplifier. The independent control signals may be generated in accordance with the control signal profile.

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San Diego, CA, United States of America

Chenliang Du