Patent
Multi-mode amplifier system
Ian Stuart Robinson,Frank Winter +1 more
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TLDR
In this article, an amplifier system switches between modes of operation based upon a characteristic of an input signal relative to a first threshold level and a second threshold level, and a mode selector selects the operation mode by transmitting an amplitude modulated signal plus a variable headroom voltage to a supply terminal of a power amplifier during the envelope tracking mode, an amplitude and phase modulated input signal during the polar mode and a substantially constant amplitude signal to the supply terminal during the linear mode.Abstract:
An amplifier system is provided that switches between a linear mode of operation, an envelope tracking mode of operation and a polar mode of operation. The amplifier system switches between modes of operation based upon a characteristic of an input signal relative to a first threshold level and a second threshold level. A mode selector selects the operation mode by transmitting an amplitude modulated signal plus a variable headroom voltage to a supply terminal of a power amplifier during the envelope tracking mode, an amplitude modulated signal to the supply terminal and phase modulated input signal during the polar mode and a substantially constant amplitude signal to the supply terminal during the linear mode.read more
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Patent
Envelope tracking amplifier circuit
TL;DR: In this article, an envelope tracking (ET) amplifier circuit is described, which includes ET tracker circuitry configured to provide an ET modulated voltage to an amplifier circuit for amplifying a radio frequency (RF) signal.
Patent
Multimode transmitter, module, communication device and chip set
Simo Murtojärvi,Tapani Ekman +1 more
TL;DR: In this article, a multimode transmitter consisting of generating means for generating signals according to different communication standards, amplifying means for amplifying the signals generated according to the different communications standards, and conveying means for conveying the signals from the generating means to the amplifying mean, the conveying signals being shared by the generated signals generated by the different communication standard.
Patent
Snubber for a direct current (dc)-dc converter
Jean-Christophe Berchtold,Chris Levesque,William David Southcombe,David E. Jones,Scott Yoder,Terry J. Stockert +5 more
TL;DR: In this paper, the first switching power supply includes a first switching converter, an energy storage element, a first inductive element, coupled between the switching converter and the energy storage elements, and a first snubber circuit.
Patent
Methods and Apparatus for Reducing the Average-to-Minimum Magnitude Ratio of Communications Signals in Communications Transmitters
TL;DR: In this paper, the average-to-minimum magnitude ratio (AMR) reduction circuit is configured to compare a magnitude of a local minimum of samples of the baseband signal to various magnitude threshold levels, and to modify the signal in one of two manners depending on the relationship of the magnitude of the local minimum and the various threshold levels.
References
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Journal ArticleDOI
High-efficiency power amplifier using dynamic power-supply voltage for CDMA applications
TL;DR: In this article, a boost DC-DC converter with an operating frequency of 10 MHz is demonstrated using GaAs heterojunction bipolar transistors, and an envelope detector circuit with a fast feedback loop regulator is discussed.
Patent
Method and apparatus for operating a radio-frequency power amplifier as a variable-class linear amplifier
TL;DR: In this paper, a variable-class linear amplifier (600, 800, 900) applies a supply type of envelope modulation to an RF power amplifier operating in or near compression at highest envelope amplitudes, and transitions gradually to an envelope tracking type of operation at intermediate amplifier amplitudes.
Patent
Method and apparatus for generating a linearly modulated signal using polar modulation
Bengt Lindoff,Hakan Eriksson +1 more
TL;DR: In this article, an apparatus and method for generating a linearly modulated signal in a polar modulation system is described, where a signal for transmission is separated into a phase component and an amplitude component, and a carrier signal is modulated with the phase component in a phase modulator, creating a phase distortion.
Patent
RF transmitter with extended efficient power control range
TL;DR: A highly efficient radio frequency (RF) transmitter provides both wide bandwidth and an extended power control range as mentioned in this paper, which is useful in wireless communications to increase both handset talk time and battery life.
Patent
Method, device, phone and base station for providing envelope-following for variable envelope radio frequency signals
Pallab Midya,Lawrence E. Connell,Steven F. Gillig,John Grosspietsch,Andrew Merritt Khan,George Francis Opas,Robert Louis Palandech +6 more
TL;DR: In this paper, an envelope-following unit is used to output a supply voltage in accordance with a variable envelope of an input baseband signal, wherein using the efficient envelope following unit includes: 1) using a bandwidth-limiting mapping unit to determine a reference signal based on the base band signal; and 2) using an envelope tracking power converter to output the supply voltage, responsive to the reference signal, to the linear RF power amplifier.