RF amplifier having a transition shaping filter
First Claim
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1. A radio frequency (RF) power amplifier system, comprising:
- an RF amplifier;
a digital-to-RF modulator to generate an RF input signal for the RF amplifier based on at least one modulator control signal;
a voltage control unit configured to provide a variable supply voltage to the RF amplifier in response to at least one voltage control signal, the variable supply voltage being selected from a plurality of discrete voltage levels;
a controller to provide the at least one modulator control signal to the digital-to-RF modulator and the at least one voltage control signal to the voltage control unit based, at least in part, on data to be amplified by the RF amplifier; and
a transition shaping filter coupled between the RF amplifier and the voltage control unit, said transition shaping filter to filter a variable supply voltage to be applied to the RF amplifier so as to provide shaping and/or bandwidth limitation of the voltage transitions between discrete voltage levels,wherein the transition shaping filter is configured to reduce frequency content at an output of the RF amplifier by shaping the voltage transitions between discrete voltage levels of the variable supply voltage provided to the RF amplifier.
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Abstract
A radio frequency (RF) power amplifier system or transmitter includes one or more power amplifiers and a controller that is configured to adjust amplitudes and phases of RF input signals of the one or more power amplifiers and supply voltages applied to the one or more power amplifiers. In embodiments where multiple power amplifiers are used, a combiner may be provided to combine outputs of the power amplifiers.
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Citations
18 Claims
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1. A radio frequency (RF) power amplifier system, comprising:
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an RF amplifier; a digital-to-RF modulator to generate an RF input signal for the RF amplifier based on at least one modulator control signal; a voltage control unit configured to provide a variable supply voltage to the RF amplifier in response to at least one voltage control signal, the variable supply voltage being selected from a plurality of discrete voltage levels; a controller to provide the at least one modulator control signal to the digital-to-RF modulator and the at least one voltage control signal to the voltage control unit based, at least in part, on data to be amplified by the RF amplifier; and a transition shaping filter coupled between the RF amplifier and the voltage control unit, said transition shaping filter to filter a variable supply voltage to be applied to the RF amplifier so as to provide shaping and/or bandwidth limitation of the voltage transitions between discrete voltage levels, wherein the transition shaping filter is configured to reduce frequency content at an output of the RF amplifier by shaping the voltage transitions between discrete voltage levels of the variable supply voltage provided to the RF amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In an apparatus comprising a non-transitory computer readable medium having instructions stored thereon that, when executed by a computer, perform a method for operating an RF transmitter having a digital-to-radio frequency (RF) modulator driving a power amplifier, the method comprising:
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obtaining transmit data to be transmitted from the RF transmitter; providing input information for the digital-to-RF modulator based, at least in part, on the transmit data, the input information to control an amplitude and a phase of an RF output signal of the digital-to-RF modulator; selecting a supply voltage for the power amplifier based, at least in part, on the transmit data, the supply voltage being selected from a plurality of discrete voltage levels, wherein selecting a supply voltage includes making a decision about supply voltage level for the RF power amplifier based, at least in part, on a window of data samples representing data to be transmitted by the RF transmitter; and filtering the variable supply voltage to be applied to the RF amplifier with a transition shaping filter so as to provide shaping and/or bandwidth limitation of the voltage transitions between discrete voltage levels, wherein the filtering comprises reducing, by the transition shaping filter, frequency content at an output of the RF amplifier by shaping the voltage transitions between discrete voltage levels of the variable supply voltage provided to the RF amplifier. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification