Linearized power amplifier
First Claim
1. A linearized power amplifier circuit comprising:
- a non-linear radio frequency (RF) power amplifier for amplifying an input signal and producing an output signal corresponding thereto, said input signal having envelope properties, said non-linear amplifier exhibiting non-linear amplitude and phase characteristics and having at least one operating point input;
dynamic bias modulation means for dynamically modulating the operation of said non-linear amplifier for efficient operation of said non-linear amplifier, said dynamic bias modulation means comprising, an input signal envelope determining means for obtaining an envelope signal from said input signal, mapping means for converting said envelope signal to at least one optimum operating voltage for said non-linear amplifier, and power driver means for applying said at least one operating voltage to said operating point input of said non-linear amplifier; and
linearization means which is separate and distinct from said dynamic bias modulation means, said linearization means utilizing a signal representation in said circuit that does not result in bandwidth expansion for linearizing and correcting for the non-linear amplitude and phase characteristics of said non-linear amplifier and further for correcting for additional distortion and errors introduced by said dynamic bias modulation means.
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Accused Products
Abstract
A linearized power amplifier is provided which comprises a non-linear radio frequency (RF) power amplifier, a linearization circuit such as a Cartesian Feedback circuit, an RF feedback circuit; an IF feedback circuit; or a feedforward circuit, and a dynamic bias modulation circuit for modulating an operating voltage of the amplifier. The dynamic bias modulation means includes an envelope determining circuit, signal processing circuits in which predetermined data or a simplified transfer function determined from measured characteristics of the amplifier is stored and used to produce power bias and/or base or gate bias signals, and driver circuits for modulating the power supply voltage and/or base or gate bias voltage of the RF amplifier in response to the bias signals. The dynamic bias modulation may be used with a BJT-based, and FET-based or any other type of RF power amplifier. With the right combination of power supply and base or gate bias modulation the efficiency of the RF amplifier can be maximised for a given output power, and the combination of linearization means and high level power supply and/or base or gate bias modulation gives the benefits of improved spectral control and intermodulation distortion reduction coupled with high efficiency.
245 Citations
17 Claims
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1. A linearized power amplifier circuit comprising:
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a non-linear radio frequency (RF) power amplifier for amplifying an input signal and producing an output signal corresponding thereto, said input signal having envelope properties, said non-linear amplifier exhibiting non-linear amplitude and phase characteristics and having at least one operating point input; dynamic bias modulation means for dynamically modulating the operation of said non-linear amplifier for efficient operation of said non-linear amplifier, said dynamic bias modulation means comprising, an input signal envelope determining means for obtaining an envelope signal from said input signal, mapping means for converting said envelope signal to at least one optimum operating voltage for said non-linear amplifier, and power driver means for applying said at least one operating voltage to said operating point input of said non-linear amplifier; and linearization means which is separate and distinct from said dynamic bias modulation means, said linearization means utilizing a signal representation in said circuit that does not result in bandwidth expansion for linearizing and correcting for the non-linear amplitude and phase characteristics of said non-linear amplifier and further for correcting for additional distortion and errors introduced by said dynamic bias modulation means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification