Method and device for modeling AM-AM and AM-PM characteristics of an amplifier, and corresponding predistortion method
First Claim
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1. A method of modeling the AM--AM and AM-PM characteristics of an amplifier including the following steps:
- transmitting a reference signal to said amplifier,digitizing the response of said amplifier to said reference signal to produce two sets of AM--AM and AM-PM reference samples, respectively,determining two series of polynomials respectively representative of the AM/AM and AM/PM characteristics from the samples, where the second derivatives of those polynomials and the distance between the samples points and the polynomials are used to define the curves.
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Abstract
A method of modeling the AM--AM and AM-PM characteristics of an amplifier includes the step of transmitting a reference signal to the amplifier. The response of the amplifier to the reference signal is digitized to produce two sets of AM--AM and AM-PM reference samples, respectively. Two series of polynomials respectively representative of the AM--AM and the AM-PM characteristics are determined from the samples. The determination of each polynomial allows for the second derivative of the polynomial and for the distances between the samples and points on the curve defined by the polynomial.
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10 Claims
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1. A method of modeling the AM--AM and AM-PM characteristics of an amplifier including the following steps:
- transmitting a reference signal to said amplifier,
digitizing the response of said amplifier to said reference signal to produce two sets of AM--AM and AM-PM reference samples, respectively, determining two series of polynomials respectively representative of the AM/AM and AM/PM characteristics from the samples, where the second derivatives of those polynomials and the distance between the samples points and the polynomials are used to define the curves. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- transmitting a reference signal to said amplifier,
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8. A device for modeling the AM--AM and AM-PM characteristics of an amplifier using a reference signal transmitted to said amplifier, including:
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means for digitizing the response of said amplifier to said reference signal delivering two sets of AM--AM and AM-PM reference samples, respectively, and means for determining two series of polynomials respectively representative of the AM/AM and AM/PM characteristics from the samples, where the second derivatives of those polynomials and the distance between the sampled points and the polynomials are used to define the curves.
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9. A method of predistorting a signal modulated with non-constant envelope modulation by modeling the AM--AM and AM-PM characteristics of an amplifier including the following steps:
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transmitting a reference signal at regular intervals to said amplifier, digitizing the response of said amplifier to said reference signal so as to produce two sets of AM--AM and AM-PM reference samples, respectively, determining two series of polynomials respectively representative of the AM/AM and AM/PM characteristics from the samples, where the second derivatives of those polynomials and the distance between the sampled points and the polynomials are used to define the curves. measuring a parameter representative of the signal to be transmitted, and predistortion multiplication of said signal to be transmitted in accordance with said polynomials and said representative parameter. - View Dependent Claims (10)
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Specification