Distortion compensating circuit for compensating distortion occurring in power amplifier
First Claim
1. A distortion compensating circuit for compensating distortion occurring in amplifying means equipped for a radio transmission device, comprising:
- power calculating and amplitude limitation judging means for calculating the power value of a quadrature baseband transmission signal, judging whether the power value thus calculated is not less than a predetermined power threshold value, outputting as a multiplication coefficient such a coefficient that the power value of the quadrature baseband transmission signal is equal to or less than the power threshold value when the power value thus calculated is larger than the power threshold value, and outputting as a multiplication coefficient such a coefficient that the quadrature baseband transmission signal is left unchanged when the power value thus calculated is not larger than the power threshold value;
amplitude maximum value limiting means for performing amplitude maximum value limitation based on circular clipping which is implemented by multiplying each of I and Q components of the quadrature baseband transmission signal by the multiplication coefficient from said power calculating and amplitude limitation judging means;
error calculation and compensation data renewing unit for performing the error calculation between the quadrature baseband transmission signal after the amplitude thereof has been limited by said amplitude maximum value limiting means and the quadrature baseband signal fed back from the output of said amplifying means to renew distortion compensation data for compensating non-linear distortion; and
non-linear distortion compensation calculating means for performing, on the basis of the compensation data from said error calculation and compensation data renewing means, distortion compensation on the quadrature baseband transmission signal after the amplitude thereof has been limited by said amplitude maximum value limiting means.
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Accused Products
Abstract
A power calculating and amplitude limitation judging portion 13 calculates the power value x of the digital quadrature baseband signal I, Q from a transmission data generator 1, and compares the power value x with a power threshold value y set by a threshold value setting portion 14 to judge whether amplitude limitation is needed or not. An amplitude maximum limiting portion 12 subjects the quadrature baseband signal from the transmission data generator 1 to the amplitude maximum value limitation based on the judgment result in the power calculating and amplitude limitation judging portion 13. Thereafter, the digital quadrature baseband signal which has been subjected to the amplitude maximum value limitation by the amplitude maximum value limiting portion 12 is subjected to the distortion compensation using complex multiplication based on the distortion compensation data by a non-linear distortion compensation calculator 2.
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Citations
10 Claims
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1. A distortion compensating circuit for compensating distortion occurring in amplifying means equipped for a radio transmission device, comprising:
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power calculating and amplitude limitation judging means for calculating the power value of a quadrature baseband transmission signal, judging whether the power value thus calculated is not less than a predetermined power threshold value, outputting as a multiplication coefficient such a coefficient that the power value of the quadrature baseband transmission signal is equal to or less than the power threshold value when the power value thus calculated is larger than the power threshold value, and outputting as a multiplication coefficient such a coefficient that the quadrature baseband transmission signal is left unchanged when the power value thus calculated is not larger than the power threshold value;
amplitude maximum value limiting means for performing amplitude maximum value limitation based on circular clipping which is implemented by multiplying each of I and Q components of the quadrature baseband transmission signal by the multiplication coefficient from said power calculating and amplitude limitation judging means;
error calculation and compensation data renewing unit for performing the error calculation between the quadrature baseband transmission signal after the amplitude thereof has been limited by said amplitude maximum value limiting means and the quadrature baseband signal fed back from the output of said amplifying means to renew distortion compensation data for compensating non-linear distortion; and
non-linear distortion compensation calculating means for performing, on the basis of the compensation data from said error calculation and compensation data renewing means, distortion compensation on the quadrature baseband transmission signal after the amplitude thereof has been limited by said amplitude maximum value limiting means. - View Dependent Claims (2, 3, 4, 5)
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6. A distortion compensating circuit for compensating distortion occurring in amplifying means equipped for a radio transmission device, comprising:
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amplitude calculating and amplitude limitation judging means for calculating the amplitude value of a quadrature baseband transmission signal, judging whether the amplitude value thus calculated is not less than a predetermined amplitude threshold value, outputting as a multiplication coefficient such a coefficient that the amplitude value of the quadrature baseband transmission signal is equal to or less than the amplitude threshold value when the amplitude value thus calculated is larger than the amplitude threshold value, and outputting as a multiplication coefficient such a coefficient that the quadrature baseband transmission signal is left unchanged when the amplitude value thus calculated is not larger than the amplitude threshold value;
amplitude maximum value limiting means for performing amplitude maximum value limitation based on circular clipping which is implemented by multiplying each of I and Q components of the quadrature baseband transmission signal by the multiplication coefficient from said amplitude calculating and amplitude limitation judging means;
error calculation and compensation data renewing unit for performing the error calculation between the quadrature baseband transmission signal after the amplitude thereof has been limited by said amplitude maximum value limiting means and the quadrature baseband signal fed back from the output of said amplifying means to renew distortion compensation data for compensating non-linear distortion; and
non-linear distortion compensation calculating means for performing, on the basis of the compensation data from said error calculation and compensation data renewing means, distortion compensation on the quadrature baseband transmission signal after the amplitude thereof has been limited by said amplitude maximum value limiting means. - View Dependent Claims (7, 8, 9, 10)
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Specification