WO2011058843A1 - Amplifier, distortion compensation circuit, and distortion compensation method - Google Patents

Amplifier, distortion compensation circuit, and distortion compensation method Download PDF

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Publication number
WO2011058843A1
WO2011058843A1 PCT/JP2010/068011 JP2010068011W WO2011058843A1 WO 2011058843 A1 WO2011058843 A1 WO 2011058843A1 JP 2010068011 W JP2010068011 W JP 2010068011W WO 2011058843 A1 WO2011058843 A1 WO 2011058843A1
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Prior art keywords
signal
frequency
distortion
frequency range
suppression
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PCT/JP2010/068011
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French (fr)
Japanese (ja)
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俊秀 桑原
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日本電気株式会社
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Publication of WO2011058843A1 publication Critical patent/WO2011058843A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits
    • H04B1/0475—Circuits with means for limiting noise, interference or distortion
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/32—Modifications of amplifiers to reduce non-linear distortion
    • H03F1/3241—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits
    • H03F1/3247—Modifications of amplifiers to reduce non-linear distortion using predistortion circuits using feedback acting on predistortion circuits
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
    • H03F1/34—Negative-feedback-circuit arrangements with or without positive feedback
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03F—AMPLIFIERS
    • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
    • H03F3/24—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers of transmitter output stages
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
    • H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
    • H04L27/36—Modulator circuits; Transmitter circuits
    • H04L27/366—Arrangements for compensating undesirable properties of the transmission path between the modulator and the demodulator
    • H04L27/367—Arrangements for compensating undesirable properties of the transmission path between the modulator and the demodulator using predistortion
    • H04L27/368—Arrangements for compensating undesirable properties of the transmission path between the modulator and the demodulator using predistortion adaptive predistortion
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits
    • H04B2001/0408—Circuits with power amplifiers
    • H04B2001/0433—Circuits with power amplifiers with linearisation using feedback

Definitions

  • the present invention relates to an amplification device, a distortion compensation circuit, and a distortion compensation method, and more particularly to an amplification device, a distortion compensation circuit, and a distortion compensation method that suppress distortion components included in an output signal of an amplifier.
  • FIG. 1a to 1d are diagrams relating to a technique for suppressing a nonlinear distortion component caused by nonlinearity of input / output characteristics of an amplifier.
  • FIG. 1a is a diagram illustrating an example of an amplitude characteristic 801 of a transmission signal input to an amplifier.
  • FIG. 1B is a diagram illustrating an amplitude characteristic 811 of the output signal of the amplifier when the transmission signal illustrated in FIG. 1A is amplified by an amplifier having nonlinearity in input / output characteristics.
  • FIGS. 1a and 1b when a transmission signal having the amplitude characteristic 801 shown in FIG. 1a is input to an amplifier having nonlinearity in input / output characteristics, an output signal 811 of the amplifier is shown in FIG.
  • the nonlinear distortion component 821 shown in 1b is generated.
  • the amplifier that suppresses the nonlinear distortion component can cancel the nonlinear distortion component generated in the amplified transmission signal by adding a suppression component for suppressing the nonlinear distortion component to the transmission signal before amplification, for example. That is, the amplifier that suppresses the nonlinear distortion component suppresses the generation of a component having the same amplitude and a phase difference of 180 degrees (or an even multiple of 180 degrees) after amplification of the transmission signal.
  • the nonlinear distortion component generated in the transmission signal after amplification is removed.
  • FIG. 1c is a diagram illustrating an example of an amplitude characteristic 802 of a transmission signal in which a suppression component is added to the transmission signal 801 illustrated in FIG. 1a.
  • FIG. 1d is a diagram showing the amplitude characteristic 812 of the output signal of the amplifier when the transmission signal 801 shown in FIG. 1c is amplified.
  • FIG. 2 is a block diagram showing a configuration example of an amplifying apparatus 700 that suppresses nonlinear distortion components caused by nonlinear characteristics of the amplifier.
  • the amplifying apparatus 700 performs modulation and frequency conversion processing on the transmission signal supplied from the input terminal 701, and amplifies the transmission signal subjected to the processing.
  • the amplification device 700 includes an amplitude calculation unit 710, a suppression coefficient extraction unit 720, a multiplication unit 730, a modulation unit 740, a D / A (Digital to Analog) conversion unit 750, a multiplication unit 760, and an amplification unit 770.
  • the directional coupler 780 and the frequency oscillation unit 790 are provided.
  • the amplifying apparatus 700 includes a multiplication unit 810, an A / D (Analog to Digital) conversion unit 820, a demodulation unit 830, a feedback signal holding unit 840, a transmission signal holding unit 850, and a suppression coefficient calculation.
  • Unit 860 and a suppression coefficient holding unit 870 are examples of the signals from the amplifying apparatus 700.
  • the transmission signal is supplied from the input terminal 701 to the amplitude calculation unit 710, the multiplication unit 730, and the transmission signal holding unit 850 via the signal line 709.
  • the transmission signal is a baseband signal in which information to be transmitted is expressed by a complex number.
  • the amplitude calculation unit 710 is an absolute value calculator that calculates the amplitude of a transmission signal expressed by a complex number.
  • the amplitude calculation unit 710 calculates the absolute value of a complex number representing the transmission signal as the amplitude of the transmission signal.
  • amplitude calculation section 710 squares the numerical values of the real part and imaginary part of the complex number representing the transmission signal, and calculates the square root of these sums as the amplitude of the transmission signal.
  • the amplitude calculation unit 710 supplies the calculated amplitude to the suppression coefficient extraction unit 720.
  • the suppression coefficient extraction unit 720 extracts, from the suppression coefficient holding unit 870, a suppression coefficient for suppressing a nonlinear distortion component caused by the nonlinear characteristics of the amplifier 770. Since this suppression coefficient has a characteristic for canceling the nonlinearity of the input / output characteristic of the amplifier 770, it changes according to the amplitude of the transmission signal. For this reason, the suppression coefficient extraction unit 720 extracts the suppression coefficient from the suppression coefficient holding unit 870 based on the amplitude magnitude from the amplitude calculation unit 710.
  • the suppression coefficient extraction unit 720 extracts a suppression coefficient corresponding to the magnitude of the amplitude from the amplitude calculation unit 710 out of the suppression coefficients held in the suppression coefficient holding unit 870. In addition, the suppression coefficient extraction unit 720 supplies the extracted suppression coefficient to the multiplication unit 730.
  • Multiplier 730 multiplies the transmission signal from input terminal 701 by the suppression coefficient from suppression coefficient extraction unit 720, thereby transmitting a suppression component for canceling the nonlinear distortion component due to the nonlinear characteristics of amplifier 770.
  • Complex multiplication means for superimposing on a signal.
  • Multiplier 730 outputs the multiplication result to modulator 740 as a distortion-suppressed transmission signal via signal line 739.
  • This distortion suppression transmission signal is a so-called predistortion signal. Note that a distortion-suppressed transmission signal can be generally called a distortion-suppressed input signal.
  • the modulation unit 740 performs modulation processing on the distortion-suppressed transmission signal from the multiplication unit 730. For example, the modulation unit 740 superimposes the distortion-suppressed transmission signal on a carrier wave signal having an intermediate frequency (Intermediate Frequency). Also, the modulation unit 740 supplies the carrier wave signal on which the distortion-suppressed transmission signal is superimposed to the D / A conversion unit 750 as a modulation signal.
  • the modulation unit 740 supplies the carrier wave signal on which the distortion-suppressed transmission signal is superimposed to the D / A conversion unit 750 as a modulation signal.
  • the D / A converter 750 converts the modulation signal, which is a digital signal, into an analog signal.
  • the D / A conversion unit 750 supplies the modulation signal converted into the analog signal to the multiplication unit 760 via the signal line 759.
  • Multiplier 760 converts the frequency of the modulated signal from D / A converter 750 to a frequency higher than that frequency.
  • the multiplier 760 converts the frequency of the modulated signal into an RF (Radio Frequency) band, for example, by multiplying the modulated signal by the oscillation signal from the frequency oscillating unit 790.
  • the multiplication unit 760 outputs the frequency-converted modulated signal to the amplification unit 770 as an RF signal via the signal line 769.
  • the amplifying unit 770 is an amplifying unit that amplifies the power of the input signal that is the RF signal from the multiplying unit 760.
  • the amplifying unit 770 has nonlinearity in power input / output characteristics.
  • the amplification unit 770 outputs the amplified RF signal to the directional coupler 780 as an output signal via the signal line 779.
  • the directional coupler 780 is a coupler that outputs the output signal from the amplifying unit 770 to the signal line 789 and outputs part of the power of the output signal to the multiplier 810 as a feedback signal via the signal line 788. is there.
  • This feedback signal is a signal in which the power of the RF signal is attenuated.
  • Multiplication unit 810 an oscillation signal from the frequency oscillation unit 790, a feedback signal from the directional coupler 780, the multiplication of, for converting the frequency of the feedback signal to an intermediate frequency.
  • Multiplier 810 outputs the frequency-converted feedback signal to A / D converter 820 via signal line 819.
  • the A / D conversion unit 820 converts the feedback signal that is an analog signal from the multiplication unit 810 into a digital signal.
  • the A / D conversion unit 820 supplies the feedback signal converted into the digital signal to the demodulation unit 830.
  • the demodulation unit 830 performs a demodulation process corresponding to the modulation process of the modulation unit 740 on the feedback signal from the A / D conversion unit 820.
  • the demodulating unit 830 holds the demodulated feedback signal in the feedback signal holding unit 840 via the signal line 839.
  • the feedback signal holding unit 840 is a memory that holds the feedback signal from the demodulation unit 830.
  • the transmission signal holding unit 850 is a memory that holds a transmission signal supplied from the input terminal 701.
  • the feedback signal held in the feedback signal holding unit 840 is a signal obtained by amplifying the transmission signal held in the transmission signal holding unit 850 by the amplification unit 770.
  • the suppression coefficient calculation unit 860 calculates a suppression coefficient for multiplying the transmission signal from the input terminal 701.
  • the suppression coefficient calculation unit 860 refers to the feedback signal holding unit 840 and the transmission signal holding unit 850, and based on the transmission signal and the feedback signal corresponding to the transmission signal, the suppression coefficient according to the nonlinear characteristic of the amplification unit 770 to calculate the coefficient.
  • the suppression coefficient calculation unit 860 calculates the suppression coefficient so that, for example, the magnitude of the error signal that is the difference between the transmission signal and the feedback signal is minimized.
  • the control coefficient calculation unit 860 is realized by, for example, a central processing unit (DSP: Digital Signal Processor).
  • the suppression coefficient calculation unit 860 holds the calculated suppression coefficient in the suppression coefficient holding unit 870. In addition, every time the suppression coefficient is calculated, the suppression coefficient calculation unit 860 holds (overwrites) the suppression coefficient in the suppression coefficient holding unit 870 so as to overlap the area to be held.
  • the suppression coefficient holding unit 870 is a memory that holds the suppression coefficient calculated by the suppression coefficient calculation unit 860.
  • the suppression coefficient holding unit 870 is realized by, for example, a lookup table.
  • 3A to 3G are diagrams illustrating the amplitude characteristics of signals output to the signal lines in the amplification device 700.
  • FIG. 3 a shows the amplitude characteristic 702 of the transmission signal supplied from the input terminal 701 via the signal line 709.
  • the amplitude characteristic 702 indicates a waveform with a center frequency of the transmission signal of “0 Hz” and a frequency bandwidth BW. Since this transmission signal is represented by a complex number, it can take a negative frequency.
  • FIG. 3 b shows the amplitude characteristic 731 of the distortion-suppressed transmission signal output from the multiplier 730 via the signal line 739.
  • a suppression component 732 generated by multiplying the transmission signal by the suppression coefficient from the suppression coefficient extraction unit 720 is superimposed on the amplitude characteristic 731.
  • FIG. 3 c shows an amplitude characteristic 751 of the modulation signal output from the D / A conversion unit 750 via the signal line 759.
  • the center frequency of the amplitude characteristic 751 is subjected to modulation processing by the modulation unit 740, and thus indicates an intermediate frequency f_if.
  • FIG. 3d shows the amplitude characteristic 761 of the RF signal output from the multiplier 760 via the signal line 769. Since the center frequency of the amplitude characteristic 761 is frequency-converted by the multiplier 760, it indicates the RF frequency f_rf.
  • FIG. 3 e shows an amplitude characteristic 771 of the RF signal output from the amplifying unit 770 via the signal line 779.
  • the amplitude characteristic 771 shows the amplitude characteristic from which the nonlinear distortion component is removed because the suppression component 762 shown in FIG. 3d cancels the nonlinear distortion component caused by the nonlinear characteristic of the amplification unit 770.
  • FIG. 3 f shows the amplitude characteristic 811 of the feedback signal output from the multiplier 810 via the signal line 819. Since the center frequency of the amplitude characteristic 881 is frequency-converted by the multiplier 760, it indicates the intermediate frequency f_if.
  • FIG. 3g shows the amplitude characteristic 831 of the feedback signal output from the demodulator 830 via the signal line 839.
  • the center frequency of the amplitude characteristic 831 indicates “0 Hz” because the demodulation processing is performed by the demodulation unit 830.
  • This feedback signal is a baseband signal.
  • the amplifying apparatus 700 suppresses the nonlinear distortion component caused by the nonlinear characteristic of the amplifying unit 770 by multiplying the transmission signal by the suppression coefficient from the suppression coefficient extracting unit 720 in the multiplying unit 730.
  • the frequency characteristic of the nonlinear distortion component changes depending on the frequency characteristic of the amplifying unit. For this reason, there is a problem in that a part of the distortion component remains in the output signal of the amplification unit only by adding the suppression component to the transmission signal.
  • the change in the frequency characteristic of the nonlinear distortion component becomes significant, and the output signal of the amplifying unit remaining distortion component is increased.
  • FIG. 4a to 4d are diagrams relating to frequency fluctuations of nonlinear distortion components caused by the frequency characteristics of the amplification unit.
  • the transmission signal having the amplitude characteristic 801 shown in FIG. 4a is input to an amplification unit having nonlinearity in input / output characteristics and having frequency characteristics
  • the output signal of the amplification unit is shown in FIG. 4b.
  • the distortion component 832 shown is generated due to the influence of the frequency characteristic of the amplification unit.
  • the nonlinear distortion component 832 exhibits an asymmetric amplitude characteristic due to the frequency characteristic of the amplifying unit is referred to as a memory effect here.
  • Patent Document 1 A technique for solving such a problem is described in Patent Document 1.
  • Distortion compensating apparatus the complex digital filter, by correcting the amplitude characteristic in the analog circuit unit including a power amplifier, suppressing the distortion component included in the output signal of the power amplifier.
  • the adaptive equalizer selects a filter coefficient to be set in the complex digital filter from among a plurality of filter coefficients based on a feedback signal from the power amplifier. Therefore, there is a problem that the circuit scale increases.
  • An object of the present invention is to provide an amplifier, a distortion compensation circuit, and a distortion compensation method that solve the above-described problems.
  • the distortion compensation circuit of the present invention includes an input terminal that receives an input signal for generating an amplification target signal supplied to an amplification unit that amplifies power, and the amplification caused by nonlinearity of input / output characteristics of the amplification unit Multiplication means for generating a distortion suppression input signal by multiplying the input signal by a suppression coefficient for suppressing a distortion component of the output signal of the means, and a frequency component of a difference signal between the input signal and the distortion suppression input signal extracting means for extracting a frequency component as an extraction signal for each of said frequency ranges corresponding to each of a plurality of frequency ranges of, for correcting the change in the frequency characteristic of the distortion components due to the frequency characteristic possessed by the amplifying means
  • Correction coefficient holding means for holding the correction coefficient for each frequency range, and multiplying the extracted signal by the correction coefficient for each frequency range.
  • a correction signal generating means for generating a correction signal for each of the frequency ranges Te, on the basis of the correction signal and the distortion suppression input signal for each frequency
  • An amplifying apparatus is an amplifying apparatus that amplifies an input signal by having an amplifying unit having nonlinearity in power input / output characteristics and having frequency characteristics, and is caused by the nonlinearity of the amplifying means.
  • Multiplying means for generating a distortion suppression input signal by multiplying the input signal with a suppression coefficient for suppressing a distortion component of the output signal of the amplification means, the input signal and the distortion suppression input signal
  • Extraction means for extracting a frequency component corresponding to each of a plurality of frequency ranges among the frequency components of the difference signal as an extraction signal for each frequency range, and frequency characteristics of the distortion component due to the frequency characteristics of the amplification means
  • Correction coefficient holding means for holding a correction coefficient for correcting a change in each frequency range, and multiplying the extracted signal by the correction coefficient for each frequency range.
  • a correction signal generating means for generating a correction signal for each of the frequency range by a correction signal for each of the frequency ranges, and the distortion suppression input signal, based on the amplified signal generating means for generating an amplified signal,
  • the amplification means amplifies the amplification target signal.
  • the distortion compensation method of the present invention includes: an input terminal that receives an input signal for generating an amplification target signal supplied to an amplification unit that amplifies power; and the amplification caused by nonlinearity of input / output characteristics of the amplification unit A plurality of suppression coefficient holding means for holding a suppression coefficient for suppressing a distortion component of the output signal of the means, and a plurality of correction coefficients for correcting a change in the frequency characteristic of the distortion component caused by the frequency characteristic of the amplification means.
  • the amplitude characteristic of the distortion suppression transmission signal output from the multiplication part 730 is shown.
  • the amplitude characteristic of the modulation signal output from the D / A conversion unit 750 is shown.
  • the amplitude characteristic of the RF signal output from the multiplier 760 is shown.
  • the amplitude characteristic of the RF signal output from the amplification unit 770 is shown.
  • the amplitude characteristic of the feedback signal output from the multiplier 810 is shown.
  • the amplitude characteristic of the feedback signal output from the demodulator 830 is shown. It is a figure which shows the amplitude characteristic of the transmission signal input into the amplifier which has nonlinearity in an input-output characteristic, and has a frequency characteristic.
  • FIG. 4B is a diagram illustrating amplitude characteristics of an output signal of an amplifier when the transmission signal illustrated in FIG. 4A is amplified. It is a figure which shows the amplitude characteristic of the transmission signal with which the suppression component was superimposed. It is a figure which shows the example in which a part of nonlinear distortion component of the output signal of an amplifier remains. It is a block diagram which shows the amplification apparatus in embodiment of this invention. 3 is a block diagram illustrating an example of a configuration of a frequency characteristic correction unit 300.
  • FIG. It is a figure which shows an example of the amplitude characteristic of the low-pass filter 351. It is a figure which shows an example of the amplitude characteristic of the low-pass filter 352.
  • FIG. 6 is a diagram illustrating amplitude characteristics of a transmission signal input to a frequency characteristic correction unit 300.
  • FIG. 6 is a diagram illustrating amplitude characteristics of a distortion-suppressed transmission signal input to a frequency characteristic correction unit 300.
  • FIG. The amplitude characteristic of the output signal in which the low frequency side of the nonlinear distortion component is low and the high frequency side is high is shown.
  • the amplitude characteristic of the output signal in which the low frequency side of the nonlinear distortion component is high and the high frequency side is low is shown.
  • the amplitude characteristic of the output signal in which the low frequency side and the high frequency side of the nonlinear distortion component are increased is shown.
  • the amplitude characteristic of the output signal in which the low frequency side and the high frequency side of the nonlinear distortion component are low is shown.
  • 5 is a flowchart illustrating an example of a processing procedure of a distortion compensation method in the amplification device 100.
  • FIG. 5 is a block diagram illustrating an amplifying apparatus according to an embodiment of the present invention.
  • the amplifying apparatus 100 performs modulation and frequency conversion processing on the transmission signal from the input terminal 101, and amplifies the transmission signal subjected to the processing.
  • the transmission signal from the input terminal 101 is a baseband signal in which information to be transmitted is expressed by a complex number.
  • a transmission signal can generally be referred to as an input signal.
  • the amplification device 100 includes a modulation unit 110, a D / A conversion unit 120, a multiplication unit 130, an amplification unit 140, a directional coupler 150, a frequency oscillation unit 160, a multiplication unit 170, and an A / D conversion.
  • Unit 180, demodulator 190, and distortion compensation circuit 200 includes an amplitude calculation unit 210, a suppression coefficient extraction unit 220, a multiplication unit 230, a feedback signal holding unit 240, a transmission signal holding unit 250, a suppression coefficient calculation unit 260, and a suppression coefficient holding. It includes a section 270, a.
  • the distortion compensation circuit 200 includes a frequency characteristic correction unit 300, a correction coefficient setting unit 310, and a correction coefficient holding unit 320.
  • the modulation unit 110, the D / A conversion unit 120, the multiplication unit 130, the amplification unit 140, and the directional coupler 150 are the modulation unit 740, the D / A conversion unit 750, the multiplication unit 760, the amplification unit 770, and the direction, respectively. a sexual coupler 780 of the same configuration.
  • Amplifying section 140 can generally be referred to as an amplifying means.
  • the frequency oscillation unit 160, the multiplication unit 170, the A / D conversion unit 180, and the demodulation unit 190 have the same configuration as the frequency oscillation unit 790, the multiplication unit 810, the A / D conversion unit 820, and the demodulation unit 830, respectively.
  • the amplitude calculation unit 210, the suppression coefficient extraction unit 220, and the multiplication unit 230 have the same configuration as the amplitude calculation unit 710, the suppression coefficient extraction unit 720, and the multiplication unit 730, respectively.
  • Multiplier 230 can be generally referred to as multiplication means.
  • the feedback signal holding unit 240, the transmission signal holding unit 250, the suppression coefficient calculation unit 260, and the suppression coefficient holding unit 270 are respectively a feedback signal holding unit 840, a transmission signal holding unit 850, a suppression coefficient calculation unit 860, and a suppression coefficient holding. part 870 is the same as the configuration.
  • the frequency characteristic correcting portion 300 for other configurations other than the correction coefficient setting unit 310 and the correction coefficient holding unit 320, because it is similar to the configuration shown in FIG. 2, the description herein.
  • the correction coefficient setting unit 310 causes the correction coefficient holding unit 320 to hold a correction coefficient for correcting the frequency characteristics of the distortion-suppressed transmission signal from the multiplication unit 230.
  • the correction coefficient setting unit 310 receives an operation related to the setting of the correction coefficient by the user of the amplification device 100. At this time, the user of the amplifying apparatus 100 sequentially changes the value of the correction coefficient, measures the spectrum of the output signal of the amplifying unit 140, and determines the value that minimizes the distortion component of the output signal as the correction coefficient setting unit 310. It performs an operation to input to. The correction coefficient setting unit 310 sets the correction coefficient value in the correction coefficient holding unit 320 based on the accepted operation.
  • the correction coefficient holding unit 320 is a memory that holds the correction coefficient set by the correction coefficient setting unit 310. That is, the correction coefficient holding unit 320 holds a correction coefficient for correcting a change in the frequency characteristic of the nonlinear distortion component caused by the frequency characteristic of the amplification unit 140. This correction coefficient is expressed by a complex number. Further, the correction coefficient holding unit 320 outputs the correction coefficient to the frequency characteristic correction unit 300 via the signal line 329.
  • the correction coefficient holding unit 320 can be generally called correction coefficient holding means.
  • the frequency characteristic correction unit 300 corrects the frequency characteristic of the distortion-suppressed transmission signal in order to reduce the fluctuation of the frequency characteristic of the nonlinear distortion component caused by the frequency characteristic of the amplification unit 140. That is, the frequency characteristic correction unit 300 is a memory effect cancellation circuit that adds a specific frequency characteristic to the distortion-suppressed transmission signal in order to cancel out the fluctuation of the frequency characteristic of the nonlinear distortion component caused by the memory effect of the amplification unit 140.
  • the frequency characteristic correction unit 300 corrects the frequency characteristic of the distortion-suppressed transmission signal based on the transmission signal from the input terminal 101 and the correction coefficient held in the correction coefficient holding unit 320. Further, the frequency characteristic correction unit 300 outputs the corrected distortion-suppressed transmission signal to the modulation unit 110 via the signal line 309.
  • the amplifying apparatus 100 may be configured by only the amplifying unit 140, the multiplying unit 230, the frequency characteristic correcting unit 300, and the correction coefficient holding unit 320. Further, the distortion compensation circuit 200 may be configured by only the multiplication unit 230, the frequency characteristic correction unit 300, and the correction coefficient holding unit 320.
  • FIG. 6 is a block diagram illustrating a configuration example of the frequency characteristic correction unit 300.
  • the frequency characteristic correction unit 300 includes an extraction unit 350, a multiplication unit 360, and an addition unit 370.
  • the extraction unit 350 includes an adder 340, a low-pass filter 351, and a high-pass filter 352.
  • Multiplier 360 includes multipliers 361 and 362.
  • the low-frequency and high-frequency correction coefficients are held in the correction coefficient holding unit 320, respectively, and the low-frequency is supplied to the multipliers 361 and 362 via the signal lines 327 and 328 included in the signal line 329, respectively.
  • a high-frequency correction factor is assumed to be supplied.
  • Extraction unit 350 a transmission signal from the signal line 109, among the frequency components of the distortion suppression transmission signals and, of the differential signal from the signal line 239, a frequency component corresponding to each of a plurality of frequency ranges for each frequency range each extraction.
  • Extracting unit 350 among the frequency components of the difference signal between the transmission signal and the distortion suppression transmission signal, and extracts each signal consisting of frequency components of negative frequency range, a signal composed of the frequency components of the positive frequency range, the . That is, the extraction unit 350 corresponds to a frequency range lower than the middle of the entire frequency range of the difference signal and other frequency ranges among the frequency components of the difference signal between the transmission signal and the distortion suppression transmission signal. extracting a frequency component for each frequency range.
  • the extraction unit 350 supplies the extracted signal to the multiplication unit 360 as an extraction signal.
  • Extraction unit 350 can generally be referred to as extraction means.
  • the adder 340 extracts a suppression component included in the distortion suppression transmission signal by calculating a difference between the transmission signal from the signal line 109 and the distortion suppression transmission signal from the signal line 239.
  • the suppression component referred to here is a component for canceling the nonlinear distortion component caused by the nonlinear characteristic of the amplification unit 140, and is a component generated by multiplication of the transmission signal and the suppression coefficient in the multiplication unit 230.
  • the adder 340 outputs the calculation result as a difference signal to the low-pass filter 351 and the high-pass filter 352.
  • the low-pass filter 351 and the high-pass filter 352 are filters for dividing a suppression component that is a differential signal into a low-frequency range and a high-frequency range.
  • the low-pass filter 351 and the high-pass filter 352 are realized by a digital filter such as a FIR (Finite Impulse Response) filter, for example.
  • FIR Finite Impulse Response
  • the low-pass filter 351 is a filter that extracts a low-frequency component that is lower than the center frequency of the difference signal from the frequency components of the difference signal from the adder 340. That is, the low-pass filter 351 extracts a low-frequency component from the suppression components. Further, the low-pass filter 351 outputs the extracted low-frequency component to the multiplier 361 as a low-frequency extraction signal.
  • the high-pass filter 352 is a filter that extracts a high-frequency component higher than the center frequency of the difference signal from the frequency components of the difference signal from the adder 340. That is, the high-pass filter 352 extracts a high-frequency component from the suppression components. The high-pass filter 352 outputs the extracted high-frequency component to the multiplier 362 as a high-frequency extraction signal.
  • the multiplication unit 360 is a complex multiplier that multiplies the extracted signal for each frequency range by a correction coefficient corresponding to the frequency range in order to give a specific frequency characteristic to the suppression component included in the distortion suppression transmission signal. That is, the multiplication unit 360, by multiplying each frequency range extraction signal from the extraction unit 350 the correction coefficients held in correction coefficient holding unit 320, it generates a correction signal for each frequency range. The multiplication unit 360 supplies the generated correction signals to the addition unit 370. Multiplier 360 can generally be referred to as a correction signal generating means.
  • the multiplier 361 emphasizes or suppresses the low frequency component of the suppression component in the distortion suppression transmission signal according to the low frequency correction coefficient from the signal line 327.
  • the multiplier 361 generates a low-frequency correction signal by multiplying the low-frequency correction coefficient from the signal line 327 by the low-frequency extraction signal from the low-pass filter 351.
  • the multiplier 361 supplies the low-frequency correction signal to the adding unit 370.
  • Multiplier 362 emphasizes or suppresses the high frequency component of the suppression component in the distortion suppression transmission signal in accordance with the high frequency correction coefficient from signal line 328.
  • the multiplier 362 multiplies the high-frequency extracted signal from the high-pass filter 352 by the high-frequency correction coefficient from the signal line 328 to generate a high-frequency correction signal.
  • the multiplier 362 supplies the high-frequency correction signal to the adder 370.
  • the addition unit 370 gives a specific frequency characteristic to the suppression component by adding the correction signal in each frequency range to the distortion suppression transmission signal.
  • Adder 370 generates a new distortion-suppressed transmission signal based on the correction signal corresponding to each of the plurality of frequency ranges and the distortion-suppressed transmission signal from signal line 239. Note that a new distortion-suppressed transmission signal can be generally called an amplification target signal.
  • the adding unit 370 adds the low-frequency correction signal from the multiplier 361, the high-frequency correction signal from the multiplier 362, and the distortion suppression transmission signal from the signal line 239. generates a new distortion suppression transmission signals. That is, the adding unit 370 adds a correction signal corresponding to each of the low frequency range and the other frequency range and a distortion suppression transmission signal obtained by multiplying the transmission signal by a suppression coefficient, thereby generating a new distortion suppression transmission. to generate a signal. In addition, the adding unit 370 supplies the new distortion-suppressed transmission signal to the modulation unit 110 via the signal line 309. Adder 370 can be generally referred to as amplification target signal generation means.
  • the adding unit 370 generates a new distortion suppression transmission signal based on the correction signal for each frequency range and the distortion suppression transmission signal from the signal line 239.
  • the unit 370 may generate a new distortion-suppressed transmission signal based on the correction signal for each frequency range and the transmission signal from the signal line 109.
  • the frequency characteristic correction unit 300 corrects the frequency characteristic of the distortion suppression transmission signal based on the suppression component included in the distortion suppression transmission signal from the multiplication unit 230.
  • the correction unit 300 may correct the frequency characteristics of the distortion-suppressed transmission signal using the low-frequency component and the high-frequency component of the distortion-suppressed transmission signal from the multiplication unit 230.
  • FIG. 7a and 7b are diagrams showing examples of amplitude characteristics of the low-pass filter 351 and the low-pass filter 352.
  • Fs indicates the sampling frequency of the transmission signal.
  • FIG. 7 a is a diagram showing the amplitude characteristics of the low-pass filter 351.
  • This amplitude characteristic has a large amplitude gain in the low frequency range from the vicinity of the center frequency “0 Hz” of the differential signal to the vicinity of “ ⁇ fs / 2”.
  • the differential signal after passing through the low-pass filter 351 is a signal composed of frequency components in the low-frequency range among the frequency components of the differential signal.
  • this amplitude characteristic has a relatively low amplitude gain in the vicinity of “0 Hz”. This is because the non-linear distortion component has a small amplitude fluctuation in the vicinity of the center frequency.
  • FIG. 7 b is a diagram showing the amplitude characteristics of the high-pass filter 352.
  • This amplitude characteristic has a large amplitude gain in the high frequency range from the vicinity of the center frequency “0 Hz” of the difference signal to the vicinity of “fs / 2”.
  • the differential signal after passing through the high-pass filter 352 is a signal composed of frequency components in the high-frequency range among the frequency components of the differential signal.
  • this amplitude characteristic has a relatively low amplitude gain in the vicinity of “0 Hz”. This is because the amplitude fluctuation is small in the vicinity of the center frequency of the nonlinear distortion component.
  • the frequency characteristic of the nonlinear distortion component can be appropriately corrected.
  • FIG. 8a and 8b are diagrams illustrating an example of amplitude characteristics of a transmission signal and a distortion-suppressed transmission signal supplied to the frequency characteristic correction unit 300.
  • FIG. 8 a shows the amplitude characteristic 102 of the transmission signal supplied from the input terminal 101 via the signal line 109.
  • the amplitude characteristic 102 of the transmission signal indicates a waveform having a center frequency of “0 Hz” and a frequency bandwidth BW.
  • FIG. 8 b shows the amplitude characteristic 131 of the distortion-suppressed transmission signal output from the multiplier 230 via the signal line 239.
  • the amplitude characteristic 131 includes a suppression component 132 generated by multiplying the transmission signal by the suppression coefficient from the suppression coefficient extraction unit 220.
  • FIGS. 8a and 8b show examples of amplitude characteristics of the output signal of the frequency characteristic correction unit 300 when the transmission signal 102 and the distortion suppression transmission signal 131 shown in FIGS. 8a and 8b are supplied to the frequency characteristic correction unit 300.
  • FIG. FIG. In this example, a representative example of four cases among combinations of a low-frequency correction coefficient and a high-frequency correction coefficient will be briefly described.
  • FIG. 9 a shows the amplitude characteristic 301 of the output signal when the low frequency side of the nonlinear distortion component is low and the high frequency side is high due to the frequency characteristic of the amplification unit 140.
  • the suppression component 371 in the amplitude characteristic 301 is suppressed on the low frequency side and emphasized on the high frequency side compared to the suppression component 132 generated by the multiplication unit 230.
  • the correction coefficient holding unit 320 holds a negative low-frequency correction coefficient and a positive high-frequency correction coefficient.
  • FIG. 9 b shows the amplitude characteristic 302 of the output signal when the low frequency side of the nonlinear distortion component is high and the high frequency side is low due to the frequency characteristic of the amplification unit 140.
  • the suppression component 372 in the amplitude characteristic 302 is emphasized on the low frequency side and suppressed on the high frequency side compared to the suppression component 132.
  • the correction coefficient holding unit 320 holds a positive low-frequency correction coefficient and a negative high-frequency correction coefficient.
  • FIG. 9c shows the amplitude characteristic 303 of the output signal when the low frequency side and the high frequency side of the nonlinear distortion component are increased by the frequency characteristic of the amplification unit 140.
  • the suppression component 373 in the amplitude characteristic 303 is emphasized on the low frequency side and the high frequency side compared to the suppression component 132 generated by the multiplication unit 230.
  • the correction coefficient holding unit 320 holds a positive low-frequency correction coefficient and a positive high-frequency correction coefficient.
  • FIG. 9d shows the amplitude characteristic 304 of the output signal when the low frequency side and the high frequency side of the nonlinear distortion component are lowered by the frequency characteristic of the amplification unit 140.
  • the suppression component 374 in the amplitude characteristic 304 is suppressed on the low frequency side and the high frequency side compared to the suppression component 132.
  • the correction coefficient holding unit 320 holds a negative low-frequency correction coefficient and a negative high-frequency correction coefficient.
  • the correction coefficient setting unit 310 in accordance with the frequency characteristic of the amplification section 140, by setting the low-range correction coefficient and high correction coefficients respectively, amplifier 100 controls the frequency characteristic of inhibiting component 132 can do.
  • FIG. 10 is a flowchart illustrating an example of a processing procedure of a distortion compensation method in the amplification device 100.
  • the suppression coefficient extracting unit 220 based on the magnitude of the amplitude of the transmission signal from the amplitude calculating unit 210, extracts the suppression coefficient held in the suppression coefficient holding unit 270 (step S901).
  • multiplier 230 a transmission signal from the input terminal 101, a suppression coefficient extracted by suppression factor extraction unit 220, on the basis, to generate a distortion suppression transmission signal (step S902).
  • the adder 340 generates a differential signal composed of suppression components by subtracting the transmission signal from the distortion suppression transmission signal that is the output of the multiplication unit 230 (step S903).
  • the low-pass filter 351 extracts a low-frequency component in the difference signal from the adder 340 and outputs the extracted signal as a low-frequency extraction signal.
  • the high-pass filter 352 extracts a high-frequency component from the difference signal from the adder 340 and outputs the extracted signal as a high-frequency extraction signal (step S904).
  • the multiplier 361 based on the extracted signal of low frequency from the low-pass filter, and the correction coefficient of low frequency held in the correction coefficient storing unit 320, generates a correction signal of low frequency.
  • the multiplier 362 generates a high-frequency correction signal based on the high-frequency extracted signal from the high-pass filter and the high-frequency correction coefficient held in the correction coefficient holding unit 320 (step). S905).
  • Adder 370 then generates a new distortion-suppressed transmission signal by adding the low-frequency and high-frequency correction signals from multipliers 361 and 362 to the distortion-suppressed transmission signal (step S906). processing procedure of compensation method ends.
  • the frequency characteristic correcting unit 300 can correct the frequency characteristic of inhibiting component in the distortion suppressing transmission signal based on the correction coefficient set by the correction coefficient setting unit 310.
  • the distortion compensation circuit 200 can reduce the nonlinear distortion component included in the output signal of the amplification unit 140. That is, the frequency characteristic correction unit 300 can suppress distortion components due to the memory effect of the amplification unit 140.
  • the extraction unit 350 extracts, for each frequency range, frequency components corresponding to each of a plurality of frequency ranges from among the frequency components of the difference signal between the transmission signal and the distortion-suppressed transmission signal. Then, the multiplication unit 360 generates a correction signal for each frequency range based on the correction coefficient from the correction coefficient holding unit 320 and the extraction signal from the extraction unit 350 for each frequency range. Thereby, the frequency characteristic of the suppression component in a distortion suppression transmission signal can be controlled for every frequency range.
  • the frequency characteristic correction unit 300 uses the low-pass filter 351, the high-pass filter 352, and the multipliers 361 and 362 to independently reduce the low-frequency and high-frequency characteristics in the suppression component. Control. Thus alone control only two bands, since the frequency variation of the nonlinear distortion component caused by the memory effect is not steep, it is possible to remove residual components at the output of the amplifier 140 adequately. Thereby, the distortion compensation circuit 200 can correct the frequency characteristic of the suppression component with the minimum number of filters, and thus the circuit scale of the distortion compensation circuit 200 can be suppressed.
  • the user of the amplifying apparatus 100 can control the frequency characteristics of the suppression component included in the distortion-suppressed transmission signal only by adjusting the two correction coefficients. Therefore, by providing a digital filter instead of the frequency characteristic correcting unit 300, as compared with the case of setting the number of filter coefficients directly, the user can conveniently control the frequency characteristic of inhibiting component.
  • the distortion compensation circuit 200 controls the frequency characteristic of the suppression component with high accuracy by reducing the setting step width of the correction coefficient as compared with the case where a predetermined frequency characteristic is selected and set in the digital filter. be able to.
  • the frequency characteristic correcting unit 300 can generate a correction signal based on the suppression component by causing the adder 340 to generate a differential signal between the transmission signal and the distortion suppression transmission signal.
  • the frequency characteristic correction unit 300 can appropriately suppress the frequency fluctuation of the nonlinear distortion component in which the degree of influence of the frequency characteristic of the amplification unit 140 changes according to the magnitude of the nonlinear distortion component. That is, the frequency characteristic correcting unit 300 can more appropriately reduce the distortion component included in the output signal of the amplifying unit 140 as compared with the case where the frequency characteristic is corrected based on the distortion suppression transmission signal from the multiplying unit 230. it can.
  • the amplitude characteristic near the center frequency of the difference signal in the low-pass filter 351 and the high-pass filter 352. Is kept low. For this reason, it is possible to increase the correction amount of the amplitude of the frequency band in the middle of the frequency range of the low-pass filter 351 or the high-pass filter 352 as compared with the vicinity of the center frequency of the suppression component with small frequency fluctuation. Thereby, even if it is the structure of only two filters, the distortion component resulting from the frequency characteristic which the amplifier 140 has can be suppressed appropriately.
  • the amplifying apparatus 100 sets the correction coefficient in the correction coefficient holding unit 320 based on the operation of the user.
  • the amplifying apparatus 100 is based on the transmission signal and the feedback signal.
  • a correction coefficient may be generated.
  • the illustrated configuration is merely an example, and the present invention is not limited to the configuration.

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Abstract

Provided is a distortion compensation circuit for reducing a distortion component of an output signal from an amplifier, and reducing circuit scale. The distortion compensation circuit includes: a multiplication unit which calculates a distortion suppression input signal in accordance with an input signal and a suppression coefficient for suppressing the distortion component originating in the nonlinear characteristics of the amplifier; an extraction unit which extracts, as an extraction signal for each frequency range, a frequency component corresponding to each of a plurality of frequency ranges from among the frequency components of a differential signal of the input signal and the distortion suppression input signal; a compensation coefficient holder for holding, for each frequency range, a compensation coefficient for correcting change in the frequency characteristics of the distortion component originating in the frequency characteristics of the amplifier; a multiplication unit which multiplies, for each frequency range, the compensation coefficient by the extraction signal to generate a compensation signal; and an addition unit which generates a signal to be amplified in accordance with the input signal and the compensation signal of each frequency range.

Description

増幅装置、歪み補償回路および歪み補償方法Amplifying device, distortion compensation circuit, and distortion compensation method
　本発明は、増幅装置、歪み補償回路および歪み補償方法に関し、特に増幅器の出力信号に含まれる歪み成分を抑制する増幅装置、歪み補償回路および歪み補償方法に関する。 The present invention relates to an amplification device, a distortion compensation circuit, and a distortion compensation method, and more particularly to an amplification device, a distortion compensation circuit, and a distortion compensation method that suppress distortion components included in an output signal of an amplifier.
　近年の高速無線伝送システムにおいては、Ｗ－ＣＤＭＡ（Wideband　Code　Division　Multiple　Access：広帯域符号分割多元接続）、ＷｉＭＡＸ（Worldwide　Interoperability　for　Microwave　Access）などの通信方式が用いられている。これらの通信方式により生成される送信信号は増幅器の飽和領域付近において増幅されることが多い。このため、増幅器の有する入出力特性の非線形性によって、増幅後の送信信号には、歪み成分が生じてしまう。このような歪み成分を以下、非線形歪み成分という。 In recent high-speed wireless transmission systems, communication methods such as W-CDMA (Wideband Code Division Multiple Access) and WiMAX (Worldwide Interoperability for Microwave Access) are used. In many cases, transmission signals generated by these communication methods are amplified near the saturation region of the amplifier. For this reason, distortion components occur in the amplified transmission signal due to nonlinearity of the input / output characteristics of the amplifier. Such a distortion component is hereinafter referred to as a nonlinear distortion component.
　図１ａ～図１ｄは、増幅器の有する入出力特性の非線形性に起因する非線形歪み成分の抑制手法に関する図である。図１ａは、増幅器に入力される送信信号の振幅特性８０１の一例を示す図である。図１ｂは、入出力特性に非線形性を有する増幅器によって、図１ａに示された送信信号が増幅された場合における増幅器の出力信号の振幅特性８１１を示す図である。 1a to 1d are diagrams relating to a technique for suppressing a nonlinear distortion component caused by nonlinearity of input / output characteristics of an amplifier. FIG. 1a is a diagram illustrating an example of an amplitude characteristic 801 of a transmission signal input to an amplifier. FIG. 1B is a diagram illustrating an amplitude characteristic 811 of the output signal of the amplifier when the transmission signal illustrated in FIG. 1A is amplified by an amplifier having nonlinearity in input / output characteristics.
　図１ａおよび図１ｂに示すように、入出力特性に非線形性を有する増幅器に対し、図１ａに示された振幅特性８０１の送信信号が入力されると、その増幅器の出力信号８１１には、図１ｂに示された非線形歪み成分８２１が生じる。 As shown in FIGS. 1a and 1b, when a transmission signal having the amplitude characteristic 801 shown in FIG. 1a is input to an amplifier having nonlinearity in input / output characteristics, an output signal 811 of the amplifier is shown in FIG. The nonlinear distortion component 821 shown in 1b is generated.
　これに対し、増幅器における非線形性を有する入出力特性（以下、非線形特性と称す）に起因する非線形歪み成分を抑制する増幅器がある。非線形歪み成分を抑制する増幅器は、例えば、非線形歪み成分を抑制するための抑制成分を増幅前の送信信号に付加することによって、増幅後の送信信号に生じる非線形歪み成分を相殺することができる。すなわち、非線形歪み成分を抑制する増幅器は、非線形歪み成分に対して、振幅が同一であり、位相が１８０度（または１８０度の偶数倍）異なる成分を送信信号の増幅後に生成するために、抑制成分を増幅前の送信信号に予め付加することによって、増幅後の送信信号に生じる非線形歪み成分を除去する。 On the other hand, there is an amplifier that suppresses nonlinear distortion components caused by input / output characteristics having nonlinearity in the amplifier (hereinafter referred to as nonlinear characteristics). The amplifier that suppresses the nonlinear distortion component can cancel the nonlinear distortion component generated in the amplified transmission signal by adding a suppression component for suppressing the nonlinear distortion component to the transmission signal before amplification, for example. That is, the amplifier that suppresses the nonlinear distortion component suppresses the generation of a component having the same amplitude and a phase difference of 180 degrees (or an even multiple of 180 degrees) after amplification of the transmission signal. By adding the component in advance to the transmission signal before amplification, the nonlinear distortion component generated in the transmission signal after amplification is removed.
　図１ｃは、図１ａに示された送信信号８０１に抑制成分が付加された送信信号の振幅特性８０２の一例を示す図である。図１ｄは、図１ｃに示された送信信号８０１が増幅された場合における増幅器の出力信号の振幅特性８１２を示す図である。 FIG. 1c is a diagram illustrating an example of an amplitude characteristic 802 of a transmission signal in which a suppression component is added to the transmission signal 801 illustrated in FIG. 1a. FIG. 1d is a diagram showing the amplitude characteristic 812 of the output signal of the amplifier when the transmission signal 801 shown in FIG. 1c is amplified.
　このように、送信信号８０１に抑制成分８２２が重畳された送信信号８０２を増幅すると、増幅器の非線形性に起因する非線形歪み成分８２１が抑制成分８２２によって相殺されるため、本来の送信信号のみが増幅された信号８１２が出力される。ここで、このような処理を行う増幅装置の構成例について図面を参照して簡単に説明する。 As described above, when the transmission signal 802 in which the suppression component 822 is superimposed on the transmission signal 801 is amplified, the nonlinear distortion component 821 caused by the nonlinearity of the amplifier is canceled out by the suppression component 822, and thus only the original transmission signal is amplified. signal 812 is output. Here, a configuration example of an amplifying apparatus that performs such processing will be briefly described with reference to the drawings.
　図２は、増幅器の有する非線形特性に起因する非線形歪み成分を抑制する増幅装置７００の一構成例を示すブロック図である。増幅装置７００は、入力端子７０１から供給された送信信号に変調および周波数変換の処理を施して、その処理が施された送信信号を増幅する。 FIG. 2 is a block diagram showing a configuration example of an amplifying apparatus 700 that suppresses nonlinear distortion components caused by nonlinear characteristics of the amplifier. The amplifying apparatus 700 performs modulation and frequency conversion processing on the transmission signal supplied from the input terminal 701, and amplifies the transmission signal subjected to the processing.
　増幅装置７００は、振幅算出部７１０と、抑制係数抽出部７２０と、乗算部７３０と、変調部７４０と、Ｄ／Ａ（Digital　to　Analog）変換部７５０と、乗算部７６０と、増幅部７７０と、方向性結合器７８０と、周波数発振部７９０と、を備える。これらに加えて、増幅装置７００は、乗算部８１０と、Ａ／Ｄ（Analog　to　Digital）変換部８２０と、復調部８３０と、帰還信号保持部８４０と、送信信号保持部８５０と、抑制係数算出部８６０と、抑制係数保持部８７０と、を備える。 The amplification device 700 includes an amplitude calculation unit 710, a suppression coefficient extraction unit 720, a multiplication unit 730, a modulation unit 740, a D / A (Digital to Analog) conversion unit 750, a multiplication unit 760, and an amplification unit 770. The directional coupler 780 and the frequency oscillation unit 790 are provided. In addition to these, the amplifying apparatus 700 includes a multiplication unit 810, an A / D (Analog to Digital) conversion unit 820, a demodulation unit 830, a feedback signal holding unit 840, a transmission signal holding unit 850, and a suppression coefficient calculation. Unit 860 and a suppression coefficient holding unit 870.
　この例では、送信信号が入力端子７０１から信号線７０９を介して、振幅算出部７１０、乗算部７３０および送信信号保持部８５０に供給される。また、送信信号は、送信すべき情報が複素数により表現されたベースバンド信号である。 In this example, the transmission signal is supplied from the input terminal 701 to the amplitude calculation unit 710, the multiplication unit 730, and the transmission signal holding unit 850 via the signal line 709. The transmission signal is a baseband signal in which information to be transmitted is expressed by a complex number.
　振幅算出部７１０は、複素数により表現された送信信号の振幅を算出する絶対値算出器である。振幅算出部７１０は、送信信号を表現する複素数の絶対値を、送信信号の振幅として算出する。具体的には、振幅算出部７１０は、送信信号を表現する複素数の実部および虚部の数値をそれぞれ２乗して、これらの和の平方根を、送信信号の振幅として算出する。また、振幅算出部７１０は、その算出された振幅を抑制係数抽出部７２０に供給する。 The amplitude calculation unit 710 is an absolute value calculator that calculates the amplitude of a transmission signal expressed by a complex number. The amplitude calculation unit 710 calculates the absolute value of a complex number representing the transmission signal as the amplitude of the transmission signal. Specifically, amplitude calculation section 710 squares the numerical values of the real part and imaginary part of the complex number representing the transmission signal, and calculates the square root of these sums as the amplitude of the transmission signal. In addition, the amplitude calculation unit 710 supplies the calculated amplitude to the suppression coefficient extraction unit 720.
　抑制係数抽出部７２０は、増幅器７７０の有する非線形特性に起因する非線形歪み成分を抑制するための抑制係数を、抑制係数保持部８７０から抽出する。この抑制係数は、増幅器７７０の有する入出力特性の非線形性を相殺するための特性を有するため、送信信号の振幅の大きさに応じて変化する。このため、抑制係数抽出部７２０は、振幅算出部７１０からの振幅の大きさに基づいて、抑制係数保持部８７０から抑制係数を抽出する。 The suppression coefficient extraction unit 720 extracts, from the suppression coefficient holding unit 870, a suppression coefficient for suppressing a nonlinear distortion component caused by the nonlinear characteristics of the amplifier 770. Since this suppression coefficient has a characteristic for canceling the nonlinearity of the input / output characteristic of the amplifier 770, it changes according to the amplitude of the transmission signal. For this reason, the suppression coefficient extraction unit 720 extracts the suppression coefficient from the suppression coefficient holding unit 870 based on the amplitude magnitude from the amplitude calculation unit 710.
　すなわち、抑制係数抽出部７２０は、抑制係数保持部８７０に保持された抑制係数のうち、振幅算出部７１０からの振幅の大きさに対応する抑制係数を抽出する。また、抑制係数抽出部７２０は、その抽出した抑制係数を乗算部７３０に供給する。 That is, the suppression coefficient extraction unit 720 extracts a suppression coefficient corresponding to the magnitude of the amplitude from the amplitude calculation unit 710 out of the suppression coefficients held in the suppression coefficient holding unit 870. In addition, the suppression coefficient extraction unit 720 supplies the extracted suppression coefficient to the multiplication unit 730.
　乗算部７３０は、入力端子７０１からの送信信号に、抑制係数抽出部７２０からの抑制係数を乗算することによって、増幅器７７０の有する非線形特性に起因する非線形歪み成分を相殺するための抑制成分を送信信号に重畳する複素乗算手段である。乗算部７３０は、信号線７３９を介して、その乗算結果を、歪抑制送信信号として変調部７４０に出力する。この歪抑制送信信号は、いわゆるプリディスト－ション信号である。なお、歪抑制送信信号は、一般的に歪抑制入力信号と呼ぶことができる。 Multiplier 730 multiplies the transmission signal from input terminal 701 by the suppression coefficient from suppression coefficient extraction unit 720, thereby transmitting a suppression component for canceling the nonlinear distortion component due to the nonlinear characteristics of amplifier 770. Complex multiplication means for superimposing on a signal. Multiplier 730 outputs the multiplication result to modulator 740 as a distortion-suppressed transmission signal via signal line 739. This distortion suppression transmission signal is a so-called predistortion signal. Note that a distortion-suppressed transmission signal can be generally called a distortion-suppressed input signal.
　変調部７４０は、乗算部７３０からの歪抑制送信信号に変調処理を施す。変調部７４０は、例えば、中間周波数（Intermediate　Frequency）からなる搬送波信号に歪抑制送信信号を重畳する。また、変調部７４０は、その歪抑制送信信号が重畳された搬送波信号を、変調信号としてＤ／Ａ変換部７５０に供給する。 The modulation unit 740 performs modulation processing on the distortion-suppressed transmission signal from the multiplication unit 730. For example, the modulation unit 740 superimposes the distortion-suppressed transmission signal on a carrier wave signal having an intermediate frequency (Intermediate Frequency). Also, the modulation unit 740 supplies the carrier wave signal on which the distortion-suppressed transmission signal is superimposed to the D / A conversion unit 750 as a modulation signal.
　Ｄ／Ａ変換部７５０は、デジタル信号である変調信号を、アナログ信号に変換する。Ｄ／Ａ変換部７５０は、信号線７５９を介して、そのアナログ信号に変換された変調信号を乗算部７６０に供給する。 The D / A converter 750 converts the modulation signal, which is a digital signal, into an analog signal. The D / A conversion unit 750 supplies the modulation signal converted into the analog signal to the multiplication unit 760 via the signal line 759.
　乗算部７６０は、Ｄ／Ａ変換部７５０からの変調信号の周波数を、その周波数よりも高い周波数に変換する。乗算部７６０は、例えば、周波数発振部７９０からの発振信号を変調信号に乗算することによって、変調信号の周波数をＲＦ（Radio　Frequency）帯域に変換する。また、乗算部７６０は、信号線７６９を介して、その周波数変換された変調信号を、ＲＦ信号として増幅部７７０に出力する。 Multiplier 760 converts the frequency of the modulated signal from D / A converter 750 to a frequency higher than that frequency. The multiplier 760 converts the frequency of the modulated signal into an RF (Radio Frequency) band, for example, by multiplying the modulated signal by the oscillation signal from the frequency oscillating unit 790. In addition, the multiplication unit 760 outputs the frequency-converted modulated signal to the amplification unit 770 as an RF signal via the signal line 769.
　増幅部７７０は、乗算部７６０からのＲＦ信号である入力信号の電力を増幅する増幅手段である。増幅部７７０は、電力の入出力特性に非線形性を有する。また、増幅部７７０は、信号線７７９を介して、その増幅されたＲＦ信号を、出力信号として方向性結合器７８０に出力する。 The amplifying unit 770 is an amplifying unit that amplifies the power of the input signal that is the RF signal from the multiplying unit 760. The amplifying unit 770 has nonlinearity in power input / output characteristics. In addition, the amplification unit 770 outputs the amplified RF signal to the directional coupler 780 as an output signal via the signal line 779.
　方向性結合器７８０は、増幅部７７０からの出力信号を信号線７８９に出力するとともに、信号線７８８を介して出力信号の一部の電力を、帰還信号として乗算部８１０に出力する結合器である。この帰還信号は、ＲＦ信号の電力が減衰された信号である。 The directional coupler 780 is a coupler that outputs the output signal from the amplifying unit 770 to the signal line 789 and outputs part of the power of the output signal to the multiplier 810 as a feedback signal via the signal line 788. is there. This feedback signal is a signal in which the power of the RF signal is attenuated.
　乗算部８１０は、周波数発振部７９０からの発振信号と、方向性結合器７８０からの帰還信号と、の乗算によって、帰還信号の周波数を中間周波数に変換する。乗算部８１０は、信号線８１９を介して、その周波数変換された帰還信号をＡ／Ｄ変換部８２０に出力する。 Multiplication unit 810, an oscillation signal from the frequency oscillation unit 790, a feedback signal from the directional coupler 780, the multiplication of, for converting the frequency of the feedback signal to an intermediate frequency. Multiplier 810 outputs the frequency-converted feedback signal to A / D converter 820 via signal line 819.
　Ａ／Ｄ変換部８２０は、乗算部８１０からのアナログ信号である帰還信号をデジタル信号に変換する。Ａ／Ｄ変換部８２０は、そのデジタル信号に変換された帰還信号を、復調部８３０に供給する。 The A / D conversion unit 820 converts the feedback signal that is an analog signal from the multiplication unit 810 into a digital signal. The A / D conversion unit 820 supplies the feedback signal converted into the digital signal to the demodulation unit 830.
　復調部８３０は、Ａ／Ｄ変換部８２０からの帰還信号に、変調部７４０の変調処理に対応する復調処理を施す。復調部８３０は、その復調処理が施された帰還信号を、信号線８３９を介して帰還信号保持部８４０に保持する。 The demodulation unit 830 performs a demodulation process corresponding to the modulation process of the modulation unit 740 on the feedback signal from the A / D conversion unit 820. The demodulating unit 830 holds the demodulated feedback signal in the feedback signal holding unit 840 via the signal line 839.
　帰還信号保持部８４０は、復調部８３０からの帰還信号を保持するメモリである。送信信号保持部８５０は、入力端子７０１から供給された送信信号を保持するメモリである。帰還信号保持部８４０に保持される帰還信号は、送信信号保持部８５０に保持された送信信号が増幅部７７０により増幅された信号である。 The feedback signal holding unit 840 is a memory that holds the feedback signal from the demodulation unit 830. The transmission signal holding unit 850 is a memory that holds a transmission signal supplied from the input terminal 701. The feedback signal held in the feedback signal holding unit 840 is a signal obtained by amplifying the transmission signal held in the transmission signal holding unit 850 by the amplification unit 770.
　抑制係数算出部８６０は、入力端子７０１からの送信信号に乗算するための抑制係数を算出する。抑制係数算出部８６０は、帰還信号保持部８４０および送信信号保持部８５０を参照し、送信信号と、その送信信号に対応する帰還信号と、に基づいて、増幅部７７０の非線形特性に応じた抑制係数を算出する。 The suppression coefficient calculation unit 860 calculates a suppression coefficient for multiplying the transmission signal from the input terminal 701. The suppression coefficient calculation unit 860 refers to the feedback signal holding unit 840 and the transmission signal holding unit 850, and based on the transmission signal and the feedback signal corresponding to the transmission signal, the suppression coefficient according to the nonlinear characteristic of the amplification unit 770 to calculate the coefficient.
　抑制係数算出部８６０は、例えば、送信信号および帰還信号の差分である誤差信号の大きさが最小となるように、抑制係数を算出する。制御係数算出部８６０は、例えば、中央演算処理装置（ＤＳＰ：Digital　Signal　Processor）により実現される。 The suppression coefficient calculation unit 860 calculates the suppression coefficient so that, for example, the magnitude of the error signal that is the difference between the transmission signal and the feedback signal is minimized. The control coefficient calculation unit 860 is realized by, for example, a central processing unit (DSP: Digital Signal Processor).
　また、抑制係数算出部８６０は、その算出された抑制係数を、抑制係数保持部８７０に保持する。また、抑制係数算出部８６０は、その抑制係数を算出するたびに、抑制係数保持部８７０における抑制係数を保持すべき領域に重ねて保持（上書き）する。 Further, the suppression coefficient calculation unit 860 holds the calculated suppression coefficient in the suppression coefficient holding unit 870. In addition, every time the suppression coefficient is calculated, the suppression coefficient calculation unit 860 holds (overwrites) the suppression coefficient in the suppression coefficient holding unit 870 so as to overlap the area to be held.
　抑制係数保持部８７０は、抑制係数算出部８６０により算出された抑制係数を保持するメモリである。抑制係数保持部８７０は、例えば、ルックアップテーブルにより実現される。 The suppression coefficient holding unit 870 is a memory that holds the suppression coefficient calculated by the suppression coefficient calculation unit 860. The suppression coefficient holding unit 870 is realized by, for example, a lookup table.
　次に、増幅装置７００の各構成部により生成される信号の振幅特性について図面を参照して説明する。 Next, amplitude characteristics of signals generated by each component of the amplification device 700 will be described with reference to the drawings.
　図３ａ～図３ｇは、増幅装置７００における各信号線に出力される信号の振幅特性を例示する図である。この例では、縦軸を、デシベル（ｄＢ）単位により表わされた振幅とし、横軸を周波数とする。 3A to 3G are diagrams illustrating the amplitude characteristics of signals output to the signal lines in the amplification device 700. FIG. In this example, the vertical axis is the amplitude expressed in decibel (dB) units, and the horizontal axis is the frequency.
　図３ａは、入力端子７０１から信号線７０９を介して供給される送信信号の振幅特性７０２を示す。振幅特性７０２は、送信信号の中心周波数が「０Ｈｚ」であり、周波数帯域幅ＢＷの波形を示す。なお、この送信信号は複素数により表わされているため、負の周波数を取り得る。 FIG. 3 a shows the amplitude characteristic 702 of the transmission signal supplied from the input terminal 701 via the signal line 709. The amplitude characteristic 702 indicates a waveform with a center frequency of the transmission signal of “0 Hz” and a frequency bandwidth BW. Since this transmission signal is represented by a complex number, it can take a negative frequency.
　図３ｂは、乗算部７３０から信号線７３９を介して出力される歪抑制送信信号の振幅特性７３１を示す。振幅特性７３１には、抑制係数抽出部７２０からの抑制係数が送信信号に乗算されることによって生成された抑制成分７３２が重畳される。 FIG. 3 b shows the amplitude characteristic 731 of the distortion-suppressed transmission signal output from the multiplier 730 via the signal line 739. A suppression component 732 generated by multiplying the transmission signal by the suppression coefficient from the suppression coefficient extraction unit 720 is superimposed on the amplitude characteristic 731.
　図３ｃは、Ｄ／Ａ変換部７５０から信号線７５９を介して出力される変調信号の振幅特性７５１を示す。振幅特性７５１の中心周波数は、変調部７４０により変調処理が施されるため、中間周波数ｆ_ｉｆを示す。 FIG. 3 c shows an amplitude characteristic 751 of the modulation signal output from the D / A conversion unit 750 via the signal line 759. The center frequency of the amplitude characteristic 751 is subjected to modulation processing by the modulation unit 740, and thus indicates an intermediate frequency f_if.
　図３ｄは、乗算部７６０から信号線７６９を介して出力されるＲＦ信号の振幅特性７６１を示す。振幅特性７６１の中心周波数は、乗算部７６０により周波数変換されたため、ＲＦ周波数ｆ_ｒｆを示す。 FIG. 3d shows the amplitude characteristic 761 of the RF signal output from the multiplier 760 via the signal line 769. Since the center frequency of the amplitude characteristic 761 is frequency-converted by the multiplier 760, it indicates the RF frequency f_rf.
　図３ｅは、増幅部７７０から信号線７７９を介して出力されるＲＦ信号の振幅特性７７１を示す。振幅特性７７１は、図３ｄに示された抑制成分７６２が、増幅部７７０の非線形特性により生じる非線形歪み成分を相殺するため、非線形歪み成分が除去された振幅特性を示す。 FIG. 3 e shows an amplitude characteristic 771 of the RF signal output from the amplifying unit 770 via the signal line 779. The amplitude characteristic 771 shows the amplitude characteristic from which the nonlinear distortion component is removed because the suppression component 762 shown in FIG. 3d cancels the nonlinear distortion component caused by the nonlinear characteristic of the amplification unit 770.
　図３ｆは、乗算部８１０から信号線８１９を介して出力される帰還信号の振幅特性８１１を示す。振幅特性８８１の中心周波数は、乗算部７６０により周波数変換されたため、中間周波数ｆ_ｉｆを示す。 FIG. 3 f shows the amplitude characteristic 811 of the feedback signal output from the multiplier 810 via the signal line 819. Since the center frequency of the amplitude characteristic 881 is frequency-converted by the multiplier 760, it indicates the intermediate frequency f_if.
　図３ｇは、復調部８３０から信号線８３９を介して出力される帰還信号の振幅特性８３１を示す。振幅特性８３１の中心周波数は、復調部８３０により復調処理が施されたため、「０Ｈｚ」を示す。この帰還信号はベースバンド信号である。 FIG. 3g shows the amplitude characteristic 831 of the feedback signal output from the demodulator 830 via the signal line 839. The center frequency of the amplitude characteristic 831 indicates “0 Hz” because the demodulation processing is performed by the demodulation unit 830. This feedback signal is a baseband signal.
　このように、増幅装置７００は、乗算部７３０において抑制係数抽出部７２０からの抑制係数を送信信号に乗算することによって、増幅部７７０の非線形特性に起因する非線形歪み成分を抑制する。 As described above, the amplifying apparatus 700 suppresses the nonlinear distortion component caused by the nonlinear characteristic of the amplifying unit 770 by multiplying the transmission signal by the suppression coefficient from the suppression coefficient extracting unit 720 in the multiplying unit 730.
　しかしながら、このような増幅装置では、増幅部の有する周波数特性によって非線形歪み成分の周波数特性が変化する。このため、抑制成分を送信信号に付加しただけでは増幅部の出力信号に歪み成分の一部が残留するという問題があった。特に、増幅部の出力信号の電力が大きい場合、または、増幅部に入力される信号が広帯域キャリアの場合には、非線形歪み成分の周波数特性の変化が顕著になって、増幅部の出力信号に残留する歪み成分が大きくなってしまう。 However, in such an amplifying apparatus, the frequency characteristic of the nonlinear distortion component changes depending on the frequency characteristic of the amplifying unit. For this reason, there is a problem in that a part of the distortion component remains in the output signal of the amplification unit only by adding the suppression component to the transmission signal. In particular, when the power of the output signal of the amplifying unit is large, or when the signal input to the amplifying unit is a broadband carrier, the change in the frequency characteristic of the nonlinear distortion component becomes significant, and the output signal of the amplifying unit remaining distortion component is increased.
　図４ａ～図４ｄは、増幅部の周波数特性に起因する非線形歪み成分の周波数変動に関する図である。図４ａに示された振幅特性８０１の送信信号が、入出力特性に非線形性を有し、かつ、周波数特性を有する増幅部に入力されると、その増幅部の出力信号には、図４ｂに示された歪み成分８３２が、増幅部の周波数特性の影響によって生じる。このように、増幅部の周波数特性に起因して非線形歪み成分８３２が非対称の振幅特性を示すことを、ここではメモリ効果という。 4a to 4d are diagrams relating to frequency fluctuations of nonlinear distortion components caused by the frequency characteristics of the amplification unit. When the transmission signal having the amplitude characteristic 801 shown in FIG. 4a is input to an amplification unit having nonlinearity in input / output characteristics and having frequency characteristics, the output signal of the amplification unit is shown in FIG. 4b. The distortion component 832 shown is generated due to the influence of the frequency characteristic of the amplification unit. Thus, the fact that the nonlinear distortion component 832 exhibits an asymmetric amplitude characteristic due to the frequency characteristic of the amplifying unit is referred to as a memory effect here.
　このため、上述のとおり、図４ｃに示された抑制成分８２２を送信信号に重畳しても、図４ｄに示された増幅部の出力信号８４１には、残留成分８４２が残ってしまう。 Therefore, as described above, even if the suppression component 822 shown in FIG. 4c is superimposed on the transmission signal, the residual component 842 remains in the output signal 841 of the amplification unit shown in FIG. 4d.
　このような問題を解決する技術が特許文献１に記載されている。特許文献１に記載の歪み補償装置は、複素ディジタルフィルタが、電力増幅器を含むアナログ回路部における振幅特性を補正することによって、電力増幅器の出力信号に含まれる歪み成分を抑制する。 A technique for solving such a problem is described in Patent Document 1. Distortion compensating apparatus according to Patent Document 1, the complex digital filter, by correcting the amplitude characteristic in the analog circuit unit including a power amplifier, suppressing the distortion component included in the output signal of the power amplifier.
特開２００４－１２８８３３号公報（図１）JP 2004-128833 A (FIG. 1)
　特許文献１に記載の歪み補償装置では、適応イコライザが、複数のフィルタ係数のうち、複素ディジタルフィルタに設定すべきフィルタ係数を、電力増幅器からのフィードバック信号に基づいて選択するが、このような処理を行う回路が必要となるため、回路規模が増大するという課題があった。 In the distortion compensation apparatus described in Patent Document 1, the adaptive equalizer selects a filter coefficient to be set in the complex digital filter from among a plurality of filter coefficients based on a feedback signal from the power amplifier. Therefore, there is a problem that the circuit scale increases.
　本発明の目的は、上記した課題を解決する増幅装置、歪み補償回路および歪み補償方法を提供することにある。 An object of the present invention is to provide an amplifier, a distortion compensation circuit, and a distortion compensation method that solve the above-described problems.
　本発明の歪み補償回路は、電力を増幅する増幅手段に供給される増幅対象信号を生成するための入力信号を受け付ける入力端子と、前記増幅手段の有する入出力特性の非線形性に起因する前記増幅手段の出力信号の歪み成分を抑制するための抑制係数を前記入力信号に乗算することによって歪抑制入力信号を生成する乗算手段と、前記入力信号と前記歪抑制入力信号との差分信号の周波数成分のうち複数の周波数範囲の各々に対応する周波数成分を前記周波数範囲ごとに抽出信号として抽出する抽出手段と、前記増幅手段の有する周波数特性に起因する前記歪み成分の周波数特性の変化を補正するための補正係数を前記周波数範囲ごとに保持する補正係数保持手段と、前記周波数範囲ごとに前記補正係数を前記抽出信号に乗算することによって前記周波数範囲ごとの補正信号を生成する補正信号生成手段と、前記周波数範囲ごとの補正信号と前記歪抑制入力信号とに基づいて、前記増幅対象信号を生成する増幅対象信号生成手段と、を含む。 The distortion compensation circuit of the present invention includes an input terminal that receives an input signal for generating an amplification target signal supplied to an amplification unit that amplifies power, and the amplification caused by nonlinearity of input / output characteristics of the amplification unit Multiplication means for generating a distortion suppression input signal by multiplying the input signal by a suppression coefficient for suppressing a distortion component of the output signal of the means, and a frequency component of a difference signal between the input signal and the distortion suppression input signal extracting means for extracting a frequency component as an extraction signal for each of said frequency ranges corresponding to each of a plurality of frequency ranges of, for correcting the change in the frequency characteristic of the distortion components due to the frequency characteristic possessed by the amplifying means Correction coefficient holding means for holding the correction coefficient for each frequency range, and multiplying the extracted signal by the correction coefficient for each frequency range. A correction signal generating means for generating a correction signal for each of the frequency ranges Te, on the basis of the correction signal and the distortion suppression input signal for each frequency range, and the amplified signal generating means for generating the amplified signal, the including.
　本発明の増幅装置は、電力の入出力特性に非線形性を有し、かつ、周波数特性を有する増幅手段を備え、入力信号を増幅する増幅装置であって、前記増幅手段の有する非線形性に起因する前記増幅手段の出力信号の歪み成分を抑制するための抑制係数と、前記入力信号と、を乗算することによって歪抑制入力信号を生成する乗算手段と、前記入力信号と前記歪抑制入力信号との差分信号の周波数成分のうち複数の周波数範囲の各々に対応する周波数成分を前記周波数範囲ごとに抽出信号として抽出する抽出手段と、前記増幅手段の有する周波数特性に起因する前記歪み成分の周波数特性の変化を補正するための補正係数を前記周波数範囲ごとに保持する補正係数保持手段と、前記周波数範囲ごとに前記補正係数を前記抽出信号に乗算することによって前記周波数範囲ごとの補正信号を生成する補正信号生成手段と、前記周波数範囲ごとの補正信号と、前記歪抑制入力信号と、に基づいて、増幅対象信号を生成する増幅対象信号生成手段と、を含み、前記増幅手段は、前記増幅対象信号を増幅する。 An amplifying apparatus according to the present invention is an amplifying apparatus that amplifies an input signal by having an amplifying unit having nonlinearity in power input / output characteristics and having frequency characteristics, and is caused by the nonlinearity of the amplifying means. Multiplying means for generating a distortion suppression input signal by multiplying the input signal with a suppression coefficient for suppressing a distortion component of the output signal of the amplification means, the input signal and the distortion suppression input signal Extraction means for extracting a frequency component corresponding to each of a plurality of frequency ranges among the frequency components of the difference signal as an extraction signal for each frequency range, and frequency characteristics of the distortion component due to the frequency characteristics of the amplification means Correction coefficient holding means for holding a correction coefficient for correcting a change in each frequency range, and multiplying the extracted signal by the correction coefficient for each frequency range. A correction signal generating means for generating a correction signal for each of the frequency range by a correction signal for each of the frequency ranges, and the distortion suppression input signal, based on the amplified signal generating means for generating an amplified signal, The amplification means amplifies the amplification target signal.
　本発明の歪み補償方法は、電力を増幅する増幅手段に供給される増幅対象信号を生成するための入力信号を受け付ける入力端子と、前記増幅手段の有する入出力特性の非線形性に起因する前記増幅手段の出力信号の歪み成分を抑制するための抑制係数を保持する抑制係数保持手段と、前記増幅手段の有する周波数特性に起因する前記歪み成分の周波数特性の変化を補正するための補正係数を複数の周波数範囲ごとに保持する補正係数保持手段と、を含む歪み補償回路における歪み補償方法であって、前記入力信号に前記抑制係数を乗算することによって歪抑制入力信号を生成し、前記入力信号と前記歪抑制入力信号との差分信号の周波数成分のうち複数の前記周波数範囲の各々に対応する周波数成分を前記周波数範囲ごとに抽出信号として抽出し、前記周波数範囲ごとに前記補正係数を前記抽出信号に乗算することによって前記周波数範囲ごとの補正信号を生成し、前記周波数範囲ごとの前記補正信号と前記歪抑制入力信号とに基づいて、前記増幅対象信号を生成する。 The distortion compensation method of the present invention includes: an input terminal that receives an input signal for generating an amplification target signal supplied to an amplification unit that amplifies power; and the amplification caused by nonlinearity of input / output characteristics of the amplification unit A plurality of suppression coefficient holding means for holding a suppression coefficient for suppressing a distortion component of the output signal of the means, and a plurality of correction coefficients for correcting a change in the frequency characteristic of the distortion component caused by the frequency characteristic of the amplification means. A correction coefficient holding means for holding each frequency range, a distortion compensation method in a distortion compensation circuit, generating a distortion suppression input signal by multiplying the input signal by the suppression coefficient, and the input signal Of the frequency components of the difference signal from the distortion suppression input signal, frequency components corresponding to each of the plurality of frequency ranges are extracted signals for each frequency range. Generating a correction signal for each frequency range by multiplying the extraction signal by the correction coefficient for each frequency range, and based on the correction signal and the distortion suppression input signal for each frequency range, to generate an amplified signal of interest.
　本発明によれば、回路規模を抑えつつ、増幅器の出力信号に含まれる歪み成分を低減することが可能になる。 According to the present invention, it is possible to reduce the distortion component contained in the output signal of the amplifier while suppressing the circuit scale.
入出力特性に非線形性を有する増幅器に入力される送信信号の振幅特性を示す図である。It is a figure which shows the amplitude characteristic of the transmission signal input into the amplifier which has nonlinearity in input-output characteristics. 図１ａに示された送信信号が増幅された場合における増幅器の出力信号の振幅特性を示す図である。It is a figure which shows the amplitude characteristic of the output signal of an amplifier when the transmission signal shown by FIG. 1a is amplified. 図１ａに示された送信信号に抑制成分が付加された送信信号の振幅特性を示す図である。It is a figure which shows the amplitude characteristic of the transmission signal by which the suppression component was added to the transmission signal shown by FIG. 図１ｃに示された送信信号が増幅された場合における増幅器の出力信号の振幅特性を示す図である。It is a figure which shows the amplitude characteristic of the output signal of an amplifier when the transmission signal shown by FIG. 1c is amplified. 非線形歪み成分を抑制する増幅装置の一構成例を示すブロック図である。It is a block diagram which shows one structural example of the amplifier which suppresses a nonlinear distortion component. 入力端子７０１から供給される送信信号の振幅特性を示す。The amplitude characteristic of the transmission signal supplied from the input terminal 701 is shown. 乗算部７３０から出力される歪抑制送信信号の振幅特性を示す。The amplitude characteristic of the distortion suppression transmission signal output from the multiplication part 730 is shown. Ｄ／Ａ変換部７５０から出力される変調信号の振幅特性を示す。The amplitude characteristic of the modulation signal output from the D / A conversion unit 750 is shown. 乗算部７６０から出力されるＲＦ信号の振幅特性を示す。The amplitude characteristic of the RF signal output from the multiplier 760 is shown. 増幅部７７０から出力されるＲＦ信号の振幅特性を示す。The amplitude characteristic of the RF signal output from the amplification unit 770 is shown. 乗算部８１０から出力される帰還信号の振幅特性を示す。The amplitude characteristic of the feedback signal output from the multiplier 810 is shown. 復調部８３０から出力される帰還信号の振幅特性を示す。The amplitude characteristic of the feedback signal output from the demodulator 830 is shown. 入出力特性に非線形性を有し、かつ、周波数特性を有する増幅器に入力される送信信号の振幅特性を示す図である。It is a figure which shows the amplitude characteristic of the transmission signal input into the amplifier which has nonlinearity in an input-output characteristic, and has a frequency characteristic. 図４ａに示された送信信号が増幅された場合における増幅器の出力信号の振幅特性を示す図である。FIG. 4B is a diagram illustrating amplitude characteristics of an output signal of an amplifier when the transmission signal illustrated in FIG. 4A is amplified. 抑制成分が重畳された送信信号の振幅特性を示す図である。It is a figure which shows the amplitude characteristic of the transmission signal with which the suppression component was superimposed. 増幅器の出力信号の非線形歪み成分の一部が残留する例を示す図である。It is a figure which shows the example in which a part of nonlinear distortion component of the output signal of an amplifier remains. 本発明の実施形態における増幅装置を示すブロック図である。It is a block diagram which shows the amplification apparatus in embodiment of this invention. 周波数特性補正部３００の一構成例を示すブロック図である。3 is a block diagram illustrating an example of a configuration of a frequency characteristic correction unit 300. FIG. 低域通過フィルタ３５１の振幅特性の一例を示す図である。It is a figure which shows an example of the amplitude characteristic of the low-pass filter 351. 低域通過フィルタ３５２の振幅特性の一例を示す図である。It is a figure which shows an example of the amplitude characteristic of the low-pass filter 352. 周波数特性補正部３００に入力される送信信号の振幅特性を示す図である。6 is a diagram illustrating amplitude characteristics of a transmission signal input to a frequency characteristic correction unit 300. FIG. 周波数特性補正部３００に入力される歪抑制送信信号の振幅特性を示す図である。6 is a diagram illustrating amplitude characteristics of a distortion-suppressed transmission signal input to a frequency characteristic correction unit 300. FIG. 非線形歪み成分の低域側が低く、高域側が高くなる出力信号の振幅特性を示す。The amplitude characteristic of the output signal in which the low frequency side of the nonlinear distortion component is low and the high frequency side is high is shown. 非線形歪み成分の低域側が高く、高域側が低くなる出力信号の振幅特性を示す。The amplitude characteristic of the output signal in which the low frequency side of the nonlinear distortion component is high and the high frequency side is low is shown. 非線形歪み成分の低域側および高域側が高くなる出力信号の振幅特性を示す。The amplitude characteristic of the output signal in which the low frequency side and the high frequency side of the nonlinear distortion component are increased is shown. 非線形歪み成分の低域側および高域側が低くなる出力信号の振幅特性を示す。The amplitude characteristic of the output signal in which the low frequency side and the high frequency side of the nonlinear distortion component are low is shown. 増幅装置１００における歪み補償方法の処理手順例を示すフローチャートである。5 is a flowchart illustrating an example of a processing procedure of a distortion compensation method in the amplification device 100.
　以下、本発明の一実施形態について図面を参照して説明する。　
　図５は、本発明の実施形態における増幅装置を示すブロック図である。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 5 is a block diagram illustrating an amplifying apparatus according to an embodiment of the present invention.
　増幅装置１００は、入力端子１０１からの送信信号を変調および周波数変換の処理を施して、その処理が施された送信信号を増幅する。また、入力端子１０１からの送信信号は、送信すべき情報が複素数により表現されたベースバンド信号である。なお、送信信号は、一般的に入力信号と呼ぶことができる。 The amplifying apparatus 100 performs modulation and frequency conversion processing on the transmission signal from the input terminal 101, and amplifies the transmission signal subjected to the processing. The transmission signal from the input terminal 101 is a baseband signal in which information to be transmitted is expressed by a complex number. A transmission signal can generally be referred to as an input signal.
　増幅装置１００は、変調部１１０と、Ｄ／Ａ変換部１２０と、乗算部１３０と、増幅部１４０と、方向性結合器１５０と、周波数発振部１６０と、乗算部１７０と、Ａ／Ｄ変換部１８０と、復調部１９０と、歪み補償回路２００を備える。また、歪み補償回路２００は、振幅算出部２１０と、抑制係数抽出部２２０と、乗算部２３０と、帰還信号保持部２４０と、送信信号保持部２５０と、抑制係数算出部２６０と、抑制係数保持部２７０と、を備える。さらに、歪み補償回路２００は、周波数特性補正部３００と、補正係数設定部３１０と、補正係数保持部３２０と、を備える。 The amplification device 100 includes a modulation unit 110, a D / A conversion unit 120, a multiplication unit 130, an amplification unit 140, a directional coupler 150, a frequency oscillation unit 160, a multiplication unit 170, and an A / D conversion. Unit 180, demodulator 190, and distortion compensation circuit 200. In addition, the distortion compensation circuit 200 includes an amplitude calculation unit 210, a suppression coefficient extraction unit 220, a multiplication unit 230, a feedback signal holding unit 240, a transmission signal holding unit 250, a suppression coefficient calculation unit 260, and a suppression coefficient holding. It includes a section 270, a. Furthermore, the distortion compensation circuit 200 includes a frequency characteristic correction unit 300, a correction coefficient setting unit 310, and a correction coefficient holding unit 320.
　なお、変調部１１０、Ｄ／Ａ変換部１２０、乗算部１３０、増幅部１４０および方向性結合器１５０は、それぞれ、変調部７４０、Ｄ／Ａ変換部７５０、乗算部７６０、増幅部７７０および方向性結合器７８０と同一構成である。なお、増幅部１４０は、一般的に増幅手段と呼ぶことができる。また、周波数発振部１６０、乗算部１７０、Ａ／Ｄ変換部１８０および復調部１９０は、それぞれ、周波数発振部７９０、乗算部８１０、Ａ／Ｄ変換部８２０および復調部８３０と同一構成である。 The modulation unit 110, the D / A conversion unit 120, the multiplication unit 130, the amplification unit 140, and the directional coupler 150 are the modulation unit 740, the D / A conversion unit 750, the multiplication unit 760, the amplification unit 770, and the direction, respectively. a sexual coupler 780 of the same configuration. Amplifying section 140 can generally be referred to as an amplifying means. Further, the frequency oscillation unit 160, the multiplication unit 170, the A / D conversion unit 180, and the demodulation unit 190 have the same configuration as the frequency oscillation unit 790, the multiplication unit 810, the A / D conversion unit 820, and the demodulation unit 830, respectively.
　さらに、振幅算出部２１０、抑制係数抽出部２２０および乗算部２３０は、それぞれ、振幅算出部７１０、抑制係数抽出部７２０および乗算部７３０と同一構成である。なお、乗算部２３０は、一般的に乗算手段と呼ぶことができる。また、帰還信号保持部２４０、送信信号保持部２５０、抑制係数算出部２６０および抑制係数保持部２７０は、それぞれ、帰還信号保持部８４０、送信信号保持部８５０、抑制係数算出部８６０および抑制係数保持部８７０と同一構成である。 Furthermore, the amplitude calculation unit 210, the suppression coefficient extraction unit 220, and the multiplication unit 230 have the same configuration as the amplitude calculation unit 710, the suppression coefficient extraction unit 720, and the multiplication unit 730, respectively. Multiplier 230 can be generally referred to as multiplication means. The feedback signal holding unit 240, the transmission signal holding unit 250, the suppression coefficient calculation unit 260, and the suppression coefficient holding unit 270 are respectively a feedback signal holding unit 840, a transmission signal holding unit 850, a suppression coefficient calculation unit 860, and a suppression coefficient holding. part 870 is the same as the configuration.
　また、周波数特性補正部３００、補正係数設定部３１０および補正係数保持部３２０以外の他の構成については、図２に示した構成と同様のものであるため、ここでの説明を省略する。 Also omitted, the frequency characteristic correcting portion 300, for other configurations other than the correction coefficient setting unit 310 and the correction coefficient holding unit 320, because it is similar to the configuration shown in FIG. 2, the description herein.
　補正係数設定部３１０は、乗算部２３０からの歪抑制送信信号の周波数特性を補正するための補正係数を、補正係数保持部３２０に保持させる。 The correction coefficient setting unit 310 causes the correction coefficient holding unit 320 to hold a correction coefficient for correcting the frequency characteristics of the distortion-suppressed transmission signal from the multiplication unit 230.
　補正係数設定部３１０は、増幅装置１００の使用者による補正係数の設定に関する操作を受け付ける。このとき、増幅装置１００の使用者は、補正係数の値を順次変更し、増幅部１４０の出力信号のスペクトラムを測定して、出力信号の歪み成分が最小となる値を、補正係数設定部３１０に入力する操作を行う。補正係数設定部３１０は、その受け付けた操作に基づいて、補正係数の値を補正係数保持部３２０に設定する。 The correction coefficient setting unit 310 receives an operation related to the setting of the correction coefficient by the user of the amplification device 100. At this time, the user of the amplifying apparatus 100 sequentially changes the value of the correction coefficient, measures the spectrum of the output signal of the amplifying unit 140, and determines the value that minimizes the distortion component of the output signal as the correction coefficient setting unit 310. It performs an operation to input to. The correction coefficient setting unit 310 sets the correction coefficient value in the correction coefficient holding unit 320 based on the accepted operation.
　補正係数保持部３２０は、補正係数設定部３１０により設定された補正係数を保持するメモリである。すなわち、補正係数保持部３２０は、増幅部１４０の有する周波数特性に起因する非線形歪み成分の周波数特性の変化を補正するための補正係数を保持する。なお、この補正係数は、複素数により表現される。また、補正係数保持部３２０は、信号線３２９を介して、その補正係数を周波数特性補正部３００に出力する。なお、補正係数保持部３２０は、一般的に補正係数保持手段と呼ぶことができる。 The correction coefficient holding unit 320 is a memory that holds the correction coefficient set by the correction coefficient setting unit 310. That is, the correction coefficient holding unit 320 holds a correction coefficient for correcting a change in the frequency characteristic of the nonlinear distortion component caused by the frequency characteristic of the amplification unit 140. This correction coefficient is expressed by a complex number. Further, the correction coefficient holding unit 320 outputs the correction coefficient to the frequency characteristic correction unit 300 via the signal line 329. The correction coefficient holding unit 320 can be generally called correction coefficient holding means.
　周波数特性補正部３００は、増幅部１４０の有する周波数特性に起因する非線形歪み成分の周波数特性の変動を低減するために、歪抑制送信信号の周波数特性を補正する。すなわち、周波数特性補正部３００は、増幅部１４０のメモリ効果によって生じる非線形歪み成分の周波数特性の変動を相殺するために、特定の周波数特性を歪抑制送信信号に付加するメモリ効果キャンセル回路である。 The frequency characteristic correction unit 300 corrects the frequency characteristic of the distortion-suppressed transmission signal in order to reduce the fluctuation of the frequency characteristic of the nonlinear distortion component caused by the frequency characteristic of the amplification unit 140. That is, the frequency characteristic correction unit 300 is a memory effect cancellation circuit that adds a specific frequency characteristic to the distortion-suppressed transmission signal in order to cancel out the fluctuation of the frequency characteristic of the nonlinear distortion component caused by the memory effect of the amplification unit 140.
　周波数特性補正部３００は、入力端子１０１からの送信信号と、補正係数保持部３２０に保持された補正係数と、に基づいて、歪抑制送信信号の周波数特性を補正する。また、周波数特性補正部３００は、信号線３０９を介して、その補正された歪抑制送信信号を、変調部１１０に出力する。 The frequency characteristic correction unit 300 corrects the frequency characteristic of the distortion-suppressed transmission signal based on the transmission signal from the input terminal 101 and the correction coefficient held in the correction coefficient holding unit 320. Further, the frequency characteristic correction unit 300 outputs the corrected distortion-suppressed transmission signal to the modulation unit 110 via the signal line 309.
　なお、増幅装置１００は、増幅部１４０、乗算部２３０、周波数特性補正部３００および補正係数保持部３２０のみにより構成されるようにしてもよい。また、歪み補償回路２００は、乗算部２３０、周波数特性補正部３００および補正係数保持部３２０のみにより構成されるようにしてもよい。 Note that the amplifying apparatus 100 may be configured by only the amplifying unit 140, the multiplying unit 230, the frequency characteristic correcting unit 300, and the correction coefficient holding unit 320. Further, the distortion compensation circuit 200 may be configured by only the multiplication unit 230, the frequency characteristic correction unit 300, and the correction coefficient holding unit 320.
　図６は、周波数特性補正部３００の一構成例を示すブロック図である。 FIG. 6 is a block diagram illustrating a configuration example of the frequency characteristic correction unit 300.
　周波数特性補正部３００は、抽出部３５０と、乗算部３６０と、加算部３７０と、を備える。 The frequency characteristic correction unit 300 includes an extraction unit 350, a multiplication unit 360, and an addition unit 370.
　抽出部３５０は、加算器３４０と、低域通過フィルタ３５１と、高域通過フィルタ３５２と、を備える。乗算部３６０は、乗算器３６１および３６２を備える。この例では、補正係数保持部３２０に、低域および高域の補正係数がそれぞれ保持されており、信号線３２９に含まれる信号線３２７および３２８を介して、乗算器３６１および３６２にそれぞれ低域および高域の補正係数が供給されることを想定する。 The extraction unit 350 includes an adder 340, a low-pass filter 351, and a high-pass filter 352. Multiplier 360 includes multipliers 361 and 362. In this example, the low-frequency and high-frequency correction coefficients are held in the correction coefficient holding unit 320, respectively, and the low-frequency is supplied to the multipliers 361 and 362 via the signal lines 327 and 328 included in the signal line 329, respectively. And a high-frequency correction factor is assumed to be supplied.
　抽出部３５０は、信号線１０９からの送信信号と、信号線２３９からの歪抑制送信信号と、の差分信号の周波数成分のうち、複数の周波数範囲の各々に対応する周波数成分を周波数範囲ごとにそれぞれ抽出する。 Extraction unit 350, a transmission signal from the signal line 109, among the frequency components of the distortion suppression transmission signals and, of the differential signal from the signal line 239, a frequency component corresponding to each of a plurality of frequency ranges for each frequency range each extraction.
　抽出部３５０は、送信信号と歪抑制送信信号との差分信号の周波数成分のうち、負の周波数範囲の周波数成分からなる信号と、正の周波数範囲の周波数成分からなる信号と、をそれぞれ抽出する。すなわち、抽出部３５０は、送信信号と歪抑制送信信号との差分信号の周波数成分のうち、その差分信号の全周波数範囲の中程よりも低い周波数範囲と、他の周波数範囲と、に対応する周波数成分を周波数範囲ごとに抽出する。また、抽出部３５０は、その抽出された信号を抽出信号として乗算部３６０にそれぞれ供給する。なお、抽出部３５０は、一般的に抽出手段と呼ぶことができる。 Extracting unit 350, among the frequency components of the difference signal between the transmission signal and the distortion suppression transmission signal, and extracts each signal consisting of frequency components of negative frequency range, a signal composed of the frequency components of the positive frequency range, the . That is, the extraction unit 350 corresponds to a frequency range lower than the middle of the entire frequency range of the difference signal and other frequency ranges among the frequency components of the difference signal between the transmission signal and the distortion suppression transmission signal. extracting a frequency component for each frequency range. The extraction unit 350 supplies the extracted signal to the multiplication unit 360 as an extraction signal. Extraction unit 350 can generally be referred to as extraction means.
　加算器３４０は、信号線１０９からの送信信号と、信号線２３９からの歪抑制送信信号と、の差分を算出することによって、歪抑制送信信号に含まれる抑制成分を抽出する。ここにいう抑制成分とは、増幅部１４０の非線形特性に起因する非線形歪み成分を相殺するための成分であって、乗算部２３０における送信信号と抑制係数との乗算によって生成される成分である。加算器３４０は、その算出結果を、差分信号として、低域通過フィルタ３５１および高域通過フィルタ３５２に出力する。 The adder 340 extracts a suppression component included in the distortion suppression transmission signal by calculating a difference between the transmission signal from the signal line 109 and the distortion suppression transmission signal from the signal line 239. The suppression component referred to here is a component for canceling the nonlinear distortion component caused by the nonlinear characteristic of the amplification unit 140, and is a component generated by multiplication of the transmission signal and the suppression coefficient in the multiplication unit 230. The adder 340 outputs the calculation result as a difference signal to the low-pass filter 351 and the high-pass filter 352.
　低域通過フィルタ３５１および高域通過フィルタ３５２は、差分信号である抑制成分を、低域および高域の周波数範囲に分割するためのフィルタである。低域通過フィルタ３５１および高域通過フィルタ３５２は、例えば、ＦＩＲ（Finite　Impulse　Response）フィルタのようなディジタルフィルタにより実現される。 The low-pass filter 351 and the high-pass filter 352 are filters for dividing a suppression component that is a differential signal into a low-frequency range and a high-frequency range. The low-pass filter 351 and the high-pass filter 352 are realized by a digital filter such as a FIR (Finite Impulse Response) filter, for example.
　低域通過フィルタ３５１は、加算器３４０からの差分信号の周波数成分のうち、その差分信号の中心周波数よりも低い低域の周波数成分を抽出するフィルタである。すなわち、低域通過フィルタ３５１は、抑制成分のうち低域の周波数成分を抽出する。また、低域通過フィルタ３５１は、その抽出された低域の周波数成分を、低域の抽出信号として乗算器３６１に出力する。 The low-pass filter 351 is a filter that extracts a low-frequency component that is lower than the center frequency of the difference signal from the frequency components of the difference signal from the adder 340. That is, the low-pass filter 351 extracts a low-frequency component from the suppression components. Further, the low-pass filter 351 outputs the extracted low-frequency component to the multiplier 361 as a low-frequency extraction signal.
　高域通過フィルタ３５２は、加算器３４０からの差分信号の周波数成分のうち、その差分信号の中心周波数よりも高い高域の周波数成分を抽出するフィルタである。すなわち、高域通過フィルタ３５２は、抑制成分のうち高域の周波数成分を抽出する。また、高域通過フィルタ３５２は、その抽出された高域の周波数成分を、高域の抽出信号として乗算器３６２に出力する。 The high-pass filter 352 is a filter that extracts a high-frequency component higher than the center frequency of the difference signal from the frequency components of the difference signal from the adder 340. That is, the high-pass filter 352 extracts a high-frequency component from the suppression components. The high-pass filter 352 outputs the extracted high-frequency component to the multiplier 362 as a high-frequency extraction signal.
　乗算部３６０は、歪抑制送信信号に含まれる抑制成分に対し特定の周波数特性を与えるために、周波数範囲ごとの抽出信号に、周波数範囲に対応する補正係数を乗算する複素乗算器である。すなわち、乗算部３６０は、補正係数保持部３２０に保持された補正係数を抽出部３５０からの抽出信号に周波数範囲ごとに乗算することによって、周波数範囲ごとの補正信号を生成する。また、乗算部３６０は、その生成された各補正信号を加算部３７０に供給する。なお、乗算部３６０は、一般的に補正信号生成手段と呼ぶことができる。 The multiplication unit 360 is a complex multiplier that multiplies the extracted signal for each frequency range by a correction coefficient corresponding to the frequency range in order to give a specific frequency characteristic to the suppression component included in the distortion suppression transmission signal. That is, the multiplication unit 360, by multiplying each frequency range extraction signal from the extraction unit 350 the correction coefficients held in correction coefficient holding unit 320, it generates a correction signal for each frequency range. The multiplication unit 360 supplies the generated correction signals to the addition unit 370. Multiplier 360 can generally be referred to as a correction signal generating means.
　乗算器３６１は、信号線３２７からの低域補正係数に応じて、歪抑制送信信号における抑制成分の低域の周波数成分を強調または抑圧する。乗算器３６１は、信号線３２７からの低域補正係数を、低域通過フィルタ３５１からの低域の抽出信号に乗算することによって、低域の補正信号を生成する。また、乗算器３６１は、その低域の補正信号を加算部３７０に供給する。 The multiplier 361 emphasizes or suppresses the low frequency component of the suppression component in the distortion suppression transmission signal according to the low frequency correction coefficient from the signal line 327. The multiplier 361 generates a low-frequency correction signal by multiplying the low-frequency correction coefficient from the signal line 327 by the low-frequency extraction signal from the low-pass filter 351. The multiplier 361 supplies the low-frequency correction signal to the adding unit 370.
　乗算器３６２は、信号線３２８からの高域補正係数に応じて、歪抑制送信信号における抑制成分の高域の周波数成分を強調または抑圧する。乗算器３６２は、信号線３２８からの高域補正係数を、高域通過フィルタ３５２からの高域の抽出信号に乗算することによって、高域の補正信号を生成する。また、乗算器３６２は、その高域の補正信号を加算部３７０に供給する。 Multiplier 362 emphasizes or suppresses the high frequency component of the suppression component in the distortion suppression transmission signal in accordance with the high frequency correction coefficient from signal line 328. The multiplier 362 multiplies the high-frequency extracted signal from the high-pass filter 352 by the high-frequency correction coefficient from the signal line 328 to generate a high-frequency correction signal. The multiplier 362 supplies the high-frequency correction signal to the adder 370.
　加算部３７０は、各周波数範囲の補正信号を歪抑制送信信号に加算することによって、抑制成分に特定の周波数特性を与える。加算部３７０は、複数の周波数範囲の各々に対応する補正信号と、信号線２３９からの歪抑制送信信号と、に基づいて、新たな歪抑制送信信号を生成する。なお、新たな歪抑制送信信号は、一般的に増幅対象信号と呼ぶことができる。 The addition unit 370 gives a specific frequency characteristic to the suppression component by adding the correction signal in each frequency range to the distortion suppression transmission signal. Adder 370 generates a new distortion-suppressed transmission signal based on the correction signal corresponding to each of the plurality of frequency ranges and the distortion-suppressed transmission signal from signal line 239. Note that a new distortion-suppressed transmission signal can be generally called an amplification target signal.
　具体的には、加算部３７０は、乗算器３６１からの低域の補正信号と、乗算器３６２からの高域の補正信号と、信号線２３９からの歪抑制送信信号と、を加算することによって、新たな歪抑制送信信号を生成する。すなわち、加算部３７０は、低い周波数範囲および他の周波数範囲の各々に対応する補正信号と、送信信号に抑制係数が乗算された歪抑制送信信号と、を加算することによって、新たな歪抑制送信信号を生成する。また、加算部３７０は、信号線３０９を介して、その新たな歪抑制送信信号を変調部１１０に供給する。なお、加算部３７０は、一般的に増幅対象信号生成手段と呼ぶことができる。なお、この例では、加算部３７０が、新たな歪抑制送信信号を、周波数範囲ごとの補正信号と、信号線２３９からの歪抑制送信信号と、に基づいて生成する例について説明したが、加算部３７０は、周波数範囲ごとの補正信号と、信号線１０９からの送信信号と、に基づいて、新たな歪抑制送信信号を生成するようにしてもよい。 Specifically, the adding unit 370 adds the low-frequency correction signal from the multiplier 361, the high-frequency correction signal from the multiplier 362, and the distortion suppression transmission signal from the signal line 239. generates a new distortion suppression transmission signals. That is, the adding unit 370 adds a correction signal corresponding to each of the low frequency range and the other frequency range and a distortion suppression transmission signal obtained by multiplying the transmission signal by a suppression coefficient, thereby generating a new distortion suppression transmission. to generate a signal. In addition, the adding unit 370 supplies the new distortion-suppressed transmission signal to the modulation unit 110 via the signal line 309. Adder 370 can be generally referred to as amplification target signal generation means. In this example, an example has been described in which the adding unit 370 generates a new distortion suppression transmission signal based on the correction signal for each frequency range and the distortion suppression transmission signal from the signal line 239. The unit 370 may generate a new distortion-suppressed transmission signal based on the correction signal for each frequency range and the transmission signal from the signal line 109.
　なお、この実施形態では、周波数特性補正部３００が、乗算部２３０からの歪抑制送信信号に含まれる抑制成分に基づいてその歪抑制送信信号の周波数特性を補正する例について説明したが、周波数特性補正部３００が、乗算部２３０からの歪抑制送信信号の低域成分および高域成分を用いてその歪抑制送信信号の周波数特性を補正するようにしてもよい。 In this embodiment, the frequency characteristic correction unit 300 corrects the frequency characteristic of the distortion suppression transmission signal based on the suppression component included in the distortion suppression transmission signal from the multiplication unit 230. The correction unit 300 may correct the frequency characteristics of the distortion-suppressed transmission signal using the low-frequency component and the high-frequency component of the distortion-suppressed transmission signal from the multiplication unit 230.
　図７ａおよび図７ｂは、低域通過フィルタ３５１および低域通過フィルタ３５２の振幅特性の一例を示す図である。この例では、縦軸を振幅とし、横軸を周波数とする。また、ｆｓは、送信信号の標本周波数を示す。 7a and 7b are diagrams showing examples of amplitude characteristics of the low-pass filter 351 and the low-pass filter 352. FIG. In this example, the vertical axis is amplitude and the horizontal axis is frequency. Fs indicates the sampling frequency of the transmission signal.
　図７ａは、低域通過フィルタ３５１の振幅特性を示す図である。この振幅特性は、差分信号の中心周波数「０Ｈｚ」近傍から「－ｆｓ／２」近傍までの低域の周波数範囲における振幅利得が大きい。このため、低域通過フィルタ３５１の通過後の差分信号は、差分信号の周波数成分のうち、低域の周波数範囲の周波数成分からなる信号となる。また、この振幅特性は、「０Ｈｚ」近傍の振幅利得が比較的低い。これは、非線形歪み成分は中心周波数近傍では振幅変動が小さいことを考慮したものである。 FIG. 7 a is a diagram showing the amplitude characteristics of the low-pass filter 351. This amplitude characteristic has a large amplitude gain in the low frequency range from the vicinity of the center frequency “0 Hz” of the differential signal to the vicinity of “−fs / 2”. For this reason, the differential signal after passing through the low-pass filter 351 is a signal composed of frequency components in the low-frequency range among the frequency components of the differential signal. In addition, this amplitude characteristic has a relatively low amplitude gain in the vicinity of “0 Hz”. This is because the non-linear distortion component has a small amplitude fluctuation in the vicinity of the center frequency.
　図７ｂは、高域通過フィルタ３５２の振幅特性を示す図である。この振幅特性は、差分信号の中心周波数「０Ｈｚ」近傍から「ｆｓ／２」近傍の高域の周波数範囲において振幅利得が大きい。このため、高域通過フィルタ３５２の通過後の差分信号は、差分信号の周波数成分のうち、高域の周波数範囲の周波数成分からなる信号となる。また、この振幅特性は、「０Ｈｚ」近傍の振幅利得が比較的低い。これは、非線形歪み成分の中心周波数近傍では振幅変動が小さいことを考慮したものである。 FIG. 7 b is a diagram showing the amplitude characteristics of the high-pass filter 352. This amplitude characteristic has a large amplitude gain in the high frequency range from the vicinity of the center frequency “0 Hz” of the difference signal to the vicinity of “fs / 2”. For this reason, the differential signal after passing through the high-pass filter 352 is a signal composed of frequency components in the high-frequency range among the frequency components of the differential signal. In addition, this amplitude characteristic has a relatively low amplitude gain in the vicinity of “0 Hz”. This is because the amplitude fluctuation is small in the vicinity of the center frequency of the nonlinear distortion component.
　このように、低域通過フィルタ３５１および高域通過フィルタ３５２における差分信号の中心周波数近傍における振幅利得を低く設定することによって、非線形歪み成分の周波数特性を適切に補正することができるようになる。 Thus, by setting the amplitude gain in the vicinity of the center frequency of the differential signal in the low-pass filter 351 and the high-pass filter 352 to be low, the frequency characteristic of the nonlinear distortion component can be appropriately corrected.
　次に、周波数特性補正部３００により生成される歪抑制送信信号の振幅特性について図面を参照して説明する。 Next, the amplitude characteristic of the distortion-suppressed transmission signal generated by the frequency characteristic correction unit 300 will be described with reference to the drawings.
　図８ａおよび図８ｂは、周波数特性補正部３００に供給される送信信号および歪抑制送信信号の振幅特性の一例を示す図である。この例では、縦軸を、デシベル（ｄＢ）単位により表わされた振幅とし、横軸を周波数とする。 8a and 8b are diagrams illustrating an example of amplitude characteristics of a transmission signal and a distortion-suppressed transmission signal supplied to the frequency characteristic correction unit 300. FIG. In this example, the vertical axis is the amplitude expressed in decibel (dB) units, and the horizontal axis is the frequency.
　図８ａは、入力端子１０１から信号線１０９を介して供給される送信信号の振幅特性１０２を示す。送信信号の振幅特性１０２は、中心周波数が「０Ｈｚ」であり、周波数帯域幅ＢＷの波形を示す。 FIG. 8 a shows the amplitude characteristic 102 of the transmission signal supplied from the input terminal 101 via the signal line 109. The amplitude characteristic 102 of the transmission signal indicates a waveform having a center frequency of “0 Hz” and a frequency bandwidth BW.
　図８ｂは、乗算部２３０から信号線２３９を介して出力される歪抑制送信信号の振幅特性１３１を示す。振幅特性１３１には、抑制係数抽出部２２０からの抑制係数が、送信信号に乗算されることによって生成された抑制成分１３２が含まれる。 FIG. 8 b shows the amplitude characteristic 131 of the distortion-suppressed transmission signal output from the multiplier 230 via the signal line 239. The amplitude characteristic 131 includes a suppression component 132 generated by multiplying the transmission signal by the suppression coefficient from the suppression coefficient extraction unit 220.
　図９ａ～図９ｄは、図８ａおよび図８ｂに示された送信信号１０２および歪抑制送信信号１３１が周波数特性補正部３００に供給された場合における周波数特性補正部３００の出力信号の振幅特性の例を示す図である。この例では、低域補正係数および高域補正係数の組合せのうち、代表的な４つのケースの例について簡単に説明する。 9a to 9d show examples of amplitude characteristics of the output signal of the frequency characteristic correction unit 300 when the transmission signal 102 and the distortion suppression transmission signal 131 shown in FIGS. 8a and 8b are supplied to the frequency characteristic correction unit 300. FIG. FIG. In this example, a representative example of four cases among combinations of a low-frequency correction coefficient and a high-frequency correction coefficient will be briefly described.
　図９ａは、増幅部１４０の周波数特性によって非線形歪み成分の低域側が低く、高域側が高くなる場合における出力信号の振幅特性３０１を示す。振幅特性３０１における抑制成分３７１は、乗算部２３０により生成される抑制成分１３２に比べて、低域側が抑圧され、高域側が強調される。この場合、補正係数保持部３２０には、負の低域補正係数と、正の高域補正係数と、が保持されている。 FIG. 9 a shows the amplitude characteristic 301 of the output signal when the low frequency side of the nonlinear distortion component is low and the high frequency side is high due to the frequency characteristic of the amplification unit 140. The suppression component 371 in the amplitude characteristic 301 is suppressed on the low frequency side and emphasized on the high frequency side compared to the suppression component 132 generated by the multiplication unit 230. In this case, the correction coefficient holding unit 320 holds a negative low-frequency correction coefficient and a positive high-frequency correction coefficient.
　図９ｂは、増幅部１４０の周波数特性によって非線形歪み成分の低域側が高く、高域側が低くなる場合における出力信号の振幅特性３０２を示す。振幅特性３０２における抑制成分３７２は、抑制成分１３２に比べて、低域側が強調され、高域側が抑圧される。この場合、補正係数保持部３２０には、正の低域補正係数と、負の高域補正係数と、が保持されている。 FIG. 9 b shows the amplitude characteristic 302 of the output signal when the low frequency side of the nonlinear distortion component is high and the high frequency side is low due to the frequency characteristic of the amplification unit 140. The suppression component 372 in the amplitude characteristic 302 is emphasized on the low frequency side and suppressed on the high frequency side compared to the suppression component 132. In this case, the correction coefficient holding unit 320 holds a positive low-frequency correction coefficient and a negative high-frequency correction coefficient.
　図９ｃは、増幅部１４０の周波数特性によって非線形歪み成分の低域側および高域側が高くなる場合における出力信号の振幅特性３０３を示す。振幅特性３０３における抑制成分３７３は、乗算部２３０により生成される抑制成分１３２に比べて、低域側および高域側が強調される。この場合、補正係数保持部３２０には、正の低域補正係数と、正の高域補正係数と、が保持されている。 FIG. 9c shows the amplitude characteristic 303 of the output signal when the low frequency side and the high frequency side of the nonlinear distortion component are increased by the frequency characteristic of the amplification unit 140. The suppression component 373 in the amplitude characteristic 303 is emphasized on the low frequency side and the high frequency side compared to the suppression component 132 generated by the multiplication unit 230. In this case, the correction coefficient holding unit 320 holds a positive low-frequency correction coefficient and a positive high-frequency correction coefficient.
　図９ｄは、増幅部１４０の周波数特性によって非線形歪み成分の低域側および高域側が低くなる場合における出力信号の振幅特性３０４を示す。振幅特性３０４における抑制成分３７４は、抑制成分１３２に比べて、低域側および高域側が抑圧される。この場合には、補正係数保持部３２０には、負の低域補正係数と、負の高域補正係数と、が保持されている。 FIG. 9d shows the amplitude characteristic 304 of the output signal when the low frequency side and the high frequency side of the nonlinear distortion component are lowered by the frequency characteristic of the amplification unit 140. The suppression component 374 in the amplitude characteristic 304 is suppressed on the low frequency side and the high frequency side compared to the suppression component 132. In this case, the correction coefficient holding unit 320 holds a negative low-frequency correction coefficient and a negative high-frequency correction coefficient.
　このように、補正係数設定部３１０が、増幅部１４０の周波数特性に応じて、低域補正係数および高域補正係数をそれぞれ設定することによって、増幅装置１００は、抑制成分１３２の周波数特性を制御することができる。 Thus, the correction coefficient setting unit 310, in accordance with the frequency characteristic of the amplification section 140, by setting the low-range correction coefficient and high correction coefficients respectively, amplifier 100 controls the frequency characteristic of inhibiting component 132 can do.
　図１０は、増幅装置１００における歪み補償方法の処理手順例を示すフローチャートである。 FIG. 10 is a flowchart illustrating an example of a processing procedure of a distortion compensation method in the amplification device 100.
　まず、抑制係数抽出部２２０は、振幅算出部２１０からの送信信号の振幅の大きさに基づいて、抑制係数保持部２７０に保持された抑制係数を抽出する（ステップＳ９０１）。 First, the suppression coefficient extracting unit 220, based on the magnitude of the amplitude of the transmission signal from the amplitude calculating unit 210, extracts the suppression coefficient held in the suppression coefficient holding unit 270 (step S901).
　この後、乗算部２３０は、入力端子１０１からの送信信号と、抑制係数抽出部２２０により抽出された抑制係数と、に基づいて、歪抑制送信信号を生成する（ステップＳ９０２）。そして、加算器３４０は、乗算部２３０の出力である歪抑制送信信号から、送信信号を減算することによって、抑制成分からなる差分信号を生成する（ステップＳ９０３）。 Thereafter, multiplier 230, a transmission signal from the input terminal 101, a suppression coefficient extracted by suppression factor extraction unit 220, on the basis, to generate a distortion suppression transmission signal (step S902). Then, the adder 340 generates a differential signal composed of suppression components by subtracting the transmission signal from the distortion suppression transmission signal that is the output of the multiplication unit 230 (step S903).
　そして、低域通過フィルタ３５１は、加算器３４０からの差分信号における低域の周波数成分を抽出して、その抽出された信号を、低域の抽出信号として出力する。これとともに、高域通過フィルタ３５２は、加算器３４０からの差分信号における高域の周波数成分を抽出して、その抽出された信号を、高域の抽出信号として出力する（ステップＳ９０４）。 The low-pass filter 351 extracts a low-frequency component in the difference signal from the adder 340 and outputs the extracted signal as a low-frequency extraction signal. At the same time, the high-pass filter 352 extracts a high-frequency component from the difference signal from the adder 340 and outputs the extracted signal as a high-frequency extraction signal (step S904).
　この後、乗算器３６１は、低域通過フィルタからの低域の抽出信号と、補正係数保持部３２０に保持された低域の補正係数とに基づいて、低域の補正信号を生成する。これとともに、乗算器３６２は、高域通過フィルタからの高域の抽出信号と、補正係数保持部３２０に保持された高域の補正係数とに基づいて、高域の補正信号を生成する（ステップＳ９０５）。 Thereafter, the multiplier 361, based on the extracted signal of low frequency from the low-pass filter, and the correction coefficient of low frequency held in the correction coefficient storing unit 320, generates a correction signal of low frequency. At the same time, the multiplier 362 generates a high-frequency correction signal based on the high-frequency extracted signal from the high-pass filter and the high-frequency correction coefficient held in the correction coefficient holding unit 320 (step). S905).
　そして、加算部３７０は、乗算器３６１および３６２からの低域および高域の補正信号を、歪抑制送信信号に加算することによって、新たな歪抑制送信信号を生成して（ステップＳ９０６）、歪み補償方法の処理手順が終了する。 Adder 370 then generates a new distortion-suppressed transmission signal by adding the low-frequency and high-frequency correction signals from multipliers 361 and 362 to the distortion-suppressed transmission signal (step S906). processing procedure of compensation method ends.
　このように、本実施形態によれば、周波数特性補正部３００は、補正係数設定部３１０により設定された補正係数に基づいて歪抑制送信信号における抑制成分の周波数特性を補正することができる。これにより、歪み補償回路２００は、増幅部１４０の出力信号に含まれる非線形歪み成分を低減することができる。すなわち、周波数特性補正部３００は、増幅部１４０のメモリ効果に起因する歪み成分を抑制することができる。 Thus, according to this embodiment, the frequency characteristic correcting unit 300 can correct the frequency characteristic of inhibiting component in the distortion suppressing transmission signal based on the correction coefficient set by the correction coefficient setting unit 310. Thereby, the distortion compensation circuit 200 can reduce the nonlinear distortion component included in the output signal of the amplification unit 140. That is, the frequency characteristic correction unit 300 can suppress distortion components due to the memory effect of the amplification unit 140.
　本実施形態では、抽出部３５０が、送信信号と歪抑制送信信号との差分信号の周波数成分のうち、複数の周波数範囲の各々に対応する周波数成分を抽出信号として周波数範囲ごとに抽出する。そして、乗算部３６０が、周波数範囲ごとに、補正係数保持部３２０からの補正係数と、抽出部３５０からの抽出信号と、に基づいて、周波数範囲ごとの補正信号を生成する。これにより、歪抑制送信信号における抑制成分の周波数特性を周波数範囲ごとに制御することができる。 In this embodiment, the extraction unit 350 extracts, for each frequency range, frequency components corresponding to each of a plurality of frequency ranges from among the frequency components of the difference signal between the transmission signal and the distortion-suppressed transmission signal. Then, the multiplication unit 360 generates a correction signal for each frequency range based on the correction coefficient from the correction coefficient holding unit 320 and the extraction signal from the extraction unit 350 for each frequency range. Thereby, the frequency characteristic of the suppression component in a distortion suppression transmission signal can be controlled for every frequency range.
　また、本実施形態では、周波数特性補正部３００は、低域通過フィルタ３５１および高域通過フィルタ３５２と、乗算器３６１および３６２とによって、抑制成分における低域および高域の周波数特性を独立して制御する。このように２つの帯域のみを制御するだけでも、メモリ効果による非線形歪み成分の周波数変動は急峻でないため、増幅部１４０の出力における残留成分を十分に取り除くことができる。これにより、歪み補償回路２００は、最小限のフィルタ数により抑制成分の周波数特性の補正を行うことができるため、歪み補償回路２００の回路規模を抑制することができる。 In the present embodiment, the frequency characteristic correction unit 300 uses the low-pass filter 351, the high-pass filter 352, and the multipliers 361 and 362 to independently reduce the low-frequency and high-frequency characteristics in the suppression component. Control. Thus alone control only two bands, since the frequency variation of the nonlinear distortion component caused by the memory effect is not steep, it is possible to remove residual components at the output of the amplifier 140 adequately. Thereby, the distortion compensation circuit 200 can correct the frequency characteristic of the suppression component with the minimum number of filters, and thus the circuit scale of the distortion compensation circuit 200 can be suppressed.
　さらに、増幅装置１００の使用者は、２つの補正係数のみを調整するだけで、歪抑制送信信号に含まれる抑制成分の周波数特性を制御することができる。このため、周波数特性補正部３００に代えてディジタルフィルタを設けて、多数のフィルタ係数を直接設定する場合に比べて、使用者は、抑制成分の周波数特性を簡便に制御することができる。 Furthermore, the user of the amplifying apparatus 100 can control the frequency characteristics of the suppression component included in the distortion-suppressed transmission signal only by adjusting the two correction coefficients. Therefore, by providing a digital filter instead of the frequency characteristic correcting unit 300, as compared with the case of setting the number of filter coefficients directly, the user can conveniently control the frequency characteristic of inhibiting component.
　また、歪み補償回路２００は、補正係数の設定ステップ幅を小さくすることによって、予め定められた周波数特性を選択してディジタルフィルタに設定する場合に比べて、抑制成分の周波数特性を精度良く制御することができる。 In addition, the distortion compensation circuit 200 controls the frequency characteristic of the suppression component with high accuracy by reducing the setting step width of the correction coefficient as compared with the case where a predetermined frequency characteristic is selected and set in the digital filter. be able to.
　また、本実施形態では、周波数特性補正部３００は、加算器３４０が送信信号と歪抑制送信信号との差分信号を生成することによって、抑制成分に基づいて補正信号を生成することができる。これより、周波数特性補正部３００は、非線形歪み成分の大きさに応じて増幅部１４０の周波数特性の影響度合いが変化する非線形歪み成分の周波数変動を、適切に抑制することができる。すなわち、周波数特性補正部３００は、乗算部２３０からの歪抑制送信信号に基づいて周波数特性を補正する場合に比べて、増幅部１４０の出力信号に含まれる歪み成分をより適切に軽減することができる。 Further, in the present embodiment, the frequency characteristic correcting unit 300 can generate a correction signal based on the suppression component by causing the adder 340 to generate a differential signal between the transmission signal and the distortion suppression transmission signal. Thus, the frequency characteristic correction unit 300 can appropriately suppress the frequency fluctuation of the nonlinear distortion component in which the degree of influence of the frequency characteristic of the amplification unit 140 changes according to the magnitude of the nonlinear distortion component. That is, the frequency characteristic correcting unit 300 can more appropriately reduce the distortion component included in the output signal of the amplifying unit 140 as compared with the case where the frequency characteristic is corrected based on the distortion suppression transmission signal from the multiplying unit 230. it can.
　また、本実施形態では、増幅部１４０の周波数特性に起因する非線形歪み成分の周波数変動の特性を考慮して、低域通過フィルタ３５１および高域通過フィルタ３５２における差分信号の中心周波数近傍の振幅特性を低く抑えている。このため、周波数変動の小さい抑制成分の中心周波数近傍に比べて、低域通過フィルタ３５１または高域通過フィルタ３５２の周波数範囲の中程の周波数帯域の振幅の補正量を大きくすることがきる。これにより、２つのフィルタのみの構成であっても、増幅部１４０の有する周波数特性に起因する歪み成分を適切に抑制することができる。 Further, in the present embodiment, in consideration of the frequency variation characteristic of the nonlinear distortion component caused by the frequency characteristic of the amplification unit 140, the amplitude characteristic near the center frequency of the difference signal in the low-pass filter 351 and the high-pass filter 352. Is kept low. For this reason, it is possible to increase the correction amount of the amplitude of the frequency band in the middle of the frequency range of the low-pass filter 351 or the high-pass filter 352 as compared with the vicinity of the center frequency of the suppression component with small frequency fluctuation. Thereby, even if it is the structure of only two filters, the distortion component resulting from the frequency characteristic which the amplifier 140 has can be suppressed appropriately.
　なお、実施形態では、増幅装置１００が、使用者の操作に基づいて補正係数保持部３２０に補正係数を設定する例について説明したが、増幅装置１００が、送信信号と、帰還信号とに基づいて、補正係数を生成するようにしてもよい。 In the embodiment, the example in which the amplifying apparatus 100 sets the correction coefficient in the correction coefficient holding unit 320 based on the operation of the user has been described. However, the amplifying apparatus 100 is based on the transmission signal and the feedback signal. A correction coefficient may be generated.
　以上説明した実施形態において、図示した構成は単なる一例であって、本発明はその構成に限定されるものではない。 In the embodiment described above, the illustrated configuration is merely an example, and the present invention is not limited to the configuration.
　この出願は、２００９年１１月１０日に出願された日本出願特願２００９－２５６９５８を基礎とする優先権を主張し、その開示の全てをここに取り込む。 This application claims priority based on Japanese Patent Application No. 2009-256958 filed on November 10, 2009, the entire disclosure of which is incorporated herein.
　１００　増幅装置
　１１０　変調部
　１２０　Ｄ／Ａ変換部
　１３０、１７０、２３０、３６０　乗算部
　１４０　増幅部
　１５０　方向性結合器
　１６０　周波数発振部
　１８０　Ａ／Ｄ変換部
　１９０　復調部
　２００　歪み補償回路
　２１０　振幅算出部
　２２０　歪抑制係数抽出部
　２４０　帰還信号保持部
　２５０　送信信号保持部
　２６０　抑制係数算出部
　２７０　抑制係数保持部
　３００　周波数特性補正部
　３１０　補正係数設定部
　３２０　補正係数保持部
　３４０　加算器
　３５０　抽出部
　３５１　低域通過フィルタ
　３５２　高域通過フィルタ
　３６１、３６２　乗算器
　３７０　加算部 DESCRIPTION OF SYMBOLS 100 Amplifier 110 Modulator 120 D / A converter 130, 170, 230, 360 Multiplier 140 Amplifier 150 Directional coupler 160 Frequency oscillator 180 A / D converter 190 Demodulator 200 Distortion compensation circuit 210 Amplitude calculator 220 distortion suppression coefficient extraction unit 240 feedback signal holding unit 250 transmission signal holding unit 260 suppression coefficient calculation unit 270 suppression coefficient holding unit 300 frequency characteristic correction unit 310 correction coefficient setting unit 320 correction coefficient holding unit 340 adder 350 extraction unit 351 low range Pass filter 352 High-pass filter 361, 362 Multiplier 370 Adder

Claims (6)

  1. 　電力を増幅する増幅手段に供給される増幅対象信号を生成するための入力信号を受け付ける入力端子と、
    　前記増幅手段の有する入出力特性の非線形性に起因する前記増幅手段の出力信号の歪み成分を抑制するための抑制係数を前記入力信号に乗算することによって歪抑制入力信号を生成する乗算手段と、
    　前記入力信号と前記歪抑制入力信号との差分信号の周波数成分のうち複数の周波数範囲の各々に対応する周波数成分を前記周波数範囲ごとに抽出信号として抽出する抽出手段と、
    　前記増幅手段の有する周波数特性に起因する前記歪み成分の周波数特性の変化を補正するための補正係数を前記周波数範囲ごとに保持する補正係数保持手段と、
    　前記周波数範囲ごとに前記補正係数を前記抽出信号に乗算することによって前記周波数範囲ごとの補正信号を生成する補正信号生成手段と、
    　前記周波数範囲ごとの補正信号と前記歪抑制入力信号とに基づいて、前記増幅対象信号を生成する増幅対象信号生成手段と、を含む歪み補償回路。     An input terminal for receiving an input signal for generating a signal to be amplified to be supplied to an amplifying means for amplifying power;
    Multiplication means for generating a distortion suppression input signal by multiplying the input signal by a suppression coefficient for suppressing distortion components of the output signal of the amplification means due to nonlinearity of the input / output characteristics of the amplification means;
    Extraction means for extracting frequency components corresponding to each of a plurality of frequency ranges among the frequency components of the difference signal between the input signal and the distortion suppression input signal as an extraction signal for each frequency range;
    Correction coefficient holding means for holding, for each frequency range, a correction coefficient for correcting a change in frequency characteristic of the distortion component caused by the frequency characteristic of the amplification means;
    Correction signal generation means for generating a correction signal for each frequency range by multiplying the extraction signal by the correction coefficient for each frequency range;
    A distortion compensation circuit including amplification target signal generation means for generating the amplification target signal based on the correction signal for each frequency range and the distortion suppression input signal.
  2. 　前記抽出手段は、前記差分信号の周波数成分のうち前記差分信号の全周波数範囲の中程よりも低い周波数範囲と、他の周波数範囲と、の各々に対応する周波数成分を前記周波数範囲ごとに前記抽出信号として抽出し、
    　前記増幅対象信号生成手段は、前記低い周波数範囲および前記他の周波数範囲の各々に対応する前記補正信号と、前記歪抑制入力信号と、を加算することによって前記増幅対象信号を生成する、請求項１記載の歪み補償回路。     The extraction means includes, for each frequency range, a frequency component corresponding to each of a frequency range lower than the middle of the entire frequency range of the difference signal among the frequency components of the difference signal, for each frequency range. Extract as an extraction signal,
    The amplification target signal generation unit generates the amplification target signal by adding the correction signal corresponding to each of the low frequency range and the other frequency range and the distortion suppression input signal. The distortion compensation circuit according to 1.
  3. 　電力の入出力特性に非線形性を有し、かつ、周波数特性を有する増幅手段を備え、入力信号を増幅する増幅装置であって、
    　前記増幅手段の有する非線形性に起因する前記増幅手段の出力信号の歪み成分を抑制するための抑制係数と、前記入力信号と、を乗算することによって歪抑制入力信号を生成する乗算手段と、
    　前記入力信号と前記歪抑制入力信号との差分信号の周波数成分のうち複数の周波数範囲の各々に対応する周波数成分を前記周波数範囲ごとに抽出信号として抽出する抽出手段と、
    　前記増幅手段の有する周波数特性に起因する前記歪み成分の周波数特性の変化を補正するための補正係数を前記周波数範囲ごとに保持する補正係数保持手段と、
    　前記周波数範囲ごとに前記補正係数を前記抽出信号に乗算することによって前記周波数範囲ごとの補正信号を生成する補正信号生成手段と、
    　前記周波数範囲ごとの補正信号と、前記歪抑制入力信号と、に基づいて、増幅対象信号を生成する増幅対象信号生成手段と、を含み、
    　前記増幅手段は、前記増幅対象信号を増幅する、増幅装置。     An amplifying apparatus that has nonlinearity in input / output characteristics of power and includes an amplifying means having frequency characteristics, and amplifies an input signal,
    Multiplication means for generating a distortion-suppressed input signal by multiplying the input signal by a suppression coefficient for suppressing a distortion component of the output signal of the amplifying means due to the nonlinearity of the amplifying means;
    Extraction means for extracting frequency components corresponding to each of a plurality of frequency ranges among the frequency components of the difference signal between the input signal and the distortion suppression input signal as an extraction signal for each frequency range;
    Correction coefficient holding means for holding, for each frequency range, a correction coefficient for correcting a change in frequency characteristic of the distortion component caused by the frequency characteristic of the amplification means;
    Correction signal generation means for generating a correction signal for each frequency range by multiplying the extraction signal by the correction coefficient for each frequency range;
    Amplifying target signal generating means for generating a target signal to be amplified based on the correction signal for each frequency range and the distortion suppression input signal,
    The amplifying device amplifies the amplification target signal.
  4. 　前記抽出手段は、前記差分信号の周波数成分のうち前記差分信号の全周波数範囲の中程よりも低い周波数範囲と、他の周波数範囲と、の各々に対応する周波数成分を前記周波数範囲ごとに前記抽出信号として抽出し、
    　前記増幅対象信号生成手段は、前記低い周波数範囲および前記他の周波数範囲の各々に対応する前記補正信号と、前記歪抑制入力信号と、を加算することによって前記増幅対象信号を生成する、請求項３記載の増幅装置。     The extraction means includes, for each frequency range, a frequency component corresponding to each of a frequency range lower than the middle of the entire frequency range of the difference signal among the frequency components of the difference signal, for each frequency range. Extract as an extraction signal,
    The amplification target signal generation unit generates the amplification target signal by adding the correction signal corresponding to each of the low frequency range and the other frequency range and the distortion suppression input signal. 3. The amplification device according to 3.
  5. 　電力を増幅する増幅手段に供給される増幅対象信号を生成するための入力信号を受け付ける入力端子と、前記増幅手段の有する入出力特性の非線形性に起因する前記増幅手段の出力信号の歪み成分を抑制するための抑制係数を保持する抑制係数保持手段と、前記増幅手段の有する周波数特性に起因する前記歪み成分の周波数特性の変化を補正するための補正係数を複数の周波数範囲ごとに保持する補正係数保持手段と、を含む歪み補償回路における歪み補償方法であって、
    　前記入力信号に前記抑制係数を乗算することによって歪抑制入力信号を生成し、
    　前記入力信号と前記歪抑制入力信号との差分信号の周波数成分のうち前記周波数範囲の各々に対応する周波数成分を前記周波数範囲ごとに抽出信号として抽出し、
    　前記周波数範囲ごとに前記補正係数を前記抽出信号に乗算することによって前記周波数範囲ごとの補正信号を生成し、
    　前記周波数範囲ごとの前記補正信号と、前記歪抑制入力信号と、基づいて、前記増幅対象信号を生成する、歪み補償方法。     An input terminal for receiving an input signal for generating an amplification target signal to be supplied to an amplification means for amplifying power, and a distortion component of the output signal of the amplification means due to nonlinearity of input / output characteristics of the amplification means A suppression coefficient holding unit that holds a suppression coefficient for suppression, and a correction that holds a correction coefficient for correcting a change in frequency characteristic of the distortion component caused by the frequency characteristic of the amplification unit for each of a plurality of frequency ranges. A distortion compensation method in a distortion compensation circuit including coefficient holding means,
    Generating a distortion suppression input signal by multiplying the input signal by the suppression coefficient;
    The frequency component corresponding to each of the frequency ranges among the frequency components of the difference signal between the input signal and the distortion suppression input signal is extracted as an extraction signal for each frequency range,
    Generating a correction signal for each frequency range by multiplying the extracted signal by the correction coefficient for each frequency range;
    A distortion compensation method for generating the amplification target signal based on the correction signal for each frequency range and the distortion suppression input signal.
  6. 　前記周波数範囲の各々に対応する周波数成分を前記周波数範囲ごとに抽出信号として抽出することは、
    　前記差分信号の周波数成分のうち前記差分信号の全周波数範囲の中程よりも低い周波数範囲と、他の周波数範囲と、の各々に対応する周波数成分を前記周波数範囲ごとに前記抽出信号として抽出することを含み、
    　前記増幅対象信号を生成することは、
    　前記低い周波数範囲および前記他の周波数範囲の各々に対応する前記補正信号と、前記歪抑制入力信号と、を加算することによって前記増幅対象信号を生成することを含む、請求項５記載の歪み補償方法。     Extracting a frequency component corresponding to each of the frequency ranges as an extraction signal for each frequency range,
    Of the frequency components of the differential signal, the frequency components corresponding to each of the frequency range lower than the middle of the entire frequency range of the differential signal and the other frequency ranges are extracted as the extraction signal for each frequency range. Including
    Generating the signal to be amplified is
    The distortion compensation according to claim 5, further comprising: generating the amplification target signal by adding the correction signal corresponding to each of the low frequency range and the other frequency range and the distortion suppression input signal. Method.
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