WO2007020711A1 - Dcオフセット補正装置及びその方法 - Google Patents
Dcオフセット補正装置及びその方法 Download PDFInfo
- Publication number
- WO2007020711A1 WO2007020711A1 PCT/JP2005/015164 JP2005015164W WO2007020711A1 WO 2007020711 A1 WO2007020711 A1 WO 2007020711A1 JP 2005015164 W JP2005015164 W JP 2005015164W WO 2007020711 A1 WO2007020711 A1 WO 2007020711A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- signal
- offset
- state
- offset correction
- transmission
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/18—Phase-modulated carrier systems, i.e. using phase-shift keying
- H04L27/20—Modulator circuits; Transmitter circuits
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/06—Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection
- H04L25/061—Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection providing hard decisions only; arrangements for tracking or suppressing unwanted low frequency components, e.g. removal of dc offset
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/10—Calibration or testing
- H03M1/1009—Calibration
- H03M1/1014—Calibration at one point of the transfer characteristic, i.e. by adjusting a single reference value, e.g. bias or gain error
- H03M1/1019—Calibration at one point of the transfer characteristic, i.e. by adjusting a single reference value, e.g. bias or gain error by storing a corrected or correction value in a digital look-up table
-
- 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
- H04B1/06—Receivers
- H04B1/16—Circuits
-
- 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
- H04B1/06—Receivers
- H04B1/16—Circuits
- H04B1/30—Circuits for homodyne or synchrodyne receivers
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/06—Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
-
- 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
- H04L27/362—Modulation using more than one carrier, e.g. with quadrature carriers, separately amplitude modulated
- H04L27/364—Arrangements for overcoming imperfections in the modulator, e.g. quadrature error or unbalanced I and Q levels
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/66—Digital/analogue converters
Definitions
- the present invention relates to an apparatus and method for correcting a DC component generated by a quadrature modulator in a wireless communication apparatus.
- FIG. 1 is a diagram for explaining a local leak.
- a local leak occurs due to a direct current component (DC offset) generated in a DZA converter or modulator. Since this local leak becomes an unnecessary wave, the local leak must be reduced in order to realize high-quality communication.
- a function DC offset correction circuit
- the DC offset correction circuit parameters can be updated adaptively during wireless communication device operation. It is desirable to cancel. Therefore, the CPU calculates the DC component using the reference signal data or feedback signal data and adaptively updates the parameters of the DC offset correction circuit to reduce local leaks even if the temperature or IQ amplitude value changes. The device to be realized is realized.
- FIG. 2 is a diagram for explaining a reference signal type DC offset correction method.
- a feedback signal obtained by demodulating the output of the amplifier into an IQ signal through a feedback circuit and a reference signal that is a baseband signal before modulation are used.
- the feedback signal power is also subtracted from the reference signal, and using the error signal obtained by extracting only the DC offset component of the transmission signal, the anti-phase parameter is calculated and the DC offset correction circuit parameter is updated to remove the DC offset. I do.
- FIG. 3 is a diagram for explaining a feedback signal type DC offset correction method.
- the DC offset is corrected using only the feedback signal.
- the CPU estimates the DC offset vector direction and cancels the DC offset by setting a parameter in the DC offset correction circuit that takes an arbitrary amplitude in the opposite direction.
- the frequency phase used in the feedback circuit changes due to the rotation of the local phase, causing a deviation between the vector direction of the DC offset estimated by the CPU and the actual vector direction. Therefore, the CPU performs arbitrary corrections, investigates how the local phase rotation amount affects the feedback signal, and estimates the vector direction of the DC offset after taking that value into consideration.
- Fig. 3 (a) shows a DC vector obtained by adding a DC offset to the baseband signal vector.
- Figure 3 (b) shows the transmitted signal vector (RxDC vector) with the phase rotation ⁇ added to the DC vector.
- the correction vector that cancels the RxDC vector is generated by rotating the RxDC vector by 180 ° and multiplying it by an arbitrary constant, as shown in Fig. 3 (c).
- the TxDC vector is obtained as a result of adding the correction vector to the DC vector.
- the vector rotated by phase ⁇ is the second RxDC vector.
- the second RxDC vector is a vector after a correction vector is added to the baseband signal, modulated after DZA conversion, and fed back. Therefore, the difference between the RxDC vector in FIG. 3 (b) and the second RxDC vector in FIG. 3 (e) is a vector obtained by phase rotation of the correction vector. Therefore, the phase rotation amount ⁇ is obtained by comparing this difference vector with the first correction vector. Therefore, the correction
- a correction vector with phase correction corresponding to the amount of phase rotation is stored in the baseband signal. This compensates for the DC offset. After that, if the magnitude of the correction vector is changed sequentially so that the signal points are distributed around the original point on the IQ plane, the DC offset is cancelled.
- the features of the reference signal type DC offset correction method include the following points.
- the DC offset is extracted from the error component of the reference signal and the feedback signal, the DC component can be extracted even if the DC offset frequency overlaps the carrier modulation band, so the correction accuracy is high.
- Patent Document 1 International Publication Number WO2005Z025167 A1 Publication
- Patent Document 2 International Publication Number WO2005Z025168 A1 Publication
- An object of the present invention is to provide a DC offset correction apparatus capable of appropriately performing DC offset correction even when correction is difficult with one DC offset correction method.
- the DC offset correction apparatus of the present invention provides a demodulated feedback signal by feeding back a reference signal having an appropriate delay to the baseband signal, and modulating the baseband signal and then amplifying the signal after amplification by an amplifier.
- a DC offset correction device that corrects the DC offset of the transmission signal by examining the reference signal,
- a signal state estimating means for estimating a state of a transmitted signal, a method of correcting a DC offset of the transmitted signal using only the feedback signal based on the estimation result of the signal state, the reference signal and the reference signal One of the methods for correcting the DC offset of the transmission signal using both of the feedback signals is selected, and DC offset correction means for correcting the DC offset of the transmission signal is provided.
- FIG. 1 is a diagram for explaining a local leak.
- FIG. 2 is a diagram for explaining a reference signal type DC offset correction method.
- FIG. 3 is a diagram illustrating a feedback signal type DC offset correction method.
- FIG. 4 is a diagram illustrating a configuration example of a DC offset correction circuit.
- FIG. 5 is a diagram showing a DC offset correction circuit.
- FIG. 6 is a flowchart showing a DC offset correction sequence according to the embodiment of the present invention.
- FIG. 7 is a diagram for explaining a signal state estimation method.
- FIG. 8 is a diagram showing a method for determining selection of a DC offset correction method.
- FIG. 9 is a flowchart (part 1) of processing executed by CPU 20.
- FIG. 10 is a flowchart (part 2) of processing executed by CPU 2O.
- feedback signal type DC offset correction and reference signal type DC offset correction are used as a method for performing DC offset correction.
- the signal pattern of the reference signal is analyzed, and a more suitable method is selected and corrected.
- the calculation of DC offset rarely occurs when the calculation results in an abnormal value due to the noise component being redundant in the data due to the characteristics of storing the instantaneous value in the memory and performing the calculation.
- limiter values are set for the calculated values to prevent parameter abnormal values from being set, thereby minimizing abnormal parameter values at the time of incorrect calculations.
- FIG. 4 is a diagram illustrating a configuration example of a DC offset correction circuit.
- the input signal which is a baseband signal, is delayed by the delay circuit 22 and then stored in the memory circuit 21.
- This signal is a reference signal.
- the input signal also has a distortion compensation circuit. After distortion compensation is performed by the path 10, DC offset correction processing is performed by the DC offset correction circuit 11, and then the digital signal is converted into an analog signal by the DZA converter 12 and modulated by the quadrature modulator 13.
- the local oscillator 15-1 supplies a carrier wave in quadrature modulation. Mainly through the DZA converter 12 and the quadrature modulator 13, the signal gets a DC offset.
- the output of the quadrature modulator 13 is amplified by the amplifier 14 and output.
- the output of the amplifier 14 is fed back, multiplied by the oscillation wave of the local oscillator 15-2 in the multiplier 16, and down-converted.
- the analog signal is converted into a digital signal by the AZD converter 17 and demodulated by the demodulator 18.
- the demodulated signal is stored in the memory circuit 19.
- the CPU 20 appropriately reads out the feedback signal and the reference signal from the memory circuits 19 and 21, processes them, obtains a DC offset correction vector, and supplies the DC offset correction vector 11 to the DC offset correction circuit 11.
- FIG. 5 is a diagram showing a DC offset correction circuit.
- xi is the input I signal to this circuit
- xq is the input Q signal to this circuit
- Xi is the output I signal of this circuit power
- Xq is the output Q signal from this circuit is there.
- FIG. 6 is a flowchart showing a DC offset correction sequence according to the embodiment of the present invention.
- step S10 the reference signal and the feedback signal are written in the memory circuits 21 and 19, respectively.
- step S11 the current signal state is estimated from the reference signal input data.
- step S12 a DC offset correction method is selected from the signal state estimated in step S11. In this embodiment, the difference between the feedback signal type DC offset correction method and the reference signal type DC offset correction method is selected.
- step S13 a correction value is calculated.In step S14, if the calculated value is equal to or greater than the limiter value, the calculated value is considered to be abnormal and the calculated value is ignored and the limiter value is regarded as the correction value. To do. If the calculated value is less than the limiter value, it is calculated The corrected value is used as the correction value. In step S15, the corrected parameter value is updated and set.
- FIG. 7 is a diagram for explaining a signal state estimation method.
- the signal state is estimated by the CPU 20 examining the reference signal stored in the memory circuit 21.
- the power value which is the square sum of the I component XI and Q component Xq of the signal, is a constant value.
- the power value is observed for a predetermined time, and if the power value remains constant, it is determined that there is no modulation.
- the burst state of Fig. 7 (b) the data has a constant interval of 0 amplitude. Therefore, if 0 amplitude data continues over a certain number, it is determined as a burst state.
- the reference signal data is fixed at 0, so that it is determined that the wave-stopping state.
- FIG. 8 is a diagram showing a method for determining selection of the DC offset correction method.
- the reference signal type DC offset correction method when the feedback type DC offset correction method is used, if the local leak is hidden within the transmission frequency bandwidth of the carrier, the correction accuracy will drop, so the reference signal type DC Use the offset correction method.
- the unmodulated wave state if the feedback type DC offset correction method is used, if the carrier frequency and the local leak are the same frequency, the amplitude of the unmodulated carrier is corrected, so the reference signal type DC offset correction method is used. To do. In the burst state, the reference signal type DC offset correction method cannot perform phase adjustment at the point where the transmission data is 0 amplitude, and therefore cannot perform accurate correction. Therefore, the feedback type DC offset correction method is used in the burst state. Since there is no reference signal in the stopped state, the feedback type DC offset correction method is used.
- 9 and 10 are flowcharts of processing executed by the CPU 20.
- step S20 the reference signal and the feedback signal are written in the memory circuits 21 and 19, respectively.
- step S21 the I component of the reference signal is read from the memory circuit 21.
- step S22 the Q component of the reference signal is read from the memory circuit 21.
- step S23 the sum of squares of the read I component and Q component is calculated.
- step S24 the sum of squares is stored in the memory area of the memory circuit 21.
- step S25 it is determined whether or not all the reference signal data stored in the memory circuit 21 have been read. If the determination in step S25 is no, return to step S21 and repeat the process. If the determination in step S25 is Yes, the signal state is estimated from the calculated sum of squares in step S26.
- step S28 reference signal type DC offset correction is executed, a correction value is obtained, and the process proceeds to step S29.
- step S29 it is determined whether or not the correction value is larger than the limiter value. If the determination in step S29 is no, the process proceeds to step S31. If the determination in step S29 is yes, the correction value is replaced with the limiter value in step S30, and the process proceeds to step S31.
- step S31 the DC offset correction value correction value is updated. As a result, DC offset correction is executed with new correction.
- FIG. 10 is a flowchart showing details of the state estimation process of FIG.
- step S35 it is determined whether the amplitude of all signals is 0 or not by detecting the sum of squares. If the determination in step S35 is Yes, it is estimated that the wave is stopped. If the determination in step S35 is No, it is determined in step S36 whether the sum of squares is the same value for all signals. If the determination in step S36 is Yes, it is estimated that the state is an unmodulated wave state. If the determination in step S36 is No, it is determined in step S37 whether or not there is a predetermined number of zero amplitude states. If the determination in step S37 is yes, it is estimated that a burst state is present. If the determination in step S37 is No, the normal state is estimated.
Abstract
Description
Claims
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN200580051350XA CN101238643B (zh) | 2005-08-19 | 2005-08-19 | 直流偏移校正装置及其方法 |
PCT/JP2005/015164 WO2007020711A1 (ja) | 2005-08-19 | 2005-08-19 | Dcオフセット補正装置及びその方法 |
DE602005024058T DE602005024058D1 (de) | 2005-08-19 | 2005-08-19 | Gleichstrom-Offsetkorrektureinrichtung und Verfahren dafür |
KR1020087001928A KR100935793B1 (ko) | 2005-08-19 | 2005-08-19 | Dc 오프셋 보정 장치 및 그 방법 |
EP05772581A EP1916773B1 (en) | 2005-08-19 | 2005-08-19 | DC offset correction device and its method |
JP2007530893A JP4256446B2 (ja) | 2005-08-19 | 2005-08-19 | Dcオフセット補正装置及びその方法 |
US12/016,354 US7564921B2 (en) | 2005-08-19 | 2008-01-18 | DC offset correction apparatus and method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2005/015164 WO2007020711A1 (ja) | 2005-08-19 | 2005-08-19 | Dcオフセット補正装置及びその方法 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/016,354 Continuation US7564921B2 (en) | 2005-08-19 | 2008-01-18 | DC offset correction apparatus and method |
Publications (1)
Publication Number | Publication Date |
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WO2007020711A1 true WO2007020711A1 (ja) | 2007-02-22 |
Family
ID=37757383
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/JP2005/015164 WO2007020711A1 (ja) | 2005-08-19 | 2005-08-19 | Dcオフセット補正装置及びその方法 |
Country Status (7)
Country | Link |
---|---|
US (1) | US7564921B2 (ja) |
EP (1) | EP1916773B1 (ja) |
JP (1) | JP4256446B2 (ja) |
KR (1) | KR100935793B1 (ja) |
CN (1) | CN101238643B (ja) |
DE (1) | DE602005024058D1 (ja) |
WO (1) | WO2007020711A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009075144A1 (ja) * | 2007-12-10 | 2009-06-18 | Nec Corporation | 無線通信装置および直流オフセット調整方法 |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4256446B2 (ja) * | 2005-08-19 | 2009-04-22 | 富士通株式会社 | Dcオフセット補正装置及びその方法 |
JP2010054218A (ja) * | 2008-08-26 | 2010-03-11 | Toyota Central R&D Labs Inc | デジタル信号処理装置及びそれを有するフェーズドアレイレーダ |
KR101184861B1 (ko) | 2011-09-27 | 2012-09-20 | 한국전력공사 | 전력량계의 직류 오프셋 제거장치 및 방법 |
CN113595640B (zh) * | 2020-04-30 | 2023-06-27 | 华为技术有限公司 | 一种信号处理方法及装置 |
Citations (4)
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JP2001285387A (ja) * | 2000-01-28 | 2001-10-12 | Hitachi Kokusai Electric Inc | 負帰還回路を備えた電力増幅回路及び位相制御方法 |
JP2001339452A (ja) * | 2000-05-26 | 2001-12-07 | Hitachi Kokusai Electric Inc | 直交変調装置及び直交変調誤差検出方法 |
US20030174783A1 (en) | 2002-03-12 | 2003-09-18 | Mahibur Rahman | Self calibrating transmit path correction system |
WO2005025167A1 (ja) | 2003-09-05 | 2005-03-17 | Fujitsu Limited | オフセット補償装置 |
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US5959500A (en) * | 1998-01-26 | 1999-09-28 | Glenayre Electronics, Inc. | Model-based adaptive feedforward amplifier linearizer |
US5990734A (en) * | 1998-06-19 | 1999-11-23 | Datum Telegraphic Inc. | System and methods for stimulating and training a power amplifier during non-transmission events |
GB2354649A (en) * | 1999-09-22 | 2001-03-28 | Cadence Design Systems Inc | Method and apparatus for generating a modulated radio frequency output signal |
US6384677B2 (en) | 2000-01-28 | 2002-05-07 | Hitachi Kokusai Electric Inc. | Power amplifier having negative feedback circuit for transmitter |
US6560447B2 (en) * | 2001-03-05 | 2003-05-06 | Motorola, Inc. | DC offset correction scheme for wireless receivers |
JP4256446B2 (ja) * | 2005-08-19 | 2009-04-22 | 富士通株式会社 | Dcオフセット補正装置及びその方法 |
JP4758781B2 (ja) * | 2006-01-31 | 2011-08-31 | 富士通株式会社 | Dcオフセット補正装置及びその方法 |
-
2005
- 2005-08-19 JP JP2007530893A patent/JP4256446B2/ja not_active Expired - Fee Related
- 2005-08-19 CN CN200580051350XA patent/CN101238643B/zh not_active Expired - Fee Related
- 2005-08-19 KR KR1020087001928A patent/KR100935793B1/ko active IP Right Grant
- 2005-08-19 WO PCT/JP2005/015164 patent/WO2007020711A1/ja active Application Filing
- 2005-08-19 EP EP05772581A patent/EP1916773B1/en not_active Expired - Fee Related
- 2005-08-19 DE DE602005024058T patent/DE602005024058D1/de active Active
-
2008
- 2008-01-18 US US12/016,354 patent/US7564921B2/en active Active
Patent Citations (5)
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JP2001285387A (ja) * | 2000-01-28 | 2001-10-12 | Hitachi Kokusai Electric Inc | 負帰還回路を備えた電力増幅回路及び位相制御方法 |
JP2001339452A (ja) * | 2000-05-26 | 2001-12-07 | Hitachi Kokusai Electric Inc | 直交変調装置及び直交変調誤差検出方法 |
US20030174783A1 (en) | 2002-03-12 | 2003-09-18 | Mahibur Rahman | Self calibrating transmit path correction system |
WO2005025167A1 (ja) | 2003-09-05 | 2005-03-17 | Fujitsu Limited | オフセット補償装置 |
WO2005025168A1 (ja) | 2003-09-05 | 2005-03-17 | Fujitsu Limited | オフセット補償装置 |
Non-Patent Citations (1)
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2009075144A1 (ja) * | 2007-12-10 | 2009-06-18 | Nec Corporation | 無線通信装置および直流オフセット調整方法 |
JPWO2009075144A1 (ja) * | 2007-12-10 | 2011-04-28 | 日本電気株式会社 | 無線通信装置および直流オフセット調整方法 |
US8396433B2 (en) | 2007-12-10 | 2013-03-12 | Nec Corporation | Radio communication apparatus and DC offset adjustment method |
Also Published As
Publication number | Publication date |
---|---|
JPWO2007020711A1 (ja) | 2009-02-19 |
EP1916773A1 (en) | 2008-04-30 |
DE602005024058D1 (de) | 2010-11-18 |
US20080111723A1 (en) | 2008-05-15 |
CN101238643B (zh) | 2010-12-15 |
CN101238643A (zh) | 2008-08-06 |
EP1916773B1 (en) | 2010-10-06 |
US7564921B2 (en) | 2009-07-21 |
EP1916773A4 (en) | 2010-01-27 |
KR20080028961A (ko) | 2008-04-02 |
KR100935793B1 (ko) | 2010-01-06 |
JP4256446B2 (ja) | 2009-04-22 |
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