CN113452634A - Apparatus and method for non-linear distortion estimation and compensation in polar transmitter - Google Patents
Apparatus and method for non-linear distortion estimation and compensation in polar transmitter Download PDFInfo
- Publication number
- CN113452634A CN113452634A CN202010225181.3A CN202010225181A CN113452634A CN 113452634 A CN113452634 A CN 113452634A CN 202010225181 A CN202010225181 A CN 202010225181A CN 113452634 A CN113452634 A CN 113452634A
- Authority
- CN
- China
- Prior art keywords
- signal
- generate
- polar transmitter
- frequency
- unit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 25
- 238000012360 testing method Methods 0.000 claims abstract description 40
- 238000012545 processing Methods 0.000 claims abstract description 26
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 230000008569 process Effects 0.000 claims description 3
- 230000010355 oscillation Effects 0.000 claims description 2
- 230000006870 function Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 238000004891 communication Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 238000004590 computer program Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/38—Synchronous or start-stop systems, e.g. for Baudot code
- H04L25/40—Transmitting circuits; Receiving circuits
- H04L25/49—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems
Abstract
The invention relates to a device and a method for carrying out nonlinear distortion estimation and compensation in a polar coordinate transmitter. The invention discloses a device for distortion estimation and compensation of a polar transmitter, comprising: a mixing unit, a signal processing unit, an estimation unit and a compensation unit. The frequency mixing unit is used for mixing a test output signal of the polar coordinate transmitter with a frequency-down signal to generate a mixed signal. The signal processing unit is used for carrying out signal processing on the mixed signal to generate a processed signal. The estimation unit is used for carrying out distortion estimation according to the processed signal to generate a distortion estimation result. The compensation unit is used for carrying out predistortion compensation on the input signal of the polar coordinate transmitter according to the estimation result.
Description
Technical Field
The present invention relates to polar modulation communication systems, and more particularly, to an apparatus and method for non-linear distortion estimation and compensation in a polar transmitter.
Background
In a polar transmitter (polar transmitter), an in-phase/quadrature signal on an I/Q channel is converted into an amplitude and phase signal, and the two signals are combined by a power amplifier for transmission. The advantage of a transmitter of this architecture is that it can be implemented using all digital (all digital) circuitry, with particular advantages over transmitters implemented in analog circuitry. However, the power amplifier itself has a non-linear distortion characteristic, and thus, a degradation of communication quality may be caused. Fig. 1 shows nonlinear distortion caused by a power amplifier in a polar transmitter, which includes amplitude modulation to amplitude modulation (AM-AM) distortion and amplitude modulation to phase modulation (AM-PM) distortion. As shown, when the amplitude of the input signal is higher than a certain value, the previous linear relationship between the output amplitude and the input amplitude is lost. Similarly, the output phase is distorted after the amplitude of the input signal is higher than a certain value. These distortions are caused by poor non-linear characteristics of the power amplifier. Therefore, in order to improve the communication quality, it is necessary to provide a distortion estimation and compensation mechanism to solve the above problem.
Disclosure of Invention
The invention provides a distortion estimation and compensation device and a method for solving the problem of nonlinear distortion of a power amplifier in an existing polar coordinate transmitter. In the non-linear distortion estimation structure provided by the invention, a frequency reduction technique is utilized to enable an output signal of the power amplifier to be easily observed, and characteristics of amplitude modulation to amplitude modulation distortion, amplitude modulation to phase modulation distortion and the like of the power amplifier are estimated through a series of signal processing techniques. And then, pre-distortion compensation is carried out on the input signal of the polar coordinate transmitter through the distortion estimation result, so that the nonlinear defect of the power amplifier is overcome.
An embodiment of the present invention provides an apparatus for distortion estimation and compensation for a polar transmitter. The device comprises: a mixing unit, a signal processing unit, an estimation unit and a compensation unit. The frequency mixing unit is used for mixing a test output signal of the polar coordinate transmitter with a frequency-down signal to generate a mixed signal. The signal processing unit is coupled to the frequency mixing unit and used for performing signal processing on the frequency-mixed signal to generate a processed signal. The estimation unit is coupled to the signal processing unit and used for performing distortion estimation according to the processed signal to generate a distortion estimation result. The compensation unit is coupled to the estimation unit and the input end of the polar transmitter, and is used for performing predistortion compensation on the input signal of the polar transmitter according to the estimation result.
An embodiment of the present invention provides a method for distortion estimation and compensation for a polar transmitter. The method comprises the following steps: mixing a test output signal of the polar transmitter with a down-converted signal to generate a mixed signal; processing the mixed signal to generate a processed signal; performing distortion estimation according to the processed signal to generate a distortion estimation result; and performing predistortion compensation on the input signal of the polar transmitter according to the distortion estimation result.
Drawings
Fig. 1 shows the non-linear distortion of a polar transmitter.
FIG. 2 is a diagram illustrating the structure and application of a distortion estimation and compensation apparatus according to an embodiment of the present invention.
FIG. 3 is a flowchart illustrating a distortion estimation and compensation method according to an embodiment of the present invention.
Detailed Description
In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the invention to the reader. However, those skilled in the art will understand how to implement the invention without one or more of the specific details, or with other methods or components or materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.
Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics described above may be combined in any suitable manner in one or more embodiments.
Please refer to fig. 2, which is a diagram illustrating a structure and an application of a distortion estimation and compensation apparatus according to an embodiment of the present invention. As shown, the distortion estimation and compensation apparatus 100 of the present invention is used for estimating and compensating the nonlinear distortion characteristic of the polar transmitter 200. The polar transmitter 200 includes a Coordinate Rotation Digital Computer (Cordic) processor 205, an amplitude modulation path 210, a phase modulation path 220, and a power amplifier 260. The polar transmitter 200 is configured to perform polar modulation and transmission according to a set of input in-phase (I)/quadrature (Q) signals. It should be noted that there may be other components or devices for performing polar modulation on the amplitude modulation path 210 and the phase modulation path 220 of the polar transmitter 200, but they are omitted here for simplicity and brevity of description. The cordic 205 is used to convert a set of I/Q signals to obtain corresponding polar coordinate signals a/P, which are respectively transmitted to the amplitude modulation path 210 and the phase modulation path 220, processed by the amplitude modulation path 210 and the phase modulation path 220, and finally transmitted to the power amplifier 260. The power amplifier 260 integrates the signals on the amplitude modulation path 210 and the phase modulation path 220 to output the result of polar modulation.
The distortion estimation and compensation apparatus 100 of the present invention includes (but is not limited to): coupler 105, test input unit 110, mixing unit 120, signal processing unit 130, estimation unit 140, and compensation unit 150. The coupler 105 may be an attenuation capacitor with a variable capacitance value for moderately attenuating the signal output from the power amplifier 260 and coupling it to the distortion estimation and compensation apparatus 100. In some embodiments of the invention, coupler 105 may be omitted. The test input unit 110 is used for providing a test input signal to the polar transmitter 200, so that the polar transmitter 200 generates a test output signal TS _ OUT. The test input unit 110 provides a digital test input signal S _ IN1KTo the amplitude modulation path 210 of the polar transmitter 200, so that the amplitude modulation path 210 outputs an amplitude signal S _ AMP. Furthermore, the test input unit 110 provides a constant test input signal S _ IN2 to the phase modulation path 220 of the polar transmitter 200 for phase modulationThe signal generating device 224 on the path 220 (in one embodiment, the signal generating device 224 may be a phase locked loop) generates an oscillating signal S _ PHA with a frequency f1 accordingly. The signals S _ AMP and S _ PHA on the amplitude modulation path 210 and the phase modulation path 220 cause the power amplifier 260 to generate the test output signal TS _ OUTKWherein the test output signal TS _ OUTKCan be represented as AKcos(2πf1t+θK)。
The index K represents the sequence of performing the distortion estimation by inputting different test input signals S _ IN1KObserve the test output signal TS _ OUT produced by the power amplifier 260KThereby estimating the non-linear characteristic of the power amplifier 260. A. theKThe amplitude θ of the power amplifier 260 in response to the input signal S _ AMPK--The phases of the power amplifier 260 generated in response to the input signals S _ AMP and S _ PHA.
The mixing unit 120 is used for outputting the test output signal TS _ OUTKMixing with a DOWN-converted signal S _ DOWN to generate a MIXED signal S _ MIXED. The DOWN-converted signal S _ DOWN is generated by the signal generating device 125 (in an embodiment, the signal generating device 125 can be a phase-locked loop). The signal generating device 125 is controlled by the control signal S _ IN3 to generate a DOWN-converted signal S _ DOWN with a frequency substantially fixed at f2, wherein the DOWN-converted signal S _ DOWN can be represented as Bcos
In this way, the MIXED signal S _ MIXED generated after the mixing process includes a signal component with a frequency of (f1+ f2) and a signal component with a frequency of (f1-f 2). Furthermore, the signal processing unit 130 is configured to perform a series of signal processing on the MIXED signal S _ MIXED, and then generate a processed signal S _ PROC. The signal processing unit 130 includes (but is not limited to): a filter 132, an analog-to-digital converter 134, and a Fast Fourier Transform (Fast Fourier Transform) unit 136. The filter 132 is used for performing a filtering process on the MIXED signal S _ MIXED to generate a filtered signal S _ FIL. The filter 132 can be a low-pass filter, so that the MIXED signal S _ MIXED is betterHigh frequency signal components, such as high frequency signal components having a frequency of (f1+ f2), are filtered out by the filter 132 to retain low frequency signal components having a frequency of (f1-f 2). Therefore, the filtered signal S _ FIL can be expressed as:
the adc 134 performs an analog-to-digital conversion on the filtered signal S _ FIL to generate a converted signal S _ CONV. The fft processing unit 136 is configured to perform a fast fourier transform on the converted signal S _ CONV to generate a processed signal S _ PROC, wherein the fft processing unit 136 can extract an amplitude value M from the converted signal S _ CONVKAnd a phase value PKAnd outputs these information to the estimating unit 140 via the processed signal S _ PROC. Wherein the amplitude value MKAmplitude BA corresponding to the filtered signal S _ FILKWhile phase value PK-Corresponds to the phase of the filtered signal S _ FIL
The estimation unit 140 is configured to perform distortion estimation according to the processed signal S _ PROC provided by the fast fourier transform processing unit 136 to generate a distortion estimation result DIS _ INFO. Wherein, the evaluation unit 140 records each set of test input signals S _ IN1KThe amplitude value M obtained when the amplitude value is inputted to the polar transmitter 200KAnd a phase value PK. By way of further analysis, the estimation unit 140 may derive therefrom the amplitude a of the output signal generated by the power amplifier 260 at different input amplitudesKAnd phase thetaKThus, characteristics of the power amplifier 260 such as amplitude modulation to amplitude modulation (AM-AM) distortion and amplitude modulation to phase modulation (AM-PM) distortion can be estimated (as shown in fig. 1). After the analysis is completed, the distortion estimation result DIS _ INFO is sent to the compensation unit150, the compensation unit 150 performs a Pre-distortion (Pre-distortion) compensation (according to an inverse function relationship) on the input signals of the amplitude modulation path 210 and the phase modulation path 220 of the polar transmitter 200 respectively based on the distortion estimation result DIS _ INFO, so as to cancel the AM-AM distortion and the AM-PM distortion caused by the non-linear characteristic of the power amplifier 260.
FIG. 3 is a flowchart illustrating a distortion estimation method according to an embodiment of the present invention. First, in step 300, an index value K is set to an initial value. IN step 310, a test input is determined according to the current index value K, and a test input signal S _ IN1 is generatedKThe amplitude modulation path 210 is provided with the signal S _ AMP, and the phase modulation path 220 is provided with the test input signal S _ IN2, so that the signal generating device 224 on the phase modulation path 220 generates the signal S _ PHA with the frequency f1, and the power amplifier 260 generates the test output signal TS _ OUT. In step 320, the test output signal TS _ OUT and the DOWN-converted signal S _ DOWN are MIXED to obtain a MIXED signal S _ MIXED. In step 330, the MIXED signal S _ MIXED is signal processed to obtain a processed signal S _ PROC. In step 340, an amplitude value M corresponding to the current pointer value K is obtained according to the processed signal S _ PROCKAnd phase value PK. In step 350, it is determined whether the index value K is the maximum value; if not, go to step 355, increment the index value K, and go back to step 310; if yes, go to step 360 according to the amplitude value MKAnd phase value PKA distortion estimation result is generated and predistortion compensation is performed accordingly.
In summary, the distortion estimation and compensation apparatus and method of the present invention can effectively solve the problem of non-linear distortion of the power amplifier in the conventional polar transmitter. In the non-linear distortion estimation architecture provided by the invention, a frequency demultiplication technique is utilized, so that the output signal of the power amplifier is in a frequency band which is easier to observe. Then, through a series of signal processing techniques, the amplitude modulation distortion and the phase modulation distortion are estimated. Based on the distortion estimation result, the polar coordinate transmitter is effectively subjected to predistortion compensation, so that the nonlinear defect of the power amplifier is overcome.
Embodiments of the invention may be implemented using hardware, software, firmware, and combinations thereof. Embodiments of the invention may be implemented using software or firmware stored in a memory with an appropriate instruction execution system. In terms of hardware, this can be accomplished using any or a combination of the following techniques: an individual arithmetic logic device having logic gates for performing logic functions according to data signals, an Application Specific Integrated Circuit (ASIC) having suitable combinational logic gates, a Programmable Gate Array (PGA) or a Field Programmable Gate Array (FPGA), etc.
The flowcharts and blocks in the flowcharts within this specification illustrate the architecture, functionality, and operation of what may be implemented by systems, methods and computer software products according to various embodiments of the present invention. In this regard, each block in the flowchart or functional block diagrams may represent a module, segment, or portion of program code, which comprises one or more executable instructions for implementing the specified logical function(s). In addition, each block of the functional block diagrams and/or flowchart illustrations, and combinations of blocks, can be implemented by substantially special purpose hardware systems that perform the specified functions or acts, or combinations of special purpose hardware and computer program instructions. These computer program instructions may also be stored in a computer-readable medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium implement the function/act specified in the flowchart and/or block diagram block or blocks.
The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.
[ notation ] to show
100 distortion estimation and compensation device
110 test input unit
120 mixing unit
125. 224 signal generating device
130 signal processing unit
132 filter
134 analog-to-digital converter
136 fast fourier transform unit
140 estimation unit
150 compensation unit
200 polar coordinate transmitter
205 coordinate rotation digital computation processor
210 amplitude modulation path
220 phase modulation path
260 power amplifier
I. Q inphase/quadrature signal
A. P amplitude/phase signal
S _ AMP amplitude signal
S _ PHA oscillation signal
TS_OUTKTesting output signals
S _ MIXED MIXED signal
S _ DOWN frequency-reducing signal
S _ FIL filtered signal
S _ CONV converted signal
S _ PROC processed signal
DIS _ INFO distortion estimation result
S_IN1KS _ IN2 test input signal
S _ IN3 controls the signal.
Claims (10)
1. An apparatus for distortion estimation and compensation for a polar transmitter, comprising:
a frequency mixing unit for mixing a test output signal of the polar transmitter with a down-converted signal to generate a mixed signal;
a signal processing unit, coupled to the frequency mixing unit, for performing signal processing on the frequency-mixed signal to generate a processed signal;
an estimating unit, coupled to the signal processing unit, for performing distortion estimation according to the processed signal to generate a distortion estimation result; and
and a compensation unit, coupled to the estimation unit and the polar transmitter, for performing predistortion compensation on the input signal of the polar transmitter according to the distortion estimation result.
2. The apparatus of claim 1, wherein the signal processing unit comprises:
a filter for filtering the mixed signal to generate a filtered signal;
an analog-to-digital converter, coupled to the filter, for performing an analog-to-digital conversion on the filtered signal to generate a converted signal; and
a fast fourier transform processing unit, coupled to the analog-to-digital converter, for performing a fast fourier transform on the converted signal to generate the processed signal.
3. The apparatus of claim 1, further comprising:
a test input unit for providing a first test input signal and a second test input signal to the polar transmitter, wherein the first test input signal is provided to an amplitude modulation path of the polar transmitter, and the second test input signal is provided to a phase modulation path of the polar transmitter, so that a power amplifier in the polar transmitter outputs the test output signal.
4. The apparatus of claim 3, wherein the phase modulation path includes a first signal generating device, the first signal generating device generating an oscillating signal having a first frequency according to the second test input signal.
5. The apparatus of claim 4, further comprising:
the second signal generating device is coupled to the frequency mixing unit and used for generating the frequency-down signal with a second frequency, wherein the second frequency is different from the first frequency.
6. A method for distortion estimation and compensation for a polar transmitter, comprising:
mixing a test output signal of the polar transmitter with a down-converted signal to generate a mixed signal;
processing the mixed signal to generate a processed signal;
performing distortion estimation according to the processed signal to generate a distortion estimation result; and
and performing predistortion compensation on the input signal of the polar transmitter according to the distortion estimation result.
7. The method of claim 6, wherein the step of signal processing the mixed signal comprises:
performing a filtering process on the mixed signal to generate a filtered signal;
performing an analog-to-digital conversion on the filtered signal to generate a converted signal; and
a fast Fourier transform is performed on the transformed signal to generate the processed signal.
8. The method of claim 6, further comprising:
providing an amplitude modulation path for a first test input signal to the polar transmitter, and providing a phase modulation path for a second test input signal to the polar transmitter, such that a power amplifier in the polar transmitter outputs the test output signal.
9. The method of claim 8, wherein generating the test output signal comprises:
an oscillation signal having a first frequency is generated on the phase modulation path according to the second test input signal.
10. The method of claim 9, wherein mixing the test output signal with the down-converted signal comprises:
the down-converted signal is generated with a second frequency different from the first frequency.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010225181.3A CN113452634A (en) | 2020-03-26 | 2020-03-26 | Apparatus and method for non-linear distortion estimation and compensation in polar transmitter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010225181.3A CN113452634A (en) | 2020-03-26 | 2020-03-26 | Apparatus and method for non-linear distortion estimation and compensation in polar transmitter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113452634A true CN113452634A (en) | 2021-09-28 |
Family
ID=77807603
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010225181.3A Pending CN113452634A (en) | 2020-03-26 | 2020-03-26 | Apparatus and method for non-linear distortion estimation and compensation in polar transmitter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113452634A (en) |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20000031138A (en) * | 1998-11-03 | 2000-06-05 | 정선종 | Pre-compensator of transmission system including linear distortion and nonlinear distortion and method for estimating delay between transmission signal and feedback signal and phase difference therebetween |
| KR20010064260A (en) * | 1999-12-27 | 2001-07-09 | 오길록 | Adaptive pre-distortion system for nonlinear distortion compensation in IMT-2000 system |
| US20020085647A1 (en) * | 1999-07-28 | 2002-07-04 | Yasuyuki Oishi | Radio apparatus having distortion compensating function |
| JP2002359655A (en) * | 2001-05-31 | 2002-12-13 | Nec Corp | Circuit and method for compensating distortion |
| US20060178120A1 (en) * | 2005-02-10 | 2006-08-10 | Infineon Technologies Ag | Transmitting/receiving device having a polar modulator with variable predistortion |
| US7346122B1 (en) * | 2002-08-21 | 2008-03-18 | Weixun Cao | Direct modulation of a power amplifier with adaptive digital predistortion |
| CN101390285A (en) * | 2005-12-27 | 2009-03-18 | 松下电器产业株式会社 | Polar coordinate modulated transmission device, adaptive distortion compensation processing system, polar coordinate modulated transmission method, and adaptive distortion compensation processing meth |
| US20120039415A1 (en) * | 2010-08-13 | 2012-02-16 | Fujitsu Limited | Distortion compensation amplifier device and distortion compensation method |
| CN103166635A (en) * | 2011-12-15 | 2013-06-19 | 英特尔移动通信有限责任公司 | Method and faculty to measure and compensate dco frequency distortions using a dpll |
| US20160142230A1 (en) * | 2014-11-14 | 2016-05-19 | TallannQuest, Inc. | Power-efficient digital wireless transmitter and method of operation thereof |
| US20190036749A1 (en) * | 2017-07-28 | 2019-01-31 | Texas Instruments Incorporated | Transmitter time-domain estimation and compensation of iq imbalance |
-
2020
- 2020-03-26 CN CN202010225181.3A patent/CN113452634A/en active Pending
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20000031138A (en) * | 1998-11-03 | 2000-06-05 | 정선종 | Pre-compensator of transmission system including linear distortion and nonlinear distortion and method for estimating delay between transmission signal and feedback signal and phase difference therebetween |
| US20020085647A1 (en) * | 1999-07-28 | 2002-07-04 | Yasuyuki Oishi | Radio apparatus having distortion compensating function |
| KR20010064260A (en) * | 1999-12-27 | 2001-07-09 | 오길록 | Adaptive pre-distortion system for nonlinear distortion compensation in IMT-2000 system |
| JP2002359655A (en) * | 2001-05-31 | 2002-12-13 | Nec Corp | Circuit and method for compensating distortion |
| US7346122B1 (en) * | 2002-08-21 | 2008-03-18 | Weixun Cao | Direct modulation of a power amplifier with adaptive digital predistortion |
| US20060178120A1 (en) * | 2005-02-10 | 2006-08-10 | Infineon Technologies Ag | Transmitting/receiving device having a polar modulator with variable predistortion |
| CN101390285A (en) * | 2005-12-27 | 2009-03-18 | 松下电器产业株式会社 | Polar coordinate modulated transmission device, adaptive distortion compensation processing system, polar coordinate modulated transmission method, and adaptive distortion compensation processing meth |
| US20120039415A1 (en) * | 2010-08-13 | 2012-02-16 | Fujitsu Limited | Distortion compensation amplifier device and distortion compensation method |
| CN103166635A (en) * | 2011-12-15 | 2013-06-19 | 英特尔移动通信有限责任公司 | Method and faculty to measure and compensate dco frequency distortions using a dpll |
| US20160142230A1 (en) * | 2014-11-14 | 2016-05-19 | TallannQuest, Inc. | Power-efficient digital wireless transmitter and method of operation thereof |
| US20190036749A1 (en) * | 2017-07-28 | 2019-01-31 | Texas Instruments Incorporated | Transmitter time-domain estimation and compensation of iq imbalance |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101234963B1 (en) | I/q calibration of transmit and receive paths in ofdm fdd communication systems | |
| JP5512718B2 (en) | Fast in-phase quadrature unbalance calibration | |
| US10998926B2 (en) | Method for compensating gain flatness of transceiver | |
| US20190222264A1 (en) | Rf system using am with orthogonal offset | |
| CN102163956B (en) | Signal feedback loop and method for predistorter, power amplification equipment | |
| EP1916764B1 (en) | Method and apparatus for compensating for mismatch occurring in radio frequency quadrature transceiver | |
| CN103986484B (en) | Compensation method for unbalanced broadband intermediate frequency signal amplitudes | |
| CN104954294A (en) | Transmitter branch phase mismatch detection and correction system | |
| TWI760716B (en) | Method and apparatus for use in polar transmitter to perform nonlinearity distortion estimation and compensation | |
| US7411463B2 (en) | Method, system, apparatus, and program for measuring the damping factor of an Nth order phase locked loop (PLL) | |
| CN113452634A (en) | Apparatus and method for non-linear distortion estimation and compensation in polar transmitter | |
| US9973219B2 (en) | Predistortion system and method | |
| Creaney et al. | Designing efficient digital up and down converters for narrowband systems | |
| US8532590B2 (en) | Digital phase feedback for determining phase distortion | |
| JPH05110369A (en) | Phase shifter | |
| CN114337699B (en) | Self-adaptive carrier cancellation device and method for zero intermediate frequency transmitter | |
| KR101980862B1 (en) | Apparatus and methods for phase synchronization of local oscillators in a transceiver | |
| EP3151500B1 (en) | Frequency-selective quadrature baseband coupling cancellation | |
| CN108028671A (en) | Radio frequency system and method for polarity phase distortion calibration | |
| CN112653526A (en) | Device and method for testing nonlinear distortion of frequency hopping transmitter | |
| TW201735556A (en) | Apparatus and method for providing fast second order input intercept point calibration based on two tone testing | |
| CN104218959A (en) | Design method of analog-variable-frequency-free radio frequency digitizing transmitter and transmitter | |
| US8060045B2 (en) | Method for compensating the non-linear distortions of high-frequency signals and device for carrying out said method | |
| US8538349B2 (en) | Method and device for pre-distorting an exciter and predistortion exciter | |
| CN101694986A (en) | Vector modulation error compensation method based on analog base band correction |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |