JP2005341117A - Nonlinear distortion compensator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a storage area of a distortion compensation data holding unit for storing a distortion compensation data group in a transmitter of a wireless communication system adaptively performing digital predistortion.
The input power to the amplifying unit is changed stepwise to limit each power section, the range of the distortion compensation data group is divided accordingly, and a partial distortion compensation data group is selected. Further, by repeatedly adjusting the power section while selecting a partial distortion compensation data group, the distortion compensation data over the entire necessary power section is finally selected.
[Selection] Figure 1

Description

  The present invention relates to a nonlinear distortion compensation apparatus that compensates for nonlinear distortion of an amplifier used in a transmitter of a wireless communication system.

  In a transmitter of a wireless communication system, an amplifier is indispensable in order to transmit a radio wave from an antenna to the air after electrically amplifying a signal to be transmitted. In this type of amplifier, efficiency of power consumption is being promoted in order to save power. However, in general, a high-efficiency amplifier exhibits input / output characteristics including nonlinear components in its output (power and phase) when the input power becomes relatively high. This is usually called “non-linear distortion”. If the amount of nonlinear distortion increases, the quality of wireless communication deteriorates, and as a result, communication may not be possible. Here, the output power characteristic with respect to the input power of the amplifier is referred to as an AM-AM characteristic, and the output phase characteristic with respect to the input power is referred to as an AM-PM characteristic.

  As a method for compensating nonlinear distortion, a nonlinear distortion compensation method using a digital signal that can be realized relatively easily has been proposed. This method presupposes that the signal is distorted by the amplifier, and applies a nonlinear distortion having the inverse characteristic in advance by digital signal processing to cancel the nonlinear distortion due to the nonlinear input / output characteristic of the amplifier. This method is called “digital predistortion method”. Data for applying nonlinear distortion is called “distortion compensation data”.

  Incidentally, the input / output characteristics of an amplifier generally vary depending on environmental conditions such as temperature conditions and aging conditions, operating years, drive voltage levels, and the like. For this reason, if distortion compensation data used in digital predistortion is fixed, nonlinear distortion cannot be effectively compensated for a long period of time. The input / output characteristics (distortion characteristics) of the amplifier have individual differences even if the production lot is the same. For this reason, even when amplifiers having the same product model number are used, it is not effective to compensate for nonlinear distortion using the same distortion compensation data. On the other hand, since it is not efficient to measure the distortion characteristics of all amplifiers, the same distortion compensation data is often used in practice. Thus, when performing distortion compensation using distortion compensation data that does not match the actual distortion characteristics, digital predistortion may have an adverse effect. Therefore, it is necessary for the operation to sequentially update the distortion compensation data.

  In the digital predistortion, when the distortion compensation data cannot completely cancel the nonlinear distortion in the amplifier, the nonlinear distortion component remains in the amplified signal, and this distortion component appears on the spectrum as a component outside the effective band. Therefore, if the distortion component power is measured while changing the distortion compensation data, the distortion compensation data is manipulated so that it is reduced, and the distortion compensation data is updated so as to substantially cancel the nonlinear distortion of the amplifier. Data can be determined.

  In a transmitter of a conventional wireless communication system, nonlinear distortion of an amplifier is compensated by such digital predistortion, and distortion component power observed as an out-of-band component on the spectrum is detected and reduced. As a method for compensating for nonlinear distortion of an amplifier while updating distortion compensation data, the following has been proposed.

  FIG. 8 shows a configuration example of a conventional nonlinear distortion compensator (Non-Patent Document 1). In the figure, an orthogonal baseband signal 1 input as a transmission signal is input to a distortion compensator 11 and a power calculator 12. The power calculator 12 calculates the signal power of the orthogonal baseband signal 1 and outputs the value to the distortion compensation data unit 14. The distortion compensation data unit 14 stores a distortion compensation data group in which each signal power is associated with distortion compensation data for compensating for nonlinear distortion caused by nonlinear AM-AM characteristics and AM-PM characteristics of the amplification unit 16. The distortion compensation data 2 corresponding to the signal power input from the power calculator 12 is read and output to the distortion compensator 11. Here, the distortion compensation data is composed of amplitude compensation data and phase compensation data.

  The distortion compensator 11 calculates a complex product of the orthogonal baseband signal 1 and the distortion compensation data 2 corresponding to the signal power, and provides the orthogonal baseband to which the nonlinear distortion generated by the amplifier 16 and the nonlinear distortion having the opposite characteristic are given. The signal is output to the quadrature modulation unit 15. The orthogonal modulation unit 15 performs orthogonal modulation on the orthogonal baseband signal subjected to distortion compensation processing by the distortion compensation unit 11, and amplifies the modulation signal to a predetermined level by the amplification unit 16. The modulated signal 3 amplified and compensated for distortion by the amplifying unit 16 is transmitted as a radio signal, and a part thereof is distributed via the distributing unit 17 and input to the filter 21. The filter 21 separates out-of-effective-band components (distortion components) from the amplified modulated signal 3 and outputs the separated components to the power detection unit 22.

  The power detection unit 22 detects the distortion component power included in the modulation signal 3 and outputs it to the distortion compensation data control unit 23. The distortion compensation data control unit 23 updates the distortion compensation data group stored in the distortion compensation data unit 14 by perturbation or the like so as to reduce the detected distortion component power, and sets an optimal distortion compensation data group. Here, a plurality of distortion compensation data groups Gr1 to GrM having different characteristics are held in the distortion compensation data holding unit 13, and one distortion compensation data group Gri is selected by the distortion compensation data control unit 23 to be used as the distortion compensation data unit 14. The distortion compensation data corresponding to each signal power is updated.

  A control procedure of the distortion compensation data control unit 23 at this time will be described. First, predetermined distortion compensation data corresponding to the signal power of the orthogonal baseband signal 1 is selected from the distortion compensation data group initially set in the distortion compensation data section 14, and the distortion compensation section 11 to which the distortion compensation data is applied. Distortion compensation is performed, and distortion component power that is a component outside the effective band of the modulation signal 3 amplified by the amplification unit 16 is measured. The distortion component power measured first is stored in the distortion compensation data control unit 23 as it is. The distortion compensation data control unit 23 temporarily changes the distortion compensation data group of the distortion compensation data unit 14 using the data held by the distortion compensation data holding unit 13, and the distortion component power for the distortion compensation data and the previous distortion component. Compare with power and detect the increase or decrease.

  Here, when the distortion component power decreases with respect to the change of the distortion compensation data group of the distortion compensation data unit 14, the distortion compensation data group temporarily changed is determined and the distortion component power detected at that time is determined. Remember. Furthermore, a new distortion compensation data group in the same direction is set for the determined distortion compensation data group, and this procedure is repeated again. On the other hand, when the distortion component power increases, the temporarily changed distortion compensation data group is invalidated, and the distortion component power detected at that time is not stored. Further, a new distortion compensation data group in the reverse direction is set for the invalid distortion compensation data group, and this procedure is repeated again. The change direction of the distortion compensation data group corresponds to the change direction of the input / output characteristics (distortion characteristics) of the amplifying unit 16 assumed to change the distortion compensation data group.

  As described above, the distortion compensation data control unit 23 measures the distortion component power while changing the distortion compensation data group, and determines distortion compensation data that can minimize the nonlinear distortion from the state of change of the distortion component power. The optimum distortion compensation data group to be stored in the distortion compensation data unit 14 can be determined following the change in input / output characteristics of the amplification unit 16.

Normally, the change in the input / output characteristics of the amplifying unit 16 is gradual due to the above-described change over time. Therefore, the period for updating the distortion compensation data group for the distortion compensation data unit 14 may be long to some extent, and the period (comparison period) for monitoring the change in distortion component power with respect to the updating of the distortion compensation data group may be long to some extent. By increasing the comparison period of the distortion component power, the input orthogonal baseband signal 1 can be regarded as a random signal having a uniform distribution, and the signal power distribution generated over a long period of time is time-invariant (stationary system). Can be treated as Therefore, the power of the amplified out-of-band signal component (distortion component) is compared regardless of the signal pattern of the input orthogonal baseband signal 1, and even if the distortion compensation data group is updated based on the result, the wireless communication Quality does not deteriorate.
Proposal of perturbed baseband predistortion method, IEICE, Society Conference, B-5-205, Autumn 2003

  The conventional nonlinear distortion compensation apparatus assumes a distortion range of the amplifying unit 16 to some extent, has a distortion compensation data group that compensates for distortion occurring within the assumed range, and among these distortions, the distortion component power is small. A compensation data group is selected and rewritten.

  By the way, in order to increase the gain of the amplifying unit, there may be a method in which an amplifier having a small gain is internally connected in multiple stages. In this case, the gain of the amplifying unit is increased by the multi-stage connection, and the output is naturally increased. The output of the amplitude component is adjusted by the manufacturer, and is kept substantially linear in a region where the back-off is sufficiently taken.

  However, even a low gain amplifier has a phase change. The AM-PM characteristics when such amplifiers are connected in multiple stages often appear as if the characteristics of each amplifier are in multiple stages as shown in FIG. Not necessarily small. FIG. 10 shows the AM-PM characteristics actually measured. This is an example of characteristics when two low gain amplifiers are connected in series.

  The distortion compensation data holding unit 13 needs to hold a plurality of distortion compensation data groups for all generated signal powers in the amplification unit having such characteristics. Since this distortion compensation data pattern is due to individual differences of amplifiers with small gains connected in multiple stages, the greater the number of connection stages, the greater the number of combinations that express all characteristics, and the need for a large number of distortion compensation data patterns. Become. That is, the distortion compensation data holding unit 13 having a very large storage area is required.

  The present invention relates to a storage area of a distortion compensation data holding section for storing a distortion compensation data group when using an amplification section in which amplifiers with small gains are connected in multiple stages in a transmitter of a wireless communication system that adaptively performs digital predistortion. An object of the present invention is to provide a nonlinear distortion compensator that can reduce noise.

  The nonlinear distortion compensation apparatus of the present invention includes a level adjustment unit that adjusts the input power of the modulation signal input to the amplification unit stepwise from a low level to a high level, and is set by the level adjustment unit as a distortion compensation data holding unit. A first distortion compensation data holding unit that holds a plurality of distortion compensation data groups having different characteristics corresponding to a first power interval corresponding to a low level of input power, and high for the first power interval. A second distortion compensation data holding unit corresponding to the second power section of the level and having a plurality of distortion compensation data groups having different characteristics, and output from the first distortion compensation data holding unit The distortion compensation data group corresponding to the power section is set in the distortion compensation data section, and the second power output from the distortion compensation data group corresponding to the determined first power section and the second distortion compensation data holding section. Distortion compensation data group corresponding to the section A data combination unit configured to combine and set in the distortion compensation data unit, the distortion compensation data control unit sets the first power section in the level adjustment unit and corrects the input power calculated by the power calculation unit; Select the distortion compensation data group corresponding to the power interval of the first from the first distortion compensation data holding unit and perform the confirmation process, then set the second power interval in the level adjustment unit and correspond to the second power interval The distortion compensation data group to be selected is selected from the second distortion compensation data holding unit, and the determination process of the distortion compensation data group corresponding to the entire power section is performed.

  In the conventional nonlinear distortion compensator, in the process of selecting optimum distortion compensation data, the input power to the amplifier is constant, so the range of output power distribution is also constant, and the distortion compensation data group corresponding to the total power You will choose from

  On the other hand, in the nonlinear distortion compensator of the present invention, the input power to the amplifying unit is changed stepwise to limit each power section, and the range of the distortion compensation data group is divided accordingly, and the partial distortion is Select compensation data group. When the power interval input to the amplifier is known, only distortion compensation data corresponding to the power is used for distortion compensation, and distortion compensation data in other ranges is not involved in distortion compensation. Therefore, it is possible to adjust the power section and select a distortion compensation data group in a range corresponding to the power. Furthermore, by repeating the adjustment of the power section while selecting a partial distortion compensation data group, it is possible to select the distortion compensation data over the entire necessary power section.

  As a result, the distortion compensation data holding unit does not need to hold a plurality of patterns of distortion compensation data groups over the entire power section, and can hold a plurality of patterns of distortion compensation data groups in each power section and handle them in combination. Well, when the number of patterns in each section is plural (two or more), the storage area can be reduced.

(First embodiment)
FIG. 1 shows a first embodiment of the nonlinear distortion compensator of the present invention. The feature of this embodiment is that, in the conventional configuration shown in FIG. 8, a level adjustment unit 31 is arranged between the quadrature modulation unit 15 and the amplification unit 16 to adjust the power level of the modulation signal input to the amplification unit 16. A combination of distortion compensation data holding units 13A and 13B corresponding to the power generation range (here, section A and section B) and holding a plurality of specific different distortion compensation data groups, and each distortion compensation data group The unit 32 is provided. The distortion compensation data control unit 24 operates the level adjustment unit 31 based on the determined operating power level, and sets the distortion compensation data group corresponding to the power generation range (section A and section B) to the distortion compensation data holding section 13A. , 13B, and this is output to the data combination unit 32. The data combination unit 32 generates a distortion compensation data group corresponding to all input power levels by combining the distortion compensation data groups of the distortion compensation data holding units 13A and 13B and outputs the distortion compensation data group to the distortion compensation data unit 14. Further, the distortion compensation data control unit 24 notifies the determined operation power level to the power calculation unit 12, and the power calculation unit 12 corrects the calculated power value so that the notified operation power level is the average power. Other configurations are the same as the conventional configuration shown in FIG.

  The distribution unit 17 and the filter 21 are integrated, and the effective band component (signal component) and the out-of-effective band component (distortion component) are separated from the amplified and distortion-compensated modulation signal output from the amplification unit 16, and the effective band A configuration may be adopted in which an external component (distortion component) is sent to the power detection unit 22.

  Here, the relationship between the power generation range (section A and section B) of the input signal of the amplification unit 16 and the distortion compensation data group of the distortion compensation data holding units 13A and 13B will be described.

  FIG. 4 shows the relationship between the set value of average power and the power generation range of the input signal. When the average power A is set by the level adjusting unit 31, the power generation range is from the maximum power Amax to the minimum power Amin. When the average power B (> A) is set, the power generation range is from the maximum power Bmax to the minimum power Bmin, and the section B is from Amax to Bmax. When the signal transition on the complex plane passes near the origin, Amin and Bmin become values close to 0. That is, in the case of average power B, the power generation range is a combination of section A and section B, and the power generation range overlaps in the case of average power A and average power B.

  FIG. 5 shows a pattern example of the distortion compensation data group. The distortion compensation data holding unit 13A holds a plurality of distortion compensation data groups having different characteristics corresponding to the section A. The distortion compensation data holding unit 13B holds a plurality of distortion compensation data groups having different characteristics corresponding to the section B. Here, there are three types of distortion compensation data groups corresponding to section A, A1, A2, and A3, and three types of distortion compensation data groups corresponding to section B, B1, B2, and B3. Section A and section B are independent adjacent sections and do not overlap.

  Based on the above, the control procedure of the distortion compensation data control unit 24 in the present embodiment will be described. The distortion compensation data control unit 24 operates the level adjustment unit 31 so as to be in the power generation range of the section A, and sets the average power value at this time to A. As a result, the signal power input to the amplifying unit 16 is within the range of the section A. At the same time, the distortion compensation data holding unit 13A corresponding to the section A is controlled, a distortion compensation data group for compensating the distortion characteristics of the amplification unit 16 with respect to the power generation range of the section A is designated, and the data combination unit 32 outputs the data. . Further, the distortion compensation data control unit 24 notifies the set average power value A to the power calculation unit 12, and the power calculation unit 12 corrects the power calculation value based on the notified average power value A.

  In this state, distortion compensation is performed, and distortion component power that is a component outside the effective band of the modulation signal at that time is detected. Then, an optimal distortion compensation data group (A1, A2, A3) is selected from the distortion compensation data holding unit 13A so as to reduce this, and the data combination unit 32 and the distortion compensation data unit 14 select this as the distortion in the section A. Temporarily fixed as a compensation data group.

  Next, the distortion compensation data control unit 24 operates the level adjustment unit 31 so as to be in the power generation range of the section A + the section B, and sets the average power value at this time to B. As a result, the signal power input to the amplifying unit 16 is for all the sections including the section A and the section B. At the same time, the distortion compensation data holding unit 13B corresponding to the section B is controlled, a distortion compensation data group for compensating for the distortion characteristics of the amplification unit 16 with respect to the power generation range of the section B is designated, and the data combination unit 32 outputs the data. . The data combination unit 32 corrects the distortion compensation data group in the section A temporarily fixed previously and the transmitted distortion compensation data group so as to be a continuous distortion compensation data group, and sends the corrected data to the distortion compensation data unit 14. Furthermore, the distortion compensation data control unit 24 notifies the set average power value B to the power calculation unit 12, and the power calculation unit 12 corrects the power calculation value based on the notified average power value B.

  In this state, distortion compensation is performed, and distortion component power that is a component outside the effective band of the modulation signal at that time is detected. Then, an optimum distortion compensation data group (B1, B2, B3) is selected from the distortion compensation data holding unit 13B so as to reduce this. At this time, the distortion compensation data group in the section A is temporarily fixed and not changed. However, the data combination unit 32 combines the distortion compensation data groups so that the distortion compensation data groups in the sections A and B are continuous, and the distortion compensation data section 14 sets this as the distortion compensation data group in all sections.

  As a result, the optimization of the distortion compensation data group of all the sections combining the sections A and B is completed, and the distortion compensation using the optimal distortion compensation data group can be performed. FIG. 6 shows a combination pattern of the distortion compensation data group (A1, A2, A3) and the distortion compensation data group (B1, B2, B3) at this time. By combining the three distortion compensation data groups for section A and the three distortion compensation data groups for section B, it is possible to generate a total of nine patterns of distortion compensation data groups for all sections including section A and section B. Become. That is, nine distortion compensation data groups can cope with nine patterns of distortion compensation.

  On the other hand, in the case of the conventional method, it is necessary to prepare nine patterns of distortion compensation data groups as shown in FIG. 7 as distortion compensation data for all sections including the sections A and B from the beginning. That is, first, the distortion compensation data control unit 24 sets the average power B. As a result, the signal power input to the amplifying unit 16 is in a range in which the section A and the section B are combined. At the same time, the distortion compensation data group for section A and the distortion compensation data group for section B are combined and sent to the distortion compensation data section 14, and distortion component power is detected using nine patterns of distortion compensation data groups based on the respective combinations. It is necessary to perform distortion compensation.

In general, if the number of distortion compensation data group patterns in section A is a (≧ 2) and the number of distortion compensation data group patterns in section B is b (≧ 2), the combination of distortion compensation data groups in all sections The number is a × b. In the case of the conventional method, it is necessary to hold (a × b) distortion compensation data groups in advance, but in the present invention, this is supported by a combination of the distortion compensation data group in section A and the distortion compensation data group in section B. Therefore, it is sufficient to hold (a + b) distortion compensation data groups. Under the conditions of a ≧ 2 and b ≧ 2,
(A × b) ≧ (a + b)
Thus, it can be seen that as the number of patterns of the distortion compensation data group in each section increases, the number of distortion compensation data groups held can be reduced by the present invention, and the storage area of the distortion compensation data holding units 13A and 13B can be reduced. The same applies when the number of sections is three or more.

(Second Embodiment)
FIG. 2 shows a second embodiment of the nonlinear distortion compensator of the present invention. In the present embodiment, in the configuration of the first embodiment shown in FIG. 1, a frequency conversion unit 33 that converts a modulation signal into a predetermined frequency band is arranged before the level adjustment unit 31, and distributed by the distribution unit 17. A frequency reverse conversion unit 34 that reversely converts the modulated signal 3 into a predetermined frequency band and inputs the signal to the filter 21 is disposed, and the other configurations are the same.

  In a normal radio transmitter, the final stage amplification unit 16 is a radio frequency band amplifier that radiates into the air as it is, and has a configuration in which the frequency conversion unit 33 converts it to a relatively high radio frequency band. The modulation signal 3 in the relatively high radio frequency band may be directly input to the filter 21 and the component outside the effective band (distortion component) may be input to the power detection unit 23. By converting to a low frequency band, extracting an out-of-effective-band component (distortion component) with the filter 21 and inputting it to the power detection unit 22, the device cost including the filter 21 can be reduced.

  Further, the distribution unit 17 and the filter 21 are integrated to separate an effective band component (signal component) and an out-of-effective band component (distortion component) from the amplified and distortion-compensated modulated signal output from the amplifier 16 and out of the effective band. The component (distortion component) may be sent to the power detection unit 22 via the frequency inverse conversion unit 34.

(Third embodiment)
FIG. 3 shows a third embodiment of the nonlinear distortion compensator of the present invention. In the present embodiment, in the configuration of the first embodiment shown in FIG. 1 (the same applies to the configuration of the second embodiment shown in FIG. 2), instead of the distortion compensation data holding units 13A and 13B, a distortion compensation data creation unit 18A. , 18B. The distortion compensation data control unit 25 outputs information corresponding to the power difference between the distortion component powers to the distortion compensation data creation units 18A and 18B. Other configurations are the same.

  Based on instructions from the distortion compensation data control unit 25, the distortion compensation data creation units 18A and 18B create a plurality of patterns of distortion compensation data groups respectively corresponding to the sections A and B, and send them to the data combination unit 32. When it is easy to create distortion compensation data, or when it is difficult to hold a plurality of patterns of distortion compensation data in advance, distortion compensation data creation is performed instead of the distortion compensation data holding units 13A and 13B of the first embodiment. The use of the portions 18A and 18B can reduce the apparatus cost.

The figure which shows 1st Embodiment of the nonlinear distortion compensation apparatus of this invention. The figure which shows 2nd Embodiment of the nonlinear distortion compensation apparatus of this invention. The figure which shows 3rd Embodiment of the nonlinear distortion compensation apparatus of this invention. The figure which shows the relationship between average electric power and electric power generation | occurrence | production range. The figure which shows the example of a pattern of the distortion compensation data group of the area A and B. FIG. The figure which shows the combination pattern of the distortion compensation data group by this invention. The figure which shows the combination pattern of the conventional distortion compensation data group. The figure which shows the structural example of the conventional nonlinear distortion compensation apparatus. The figure which shows the structure of the amplifier 16. The figure which shows the characteristic of the amplifier 16.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Orthogonal baseband signal 2 Distortion compensation data 3 Modulation signal 11 Distortion compensation part 12 Power calculation part 13, 13A, 13B Distortion compensation data holding part 14 Distortion compensation data part 15 Orthogonal modulation part 16 Amplifier 17 Distribution part 18 Distortion compensation data preparation part DESCRIPTION OF SYMBOLS 21 Filter 22 Power detection part 23,24,25 Distortion compensation data control part 31 Level adjustment part 32 Data combination part 33 Frequency conversion part 34 Frequency reverse conversion part

Claims (4)

A power calculator for calculating the signal power of the input orthogonal baseband signal;
One distortion compensation data group composed of a plurality of distortion compensation data corresponding to the plurality of signal powers is stored, and distortion compensation data corresponding to the signal power is selected from the stored distortion compensation data groups. An output distortion compensation data part;
A distortion compensation data holding unit for storing a plurality of distortion compensation data groups having different characteristics each composed of a plurality of distortion compensation data;
A distortion compensation unit that performs signal processing on the orthogonal baseband signal using distortion compensation data output from the distortion compensation data unit, and generates an orthogonal baseband signal to which nonlinear distortion corresponding to the distortion compensation data is added; and
A quadrature modulation unit that quadrature modulates a quadrature baseband signal to which nonlinear distortion has been applied and outputs a modulation signal;
An amplifying unit having nonlinear input / output characteristics and amplifying and outputting the modulated signal;
A distribution unit that distributes a part of the modulation signal output from the amplification unit;
A filter that inputs the modulation signal distributed by the distribution unit and extracts an out-of-band effective component (distortion component);
A power detector for detecting distortion component power corresponding to an out-of-band component of the modulation signal extracted by the filter;
While temporarily changing the distortion compensation data group output from the distortion compensation data holding unit to the distortion compensation data unit, the change of the distortion component power is monitored, and the distortion compensation data group having the smallest distortion component power is obtained. A non-linear distortion compensation apparatus comprising: a distortion compensation data control unit that sets the distortion compensation data unit;
A level adjustment unit that adjusts the input power of the modulation signal input to the amplification unit stepwise from a low level to a high level;
As the distortion compensation data holding unit, a first distortion corresponding to a first power section corresponding to a low level input power set by the level adjustment unit and having a plurality of distortion compensation data groups having different characteristics A compensation data holding unit, and a second distortion compensation data holding unit corresponding to a second power section having a higher level than the first power section and holding a plurality of distortion compensation data groups having different characteristics. ,
A distortion compensation data group corresponding to the first power section output from the first distortion compensation data holding section is set in the distortion compensation data section and further defined as the distortion compensation data group corresponding to the first power section. And a data combination unit for combining the distortion compensation data group corresponding to the second power section output from the second distortion compensation data holding unit and setting the distortion compensation data unit,
The distortion compensation data control unit sets a first power section in the level adjustment unit and corrects input power calculated by the power calculation unit, and sets a distortion compensation data group corresponding to the first power section as the first power section. A selection is made from the first distortion compensation data holding unit and a confirmation process is performed. Subsequently, a second power interval is set in the level adjustment unit, and a distortion compensation data group corresponding to the second power interval is set as a second distortion. A nonlinear distortion compensator characterized by being configured to perform processing for determining a distortion compensation data group corresponding to the entire power section, selected from a compensation data holding unit. The nonlinear distortion compensator according to claim 1,
The level adjustment unit is configured to set three or more power intervals for the input power of the amplification unit,
The distortion compensation data holding unit includes three or more distortion compensation data holding units corresponding to three or more power sections,
The non-linear distortion compensation device, wherein the distortion compensation data control unit is configured to sequentially combine and determine a distortion compensation data group corresponding to each power section. The nonlinear distortion compensator according to claim 1,
A frequency converter that converts the modulation signal input to the amplifier into a predetermined frequency band;
A non-linear distortion compensation apparatus comprising: a frequency inverse transform unit that inversely transforms the modulation signal distributed by the distribution unit into a predetermined frequency band and inputs the signal to the filter. The nonlinear distortion compensator according to claim 1 or 2,
In place of the plurality of distortion compensation data holding units, the distortion compensation data control unit creates one of a plurality of distortion compensation data groups each having a different characteristic each configured by a plurality of distortion compensation data. A nonlinear distortion compensation apparatus, comprising: a plurality of distortion compensation data creating sections that output a compensation data group to the distortion compensation data section.

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