WO2005027340A1

WO2005027340A1 - Distortion compensating amplifier apparatus

Info

Publication number: WO2005027340A1
Application number: PCT/JP2004/013032
Authority: WO
Inventors: Ryoki Haramoto
Original assignee: Hitachi Kokusai Electric Inc.
Priority date: 2003-09-10
Filing date: 2004-09-08
Publication date: 2005-03-24
Also published as: JPWO2005027340A1

Abstract

[PROBLEMS TO BE SOLVED] A distortion compensating amplifier apparatus capable of performing a stable amplification without any distortion even a case of a region where an output level is linear for an input level. [MEANS FOR SOLVING PROBLEMS] A distortion compensating amplifier apparatus for compensating for distortion occurring during amplification, comprising an input level determining part (8) for determining the input level from an input signal; a distortion cancel signal combining part for generating a distortion cancel signal from the input signal and combining the distortion cancel signal with the input signal; an amplification part (6) for amplifying an output from the distortion cancel signal combining part; an output level determining part (9) for determining the output level from an output of the amplification part (6); and a control part (20) for controlling the distortion cancel signal combining part such that the distortion in the output of the amplification part (6) is reduced and such that in a case of a region where the output level of the amplification part (6) is linear for the input level, no distortion cancel signal is generated.

Description

Specification

Distortion compensation amplifier

Technical field

The present invention relates to a distortion compensation amplifier that compensates for distortion generated during amplification by a predistortion (PD) method. Further, the amplifying device according to the present invention can be applied to, for example, a base station device and a relay amplifying device provided in a wireless communication system such as a mobile communication system.

[0002] Here, as the wireless communication system, for example, various systems such as a mobile phone system and a simple mobile phone system (PHS: Personal Handy Phone System) may be used.

[0003] Examples of the communication system include, for example, a CDMA (Code Division Multiple Access) system, a W (Wide band) -CDMA system, a TDMA (Time Division Multiple Access) system, and an FDMA (Frequency Division Multiple Access) system. Various schemes may be used.

[0004] Here, the configuration of the amplifying device and the like according to the present invention is not necessarily limited to the configuration described above, and various configurations may be used. The present invention can be provided, for example, as a method or a method for executing the processing according to the present invention, or a program for realizing such a method or method.

[0005] The field of application of the present invention is not necessarily limited to the fields described above, and the present invention can be applied to various fields.

Background art

[0006] As a conventional distortion compensation amplification device, a distortion compensation amplification device based on the PD method has been proposed (for example, see Patent Document 1).

Patent Document 1: JP-A-2000-261252 (Pages 3-4, Fig. 1)

[0007] Here, a conventional distortion-compensating amplifier using the PD method will be described. FIG. 4 is a block diagram showing an example of a configuration of a conventional distortion compensation amplification device. As shown in FIG. 4, the conventional distortion compensating amplifier includes directional couplers 1, 7, a power distribution unit 2, a delay unit 3, a power combining unit 4, a PD unit 5, an amplifier 6, an input level detecting unit 8, It consists of an output level detector 9 and a controller 10. The

[0008] Next, the operation of the conventional distortion compensation amplification device will be described. First, an input signal is output to the power distribution unit 2 via the directional coupler 1. Further, a part of the input signal is extracted by the directional coupler 1 and output to the input level detector 8.

[0009] The input signal is distributed by power distribution section 2 to delay section 3 and PD section 5. The delay unit 3 delays one output of the power distribution unit 2 and outputs it to the power combining unit 4. Further, the PD unit 5 generates a distortion canceling signal, which is a signal for canceling distortion generated at the time of amplification by the amplifier 6, according to the control from the control unit 10, and outputs the other output power of the power distribution unit 2 to the power combining unit 4. Output.

[0010] Power combining section 4 combines the output of delay section 3 and the distortion canceling signal, and outputs the combined signal to amplifier 6. The amplifier 6 amplifies the combined signal and outputs the amplified signal to the directional coupler 7 as an amplified signal. Here, the distortion generated during amplification and the distortion canceling signal are canceled. The amplified signal is output to the outside via the directional coupler 7. Also, a part of the amplified signal is extracted by the directional coupler 7 and output to the output level detection unit 9. Note that an isolator (ISO) is provided on the output side of the directional coupler 7 to prevent the reflected wave from returning to the amplifier.

[0011] The input level detection unit 8 detects the power level of the input signal and outputs the detected power level to the control unit 10 as the input level. The output level detector 9 detects the power level of the amplified signal and outputs the detected power level to the controller 10 as an output level. The control unit 10 extracts a distortion level by comparing the input level and the output level, and controls the PD unit 5 so that the distortion level is reduced. Here, the output level detection unit may detect distortion itself which is not an output signal. When the distortion itself is detected, the PD section is controlled so that the distortion level is reduced according to the distortion level.

As described above, the distortion generated during amplification is compensated for by the distortion canceling signal generated by the PD unit 5.

Disclosure of the invention

Problems to be solved by the invention

[0013] However, in the above-described conventional distortion compensating amplifying device, the PD unit always operates and outputs a distortion canceling signal. Therefore, when the output level is linear with respect to the input level, In other words, a distortion canceling signal is output even if the amplified signal is at an input level without distortion. Therefore, there is a problem that the distortion canceling signal generated by the PD unit is output as distortion as it is.

The present invention has been made to solve the above-described problem, and can perform stable amplification without distortion even in a region where the output level is linear with respect to the input level. It is an object to provide a distortion compensation amplification device.

Means for solving the problem

[0015] In order to solve the above-described problem, a distortion compensation amplification device according to the present invention is a distortion compensation amplification device that compensates for distortion generated during amplification, and is an input level detection unit that detects an input signal power input level. And a distortion canceling signal that cancels distortion generated during amplification from the input signal, and amplifies an output of the distortion canceling signal combining unit that combines the input signal and the distortion canceling signal. An amplification unit, an output level detection unit that detects an output level from an output of the amplification unit, and a distortion cancellation signal synthesis unit that controls a distortion in the output of the amplification unit to reduce distortion. A control unit for controlling the distortion canceling signal synthesizing unit so as not to generate the distortion canceling signal in a region where the output level of the amplifying unit is linear. It is.

[0016] In the above-described distortion compensation amplification device, the distortion canceling signal synthesizing unit includes a power distribution unit that distributes the input signal, and a delay unit that delays one output of the power distribution unit. A preamplifier that amplifies the other output of the power distribution unit; a distortion cancellation signal generation unit that generates the distortion cancellation signal using an output of the preamplifier; an output of the delay unit and the distortion cancellation signal generation unit A power combining unit that combines the outputs of the amplifiers, wherein the control unit does not operate the preamplifier if the output level of the amplifying unit is linear with respect to the input level. It is.

In the above-described distortion compensation amplification device, the distortion canceling signal synthesizing unit includes a power distribution unit that distributes the input signal, and a delay unit that delays one output of the power distribution unit. A switch for inputting the other output of the power distribution unit, a distortion canceling signal generating unit for generating the distortion canceling signal using an output of the switch unit, an output of the delay unit and the distortion canceling signal. A power combining unit for combining the output of the generating unit, wherein the control unit If the output level of the amplifying unit is linear with respect to the power level, the switch unit is connected to a terminator.

In the above-described distortion compensation amplification device, the distortion canceling signal synthesizing unit includes a power distribution unit that distributes the input signal, and a delay unit that delays one output of the power distribution unit. A variable attenuator that receives the other output of the power distribution unit; a distortion cancellation signal generation unit that generates the distortion cancellation signal using an output from the variable attenuator; an output of the delay unit; A power combining unit that combines the output of the distortion canceling signal generation unit, wherein the control unit is configured such that, if the output level of the amplifying unit is linear with respect to the input level, the variable attenuator receives an input. It is characterized by attenuating a signal.

The invention's effect

According to the present invention, the distortion canceling signal is not generated when the input level does not cause distortion in the amplified signal, and the distortion canceling signal is generated when the input level causes distortion in the amplified signal. , Stable amplification with a wide range of input levels can be performed. BEST MODE FOR CARRYING OUT THE INVENTION

[0020] The distortion-compensating amplifier of the present invention prevents the PD section power from outputting a distortion canceling signal when the input level does not cause distortion in the amplified signal. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Example 1

FIG. 1 is a block diagram illustrating an example of a configuration of the distortion compensation amplification device according to the first embodiment.

In FIG. 1, the same reference numerals as those in FIG. 4 indicate the same or corresponding objects as those shown in FIG. 4, and the description thereof will be omitted. In the present embodiment, a control unit 20 is provided instead of the control unit 10, and a preamplifier 21 is provided between the power distribution unit 2 and the PD unit 5. Note that the distortion canceling signal combining unit in the present embodiment is the power distribution unit 2, the delay unit 3, the power combining unit 4, the PD unit 5, and the preamplifier 21.

The preamplifier 21 adjusts the level of each signal distributed to the delay unit 3 and the preamplifier 21 by the power distribution unit 2. For example, a signal input to the preamplifier side is amplified to the same level as a signal input to the delay line side.

Hereinafter, the operation of the distortion compensation amplification device according to the present embodiment will be described. When an input signal is input, the input level detection section 8 detects the input level, and the prosperity section 20 reads the detected input level. When the input signal is amplified by the amplifier 6, the control unit determines whether the input signal is amplified at a linear level or a non-linear level. For this determination, the amplification characteristic of the amplifier 6 may be grasped in advance, and this may be stored in a memory table or the like to determine whether the level is a linear level or a non-linear level. Further, a threshold value at which the level changes from the linear level to the non-linear level may be grasped in advance, and the determination may be made according to the threshold. Here, the threshold value and the table are not limited to one operation of the amplifier, for example, control a bias, and can cope with a case where an operation class or the like is changed.

After determining the input signal level, the control unit 20 controls the preamplifier 21. Specifically, when the input level detected by the input level detection unit 8 is at a level that does not cause distortion in the amplified signal, that is, when the signal has a linear level, the control unit 20 turns off the power of the preamplifier 21. As a result, no signal is input to the PD unit 5, and the distortion canceling signal is not output from the PD unit 5. On the other hand, if the input level detected by the input level detection unit 8 is a level that causes distortion in the amplified signal, that is, a non-linear level, the control unit 20 turns on the power supply of the preamplifier 21 so that the PD unit The signal is input to 5, and the distortion canceling signal is output from PD unit 5.

As described above, the control unit 20 controls the power supply of the preamplifier 21 according to the input level, so that when the input signal does not cause distortion in the amplified signal, only the linearly amplified signal is subjected to distortion compensation amplification. If the input level is output from the device and causes distortion in the amplified signal, a signal in which distortion during amplification has been compensated is output from the distortion compensation amplifier device.

Example 2

FIG. 2 is a block diagram illustrating an example of a configuration of the distortion compensation amplification device according to the second embodiment.

2, the same reference numerals as those in FIG. 4 denote the same or corresponding components as those shown in FIG. 4, and a description thereof will be omitted. In the present embodiment, a control unit 30 is provided instead of the control unit 10, and a switch 31 and a terminator 32 are provided between the power distribution unit 2 and the PD unit 5. Note that the distortion canceling signal combining unit in the present embodiment is the power distribution unit 2, the delay unit 3, the power combining unit 4, the PD unit 5, the switch 31, and the terminator 32.

Hereinafter, the operation of the distortion compensation amplification device according to the present embodiment will be described. When an input signal is input, the input level detector 8 detects the input level, and the controller 20 reads the detected input level. When the input signal is amplified by the amplifier 6, the control unit determines whether the input signal is amplified at a linear level or a non-linear level. For this determination, the amplification characteristic of the amplifier 6 may be grasped in advance, and the result may be stored in a memory table or the like to determine whether the level is a linear level or a non-linear level. Alternatively, a threshold value at which the level changes from the linear level to the non-linear level may be grasped in advance, and the determination may be made according to the threshold. Here, the threshold value and the table are not limited to one operation of the amplifier, but can control a bias, for example, and can cope with a case where an operation class or the like is changed.

After determining the input signal level, the control unit 30 controls the switch 31 in addition to the control of the PD unit 5. Specifically, when the input level detected by the input level detection unit 8 is a level that does not cause distortion in the amplified signal, the control unit 30 connects the switch 31 to the terminator 32 side. As a result, no signal is input to the PD unit 5, and no distortion cancellation signal is output from the PD unit 5. On the other hand, if the input level detected by the input level detection unit 8 is at a level that causes distortion in the amplified signal, the control unit 30 connects the switch 31 to the PD unit 5 side. As a result, a signal is input to the PD unit 5, and a distortion canceling signal is output from the PD unit 5.

[0028] As described above, the control unit 30 controls the switch 31 according to the input level, so that no distortion occurs in the amplified signal. If the input level is such that distortion occurs in the amplified signal, a signal in which the distortion during amplification is compensated is output from the distortion compensation amplifier.

Example 3

FIG. 3 is a block diagram illustrating an example of a configuration of the distortion compensation amplification device according to the third embodiment.

3, the same reference numerals as those in FIG. 4 denote the same or corresponding components as those shown in FIG. 4, and a description thereof will be omitted. In the present embodiment, a control unit 40 is provided instead of the control unit 10, and a variable attenuator 41 is provided between the power distribution unit 2 and the PD unit 5. Note that the distortion canceling signal combining unit in the present embodiment refers to the power distribution unit 2, the delay unit 3, the power combining unit 4, the PD unit 5, and the variable attenuator 41.

Hereinafter, the operation of the distortion compensation amplification device according to the present embodiment will be described.

When an input signal is input, the input level detection unit 8 detects the input level, and the control unit 20 Reads the detected input level. When the input signal is amplified by the amplifier 6, the control section determines whether the input signal is amplified at a linear level or a non-linear level. For this determination, the amplification characteristic of the amplifier 6 may be grasped in advance, and this may be stored in a memory table or the like to determine whether the level is a linear level or a non-linear level. Further, a threshold value at which the level changes from the linear level to the non-linear level may be grasped in advance, and the determination may be made according to the threshold. Here, the threshold value and the table are not limited to one operation of the amplifier, for example, control a bias, and can cope with a case where an operation class or the like is changed.

After determining the input signal level, the control unit 40 controls the variable attenuator 41 in addition to the control of the PD unit 5. Specifically, if the input level detected by the input level detector 8 is at a level that does not cause distortion in the amplified signal, the controller 40 controls the variable attenuator so that the input to the PD 5 is sufficiently attenuated. Control 41. As a result, no signal is input to the PD unit 5 and the distortion canceling signal of the PD unit 5 is not output. On the other hand, when the input level detected by the input level detection unit 8 is a level that causes distortion in the amplified signal, the control unit 40 controls the variable attenuator 41 so that the input to the PD unit 5 is not attenuated. . As a result, a signal is input to the PD unit 5, and a distortion canceling signal is output from the PD unit 5.

As described above, the control unit 40 controls the variable attenuator 41 in accordance with the input level, so that when the input signal does not cause distortion in the amplified signal, only the linearly amplified signal is distorted. If the output level is an input level that causes distortion in the amplified signal, the signal in which distortion during amplification is compensated is output from the distortion compensation amplifier. Here, the variable attenuator 42 includes a force variable attenuator configured to attenuate the input to the PD unit 5 at a stage prior to the PD unit 5 and a stage after the PD unit 5 to attenuate the output of the PD unit 5. Alternatively, the configuration may be such that the distortion canceling signal is suppressed to a level that does not cause distortion.

In the first to third embodiments, the example in which the input level detection unit 8 is provided has been described. However, a comparison unit is provided instead of the input level detection unit 8, and the comparison unit includes the preamplifier 21 or the preamplifier 21. May be configured to switch the switch 31 or the variable attenuator 41. In this case, the comparison unit compares the input level with a predetermined reference value, and switches the input so that the input to the PD unit 5 is provided if the input value is equal to or greater than the reference value, and the input is not provided to the PD unit 5 if the input value is equal to or less than the reference value. Do.

[0034] In the first to third embodiments, the input level detection unit 8 determines whether the analog input value is An analog comparator that compares the reference value may be used, or a digital comparator that includes an AZD converter and compares the digital input value and the reference value may be used.

[0035] Control of each component according to the input and output levels may be performed, for example, by incorporating control values of each component with respect to input / output values into a memory table and performing control based on the values in the memory table. .

In addition, as various processes performed by the amplifying device and the like according to the present invention, for example, a processor is stored in a ROM (Read Only Memory) in a hardware resource including a processor and a memory. A configuration controlled by executing a control program may be used. For example, each functional means for executing the process may be configured as an independent one-door circuit.

Further, the present invention can be understood as a computer-readable recording medium such as a floppy (registered trademark) disk or a CD (Compact Disk) -ROM storing the above-mentioned control program, or the program itself. It is possible to execute the processing according to the present invention by inputting the control program into the computer with the recording medium power and causing the processor to execute the control program.

As described in detail above, according to the present invention, when the input level is such that no distortion occurs in the amplified signal, control is performed so that the distortion canceling signal is not generated from the PD unit, and the distortion is generated in the amplified signal. If the input level occurs, the PD unit generates a distortion canceling signal and performs distortion compensation, so that even if the input level does not cause distortion in the amplified signal, the distortion canceling signal is output as distortion. Can be prevented.

Brief Description of Drawings

FIG. 1 is a block diagram illustrating an example of a configuration of a distortion compensation amplification device according to a first embodiment.

FIG. 2 is a block diagram illustrating an example of a configuration of a distortion compensation amplification device according to a second embodiment.

FIG. 3 is a block diagram illustrating an example of a configuration of a distortion compensation amplification device according to a third embodiment.

FIG. 4 is a block diagram showing an example of a configuration of a conventional distortion compensation amplification device.

Explanation of symbols

[0040] 1, 7 directional coupler, 2 power distribution section, 3 delay section, 4 power synthesis section, 5 PD section, 6 amplification section, 8 input level detection section, 9 output level detection section, 20, 30, 40 control, 21 Reamp, 31 switches, 32 terminators, 41 variable attenuators.

Claims

The scope of the claims

[1] A distortion compensation amplification device for compensating for distortion generated during amplification,

An input signal level; an input level detection unit for detecting an input level;

A distortion canceling signal synthesizing unit that generates, from the input signal, a distortion canceling signal for canceling distortion generated during amplification, and synthesizes the input signal and the distortion canceling signal;

An amplification unit that amplifies the output of the distortion cancellation signal synthesis unit,

An output level detection unit that detects an output level from an output of the amplification unit;

The distortion canceling signal synthesizing unit is controlled so that distortion in the output of the amplifying unit is reduced, and if the output level of the amplifying unit is linear with respect to the input level, the distortion canceling is performed. A control unit for controlling the distortion canceling signal synthesizing unit so as not to generate a signal;

A distortion compensation amplifying device comprising:

[2] The distortion compensation amplification device according to claim 1,

The distortion canceling signal synthesis unit includes:

A power distribution unit that distributes the input signal;

A delay unit that delays one output of the power distribution unit;

A preamplifier that amplifies the other output of the power distribution unit;

A distortion canceling signal generating unit that generates the distortion canceling signal using the output of the preamplifier, and a power combining unit that combines the output of the delay unit and the output of the distortion canceling signal generating unit,

Wherein the control unit does not operate the preamplifier in a region where the output level of the amplifying unit is linear with respect to the input level.

[3] The distortion-compensating amplifier according to claim 1,

The distortion canceling signal synthesis unit includes:

A power distribution unit that distributes the input signal;

A delay unit that delays one output of the power distribution unit;

A switch unit for inputting another output of the power distribution unit, A distortion cancellation signal generation unit that generates the distortion cancellation signal using an output of the switch unit; and a power synthesis unit that synthesizes an output of the delay unit and an output of the distortion cancellation signal generation unit.

The distortion compensating amplification device, wherein the control unit connects the switch unit to a terminator if the output level of the amplification unit is linear with respect to the input level.

In the distortion compensation amplification device according to claim 1,!

The distortion canceling signal synthesis unit includes:

A power distribution unit that distributes the input signal;

A delay unit that delays one output of the power distribution unit;

A variable attenuator that receives the other output of the power distribution unit;

A distortion cancellation signal generation unit that generates the distortion cancellation signal using an output from the variable attenuator;

A power combining unit that combines the output of the delay unit and the output of the distortion canceling signal generating unit,

The distortion amplifying device, wherein the control unit attenuates the input signal when the output level of the amplifying unit is linear with respect to the input level.