JP2003258563A - Distortion compensation amplifier adopting pre-distortion system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distortion compensation amplifier adopting the pre- distortion system for compensating distortion caused in an amplifier at a pre- stage of the amplifier when amplifying a signal of transmission object by the amplifier, where the power consumption is reduced. <P>SOLUTION: A signal level detection means 6 detects a level of a signal amplified by an amplifier 4 and amplifier bias control means 15, 16, 17 control a bias of the amplifier 4 so as to reduce the power consumed by the amplifier 4 by assuring that the level of distortion caused by the amplifier 4 is lower while satisfying a prescribed distortion level condition when a signal level detected by the signal level detection means 6 is low. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention
Signal generated by the amplifier when the signal is amplified by the amplifier
Pre-distortion method
Regarding distortion type distortion compensating amplification equipment, especially amplification
The present invention relates to a technique for reducing power consumption of a heater. In recent years, for example, CDMA (Code Division)
Mobile communication system that employs Multiple Access)
In the base station wireless amplifier installed in the system,
Power consumption, high efficiency and high linearity of wireless transmission circuit
Is required. Then, amplify the signal to be transmitted.
As a method of compensating for distortion generated in an amplifier, for example,
Adaptive predistortion by digital signal processing
Is used (hereinafter also referred to as APD method)
coming. The APD method includes a wireless signal input method and a base signal.
A baseband signal input method and the like have been studied. FIG. 7 shows an AP using a radio signal input method.
A typical configuration example of a D-system distortion compensating amplifier is shown.
You. It should be noted that the APD distortion compensation amplifier shown in FIG.
The configuration describes, for example, an embodiment according to the present invention described later.
APD type distortion compensation amplifier shown in FIG.
Is similar to a part of the configuration of FIG.
The same reference numerals N, 1 to 15, 21, and 22 are used for
And the detailed description is omitted here. FIG. 8 shows a case where a baseband signal input method is used.
A typical configuration example of the APD distortion compensation amplification device
I have. In the baseband signal input method, distortion compensation
The baseband signal is handled as an elephant signal. The same figure
The configuration of the APD type distortion compensation amplifier shown in FIG.
Drawings used to explain an embodiment according to the present invention to be described later.
6 and a part of the configuration of the APD distortion compensation amplification apparatus shown in FIG.
Because they are the same, similar components in both figures
The same symbols C1 to C4, 31 to 45, 51, 52 are assigned.
Therefore, detailed description is omitted here. [0005] However, the above described
In the distortion compensating amplification device as shown in the conventional example, for example,
The call load (traffic) on the station varies between daytime and nighttime
In contrast, the call load is generally smaller in the nighttime than in the daytime.
Radio frequency (RF: Radio Frequency) output power
Power amplifier operates despite lower power levels
More power at night with bias points than at night
Was fixed to a value suitable for daytime, which consumes
If the power amplifier wastes power,
There was such a problem. An example of the prior art will be introduced below.
These are different from the present invention to be described later in configuration and the like.
You. For example, as described in JP-A-7-326938.
"Amplifier bias control device" and Japanese Patent Application Laid-Open No. 11-289
No. 577, “Power control system of variable power amplifier”.
And its method "and JP-A-2000-315921.
In the “Negative feedback distortion compensation circuit” described in the official gazette,
The bias is controlled.
No. 8346, “Linearized power amplifier circuit”
Controlling the gain of the amplifier is performed. The present invention solves the above-mentioned conventional problems.
To amplify the signal to be transmitted.
The distortion generated by the amplifier when amplifying
When compensating by the distortion method,
Predistortion that can reduce power consumption
The purpose of the present invention is to provide an
You. [0008] To achieve the above object,
Therefore, the pre-distortion type distortion compensation according to the present invention is increased.
In a width device, the signal to be transmitted is amplified by an amplifier.
The distortion that occurs in the amplifier at the stage before the amplifier.
When compensating, set the amplifier bias as follows:
Control. That is, the signal level detecting means is controlled by the amplifier.
The level of the signal to be amplified is detected. And the amplifier bar
The bias control means is detected by the signal level detection means.
The level of distortion generated by the amplifier when the signal level is low.
That the bell falls below the specified distortion level
To reduce the power consumed by the amplifier.
Control the bias of the amplifier. Therefore, the level of the signal amplified by the amplifier is
The amplifier bias is controlled when the
Since the power consumed is reduced,
Low power consumption can be achieved. In addition, the amplifier
When controlling the noise, the level of distortion
Is low enough to meet predetermined distortion level requirements.
For example, distortion that occurs in an amplifier
Low power for the amplifier while keeping it small enough to not cause problems
Power consumption can be reduced. [0010] Specifically, for example,
A distortion type distortion compensation amplifier is used in a mobile communication system.
In the case where it is installed in the base station equipment of
During transmission, the level of the signal to be transmitted increases, while at night
Although the level of the signal to be transmitted will be lower,
Predistortion method distortion compensation for the situation
In the case of an amplifier, the specified distortion level condition is met at night.
While the power consumed by the amplifier is lower than during the day
In this way, the bias of the amplifier can be controlled. Here, the signal to be transmitted includes a seed
Various signals may be used, for example, depending on communication conditions.
A signal whose level changes in the same manner is used. Also,
Various amplifiers may be used as the amplifier.
For example, it is possible to amplify signals of multiple frequencies at once
A common amplifier is used. Also, as an amplifier,
For example, a single amplifier may be used, or
A combination of amplifiers may be used. Where multiple
If a combination of amplifiers is used,
The bias of some of the amplifiers may be controlled, or
The bias of the unit amplifier may be controlled. An amplifier generally amplifies a signal.
Causes distortion such as intermodulation distortion.
You. In the distortion compensation of the pre-distortion method,
For example, reduce distortion generated by the amplifier to zero or small
To generate distortion before the amplifier.
Thus, distortion generated in the amplifier is compensated. The amplifier
Is not necessarily the immediately preceding stage, the amplifier
This also includes a configuration in which another circuit exists between. In the signal level detecting means, for example,
The level of the signal before being amplified by the amplifier is detected,
For example, distortion compensation before amplification by an amplifier
The level of the signal before the
By detecting the level of the signal, such as after being amplified by
The amplifier bias is adjusted based on the detected signal level.
It is also possible to adopt a configuration for controlling. The signal level may be, for example, power
Level or amplitude level can be used. Ma
The amplifier bias is controlled by the amplifier bias control means.
As a mode of controlling, for example, the signal level and the amplifier
The method of controlling EAS is set in advance in association with
And control the bias of the amplifier according to the setting contents
Such an embodiment may be used or, for example, an amplifier
Amplifier vias based on the level of distortion caused by the
In such a case, a mode for controlling the power may be used. The signal level detected by the signal level detecting means is
Level of distortion generated by the amplifier when the signal level is low.
Level is lower than the specified distortion level condition.
To reduce the power consumed by the amplifier.
As a mode for controlling the bias of the amplifier, for example, a signal
According to the level detected by the level detector
Mode that continuously changes the bias of the amplifier
Or, for example, in the signal level detecting means.
One or more thresholds for the detected signal level
Amplify according to the magnitude relationship between the signal level and the threshold
Embodiments that change the bias of the vessel may be used.
No. Also, using such a threshold, for example, a plurality of signals
Level ranges are provided, and amplifiers are provided for each signal level range.
A mode in which the bias is changed may be used. Further, as the predetermined distortion level condition, for example,
For example, when transmitting signals to be transmitted wirelessly,
The distortion generated by the width gauge may affect other communication systems, etc.
Conditions that minimize the effect of interference
Is used as an example.
Conditions based on wireless standards for channel leakage power are used.
Specifically, the adjacent channel leakage power is set to a specified level.
Use conditions that keep the level below (or below)
You can. Generally, the power consumed by the amplifier is
By controlling the bias of the amplifier to lower it,
The linear characteristic of the amplifier deteriorates and occurs in the amplifier
For example, the level of distortion such as adjacent channel leakage power is high.
Become. For this reason, in the present invention, for example,
And the level of distortion generated by the amplifier.
Control the amplifier bias by weighing the
It is preferred to determine an aspect. Further, the bias of the plurality of amplifiers is controlled.
In the configuration, for example, two
Controlling the bias of the above amplifiers in the same way
Aspects may be used, or as many amplifiers as amplifiers
Separate bias for each amplifier
A mode of controlling in a manner may be used. Also,
For example, a small power amplifier, a medium power amplifier, and a large power amplifier
In configurations where a combination of
The power consumption of the power amplifier and the medium power amplifier is
It accounts for a large proportion of power consumption, so
Medium power control unit or high power control unit with fixed width bias
Efficient low power consumption by controlling the bias of
Can be achieved. Hereinafter, the predistortion according to the present invention will be described.
5 shows another example of the configuration of the distortion-type distortion compensation amplification device. In the present invention
In such a pre-distortion type distortion compensation amplification device,
As one configuration example, the amplifier bias control means includes a signal level controller.
Correspond to the control value for controlling the bias of the amplifier
It has a bias control value storage means for attaching and storing
Associated with the signal level detected by the bell detection means.
Using the control value stored in the bias control value storage means.
To control the amplifier bias. Here, as the bias control value storage means,
Is configured using, for example, a memory. Also, bias
As the signal level or control value stored in the control value storage means
Is, for example, a digital value. As an example, the signal
The control value is stored in the memory with the level as the address.
The signal level detected by the signal level detecting means.
Mode where control value is read from memory as address
Can be used. Further, the pre-distortion according to the present invention
In the system distortion compensation amplification device, as an example of the configuration, an amplifier is used.
A distortion level detecting means for detecting a level of the generated distortion.
Prepare. Then, the amplifier bias control means controls the distortion level.
Based on the distortion level detected by the
The level of the distortion generated by the width meter meets the specified distortion level condition.
Control the amplifier bias so that
You. Further, the pre-distortion according to the present invention
In the system distortion compensation amplifying device, as one configuration example,
When the bias control value storage means is used, the distortion level
Based on the distortion level detected by the
Bias control for updating the storage contents of the assurance control value storage means
A value storage content updating means is provided. Bias control value storage contents
The updating means is stored in, for example, the bias control value storing means.
Update the control value. Further, the above-described pre-division according to the present invention
The distortion type distortion compensating amplification device is, for example, a radio transmission
It is applied to devices and base station devices. Wireless transmission according to the present invention
In the transceiver, the signal to be transmitted is amplified and then
In the configuration for transmitting the data according to the present invention as described above,
Equipped with a redistribution distortion compensation amplification device,
Signal is increased by the predistortion method distortion compensation.
Amplify with a width device. In the base station apparatus according to the present invention,
In a configuration where signals are wirelessly communicated with the station equipment
The pre-distortion method according to the present invention as described above
A wireless transmitter having a distortion compensating amplifier is provided.
Wireless transmission of the sum of
You. In this case, for example, the sum of the signals to be transmitted is
Changes according to the communication situation. Specifically, for example, in the base station apparatus,
Sends the sum of signals to all mobile station devices
As the signal to be transmitted, the signal to be transmitted
Radio transmission by a line transmitter. In this case, for example,
The mobile station equipment whose signal level to be transmitted is
It changes according to the communication status such as the number of devices and the location. This
Here, as a wireless transmitter, a mobile station device, or a base station device
May have various configurations. As described above, the predistortion according to the present invention
Signal level detection in
Output of the amplifier according to the signal level detected by the output means.
Amplifier bias control means for controlling the bias is used.
You. Incidentally, the technology according to the present invention as described above, for example,
Limited to pre-distortion type distortion compensation amplifier
Generated by the amplifier when the signal is amplified by the amplifier
To various distortion compensating amplifiers that compensate for distortion
It is also possible to amplify the signal with an amplifier.
It is also possible to apply to a simple amplification device. Embodiments of the present invention will be described with reference to the drawings.
Will be explained. First, as a first embodiment according to the present invention,
Adaptive by radio signal input method to which the present invention is applied
Pre-distortion (APD) distortion compensation amplifier
An example will be described. FIG. 1 shows a wireless signal input system according to this embodiment.
A configuration example of an APD type distortion compensating amplifier according to the present invention is shown.
You. The input terminal of the APD distortion compensation amplifier of this example is
N, delay circuit 1, gain control circuit 2, phase control circuit
3, a power amplifier (Power AMP) 4, and directionality
Combiner 5, logarithmic amplifier (LOG AMP) 21 and A
/ D (Analog to Digital) converter 22
, A storage circuit 7, and a D / A (Digital to Analy
g) a converter 8, a storage circuit 9, a D / A converter 10,
Local signal generator 11, multiplication circuit 12, band-pass filter
Filter 13, A / D converter 14, data processing unit 15
, A storage circuit 16 and a D / A converter 17
I have. Here, the APD distortion compensation amplification device of this embodiment is used.
The configuration of the device is, for example, the APD system distortion compensation shown in FIG.
Components N, 1 to 15, 21, 22 similar to amplifying device
A storage circuit 1 for controlling the bias of the power amplifier 4
6 and a D / A converter 17
Thus, in this example, at low power levels,
Focusing on the large margin, the power amplifier 4 generates
Radio characteristics such as the level of distortion
Optimizing the bias control at the point where the bell occurs.
Here, as the wireless characteristics, for example, a CDMA signal is transmitted.
Channel leakage power (ACLR: Ad
jacent Channel Leakage power Ratio)
In this example, the ACLR is used. With the APD system distortion compensating and amplifying device of this embodiment,
An example of the operation to be performed will be described. APD system distortion compensation of this example
In the amplifier, a signal in the radio frequency band is input from the input terminal N.
Is forced. Then, the input signal is delayed by the delay circuit 1.
The level is controlled by the gain control circuit 2 to
After the phase is controlled by the phase control circuit 3, the power amplifier 4
Is amplified and output. Further, one of the signals input from the input terminal N
The unit is input to the power measuring device 6 via, for example, a directional coupler.
It is. The power measuring device 6 converts the input signal into a logarithmic amplifier.
21 and the amplification result is sent to the A / D converter 22.
Digital data obtained by A / D conversion (digital
Value) as the power value of the signal whose measured value has been measured.
Output to 5 The data processing unit 15 stores the digital data
Data. Then, under the control of the data processing unit 15,
The signal power value obtained by the power measuring device 6 is used as an address.
And the address stored in the gain control storage circuit 7.
The control value for gain control corresponding to
Is D / A converted by the D / A converter 8 and gain control circuit
2 to the control end. In the gain control circuit 2, the control terminal
Signal level using the gain corresponding to the control value input to
Control. For signal level control, amplify the signal
Or attenuate the signal level
A change is made. Similarly, under the control of the data processing unit 15,
The signal power value obtained by the power measuring device 6 is used as an address.
And the address stored in the phase control storage circuit 9.
The control value for phase control corresponding to
Is D / A converted by the D / A converter 10 and the phase control circuit
It is fed to the control end of the road 3. In the phase control circuit 3, the control
Signal using a phase change amount corresponding to the control value input to the
Signal phase control. The phase control of the signal
By increasing or decreasing the phase,
Changing the phase of the signal is performed. The amplified signal output from the power amplifier 4
Part of the signal is input to the multiplication circuit 12 via the directional coupler 5.
Is done. Local signal generator 11 receives data from data processing unit 15
Signal of a predetermined frequency (local frequency)
And outputs the signal to the multiplication circuit 12. Multiplication circuit 1
2, the signal input from the directional coupler 5 and the local signal
The signal input from the generator 11 is multiplied (mixed).
You. The multiplication result is band-controlled by the band-pass filter 13.
And the signal after the band limitation is processed by the A / D converter 14.
The data is then A / D converted and taken into the data processing unit 15. Here, as the band-pass filter 13,
Generated in the signal due to nonlinear distortion in the power amplifier 4
Fill with characteristics that allow out-of-band spectral components to pass
Is used. Also, the local signal generator 11
Out-of-band spectral components
Is controlled so as to generate signals of various frequencies. And
The data processing unit 15 enters through the band-pass filter 13.
The level of the signal applied, ie in the power amplifier 4
Out-of-band spectral components generated in the signal due to nonlinear distortion
Operate according to an algorithm that minimizes Ingredient
Specifically, the data processing unit 15 performs such a nonlinear distortion.
In order to minimize the effects of
Determine the storage contents (control values) of the roads 7 and 9 by trial and error
You. The storage circuit 16 is provided by the power measuring device 6.
The signal level detected by the
Controls the bias of the power amplifier 4 when a bell is detected
The control value used to perform the operation is stored. Here, the signal level
The bias control value corresponding to the
Radio characteristics such as the level of distortion generated in the amplifier 4 are AC
The power amplifier 4 falls within the range satisfying the LR standard and
Is set so that the power consumed by the
You. The data processing unit 15 controls the storage circuit 16
The signal level detected by the power measuring device 6
The control value corresponding to the address is stored in the storage circuit 16 as the
To the D / A converter 17. The control value is D
A / A converter 17 converts a digital value to an analog signal.
The signal is then input to the bias control terminal of the power amplifier 4.
The power amplifier 4 receives the analog signal input to the bias control terminal.
The bias is controlled by the log signal (the control value),
Perform width operation. Next, the APD type distortion compensating and amplifying apparatus of the present embodiment.
About the bias control of the power amplifier 4 performed by
This will be described in more detail. FIG. 2 shows the APD distortion of this example.
The bias of the power amplifier 4 is changed by the compensation amplifier.
An example of a processing procedure is shown. That is, the power meter
6, the input power value is measured (step S1),
When gain control or phase control is performed on the input power value,
Actually (step S2), the power is increased with respect to the input power value.
The bias of the width device 4 is controlled (step S3). FIG. 3 shows the power amplifier 4 according to the present embodiment.
When EAS control is performed (if the bias control is
Q) shows an example of the wireless characteristics in Q),
The bias control of the power amplifier 4 is not performed as in the conventional example.
(When the bias control is not performed)
An example of the characteristics is shown as Q3, and
An example of the wireless standard to be used is shown as Q1. here,
The horizontal axis of the graph indicates the output level of the power amplifier 4.
The vertical axis indicates wireless characteristics. Also, the horizontal axis of the graph
Shows the position of the maximum specified output. Note that the above
Thus, in this example, the ACLR is used as the wireless characteristic.
You. As shown in FIG.
When no control is performed (curve Q3), the output level is
The ACLR value increases as the standard output level approaches.
Therefore, the margin (interval) with respect to the wireless standard is reduced.
That is, the lower output level has more margin. Therefore, bias control is performed as in this embodiment.
In the case (curve Q2), the wireless characteristic Q2 matches the wireless standard Q1.
High power, especially at low power levels.
The bias control of the power amplifier 4 is performed. Where usually the power
The output level of the amplifier 4 is the input level of the power amplifier 4
In this example, the power meter
6 when monitoring the input power value of the APD system
The bell is assumed to be fake and the input power value is low.
Bias control only when wireless standard Q1 is satisfied
To reduce current consumption. FIG. 4A shows a power amplifier as shown in FIG.
4 when the bias control of the power amplifier 4 is performed.
An example of the bias value controlled with respect to
And the bias control of the power amplifier 4 as in the prior art.
Is not controlled for power amplifier 4 when
An example of the bias value used is shown as Q12.
In addition, the bias control of the power amplifier 4 is performed as in this example.
Of the current consumed by the power amplifier 4 when
The power amplifier 4 is shown as Q13.
Power amplifier 4 when the bias control of
Is shown as Q14. This
Here, the horizontal axis of the graph indicates the input power value of the power amplifier 4.
The vertical axis on the right shows the bias value of the power amplifier 4.
The vertical axis on the left shows the current consumed by the power amplifier 4.
Is shown. FIG. 4B shows the input of the power amplifier 4.
Power Power Range A, B, C (C <B <A) and Power Amplifier
4, the bias values A ', B', C '(C'
<B ′ <A ′), and shows an example of a correspondence relationship with the present example.
Then, such a correspondence is stored in the storage circuit 1 as a table.
6 is set. In the conventional example, the input of the power amplifier is
A constant bias value A 'is always constant regardless of the power value.
Supplied to the amplifier. In this example, the input power of the power amplifier 4 is
Divide the value into three ranges A, B, C for each range A, B, C
The bias value of the power amplifier 4 is changed.
For example, the width of the input power value range should be narrowed.
With this, the current consumption is smoother with less steps.
Control becomes possible. Further, for example, the power amplifier 4
If the input power value of
Configuration in which the bias value of power amplifier 4 is changed for each band
Can also be used. As shown in FIG. 4A, as shown in FIG.
When the bias control of the power amplifier 4 is performed during
In the range B, the current consumed by the power amplifier 4 is larger than that in the range A.
Can be reduced, and in the range C of the input power value,
The current consumption by the power amplifier 4 is reduced as compared with the range B.
be able to. In addition, as an example of a specific effect,
If the current consumption of the amplifier 4 is set too low, the amplifier will oscillate.
Bias control was performed taking into account
As a result, the current consumption is 5.6 A in the conventional example at the time of low traffic.
Was about 3.3 A in the range of the wireless standard in this example.
It has been confirmed that current consumption can be suppressed
In this case, the current consumption is reduced by about 40%.
You. FIG. 5 shows one of the wireless standards related to the wireless characteristics.
An example is shown as Q21, and a power amplifier as in this example
Of the wireless characteristics when the bias control of FIG.
An example is shown as Q22, and power amplification is performed as in the conventional example.
Characteristics when bias control of the device 4 is not performed
Is shown as Q23, and as in this example,
When the bias control of the power amplifier 4 is performed,
An example of the power consumption of the power amplifier 4 is shown as Q24.
Thus, the bias control of the power amplifier 4 is performed as in the conventional example.
An example of the power consumption of the power amplifier 4 in the case where
25. Here, the horizontal axis of the graph shows the power increase.
The input power value of the band 4 is shown.
The vertical axis on the right shows the power consumption of the power amplifier 4.
Is shown. As described above, in this example, the wireless
The ACLR is used as the property. As shown in FIG.
When the bias control of the amplifier 4 is performed, the bias control is performed.
ACLR characteristics are degraded compared to the case where
However, at the stage of the input power value ranges B and C shown in FIG.
Are controlled so as to satisfy the wireless standard Q21.
And the power consumed by the power amplifier 4
Can be reduced. As described above, the APD system distortion compensation of this embodiment
In the amplifier, the input signal level for detecting the level of the input signal is
Bell detection function 6 and a plurality of input signal level ranges A, B,
C and the plurality of input signal level ranges A, B, C
Bias control values A ', B', and C 'are stored in association with each other.
Storage function 16 and a control function 15.
Signal level detection function 16
By the storage function 16 according to the detected input signal level,
Read the bias control value and read the bias control value
Is applied to the power amplifier 4. As described above, the APD distortion compensation of the present embodiment is increased.
The width device automatically controls the distortion compensation by the APD method.
When performing, adjacent channel leakage at low power level
There is a margin for wireless standards such as power (ACLR)
Noting that, it is stored for bias control of the power amplifier 4.
A circuit 16 and a D / A converter 17;
Monitor the value to determine the adjacent channel leakage power at low power levels.
Control the bias of the power amplifier 4 to such an extent that
The power consumption of the power amplifier 4 is controlled to be low.
Therefore, the power in the distortion compensation amplification circuit using the APD method
The current consumption of the amplifier 4 (amplifier current) can be limited.
As a result, the power consumption of the power amplifier 4 can be reduced.
Can be planned. Here, when the output level is low, for example,
This corresponds to low traffic at midnight or the like.
Traffic volume and the detected traffic
A structure for controlling the bias of the power amplifier 4 according to the amount.
It is also possible to make it. In the APD method,
Originally, low power consumption was achieved, but in this example,
Power consumption can be improved, and as described above, wireless characteristics
The amplifier as a whole while satisfying the
Power consumption can be kept low. Also, this example
As described above, the input power value of the power amplifier 4 is set to a plurality of ranges A, B,
In a configuration in which control is performed separately for C, for example, software
It is possible to simplify the control using air. Here, as the power amplifier 4, for example,
It can also be composed of a number of amplification elements, in which case
The bias of these multiple amplifying elements can be controlled collectively.
To simplify the control, or
Fine control by individually controlling the bias of the amplifier
For example, bias control can be performed. Also book
An example of an APD distortion compensation amplification device is a wireless
Function to amplify the signal transmitted by
Wireless transmission / reception amplification device that has the function of amplifying transmitted signals
It is possible to apply to. In this embodiment, the function of the power amplifier 4
The amplifier described above is constituted, and the function of the power measuring device 6 is
Constitutes a signal level detecting means according to the present invention.
Data processor 15, storage circuit 16, D / A converter 1
By the function of 7, the amplifier bias control means of the present invention is
It is configured. In this example, the function of the storage circuit 16 is
Constitute a bias control value storage means. Next, a second embodiment according to the present invention will be described.
Adapter using baseband signal input method to which the present invention is applied
Active pre-distortion (APD) distortion compensation increased
An example of the width device will be described. FIG. 6 shows the base according to this example.
APD system distortion compensation amplifier using band signal input system
Is shown. With baseband signal input method
Handles baseband signals as distortion compensation signals.
U. In this example, baseband signals of a plurality of channels are used.
For example, four channels
And sum the baseband signals of Ch1 to Ch4 and transmit
An elephant is shown. The APD type distortion compensating and amplifying device of this embodiment includes:
Four carrier offset units C1 to C4 and an addition circuit 3
1, the complex multiplier 32, the D / A converter 33,
Width modulator (QAM MOD) 34 and local signal generator 3
5, a multiplication circuit 36, a power amplifier (PA) 37,
Directional coupler 38 and logarithmic amplifier (LOG AMP) 51
And a power measuring device 39 having an A / D converter 52 and storage
A circuit 40, a local signal generator 41, a multiplication circuit 42,
Band pass filter 43, A / D converter 44, data
The processing unit 45, the storage circuit 46, and the D / A converter 47
Provided. Here, the APD distortion compensation amplifier of the present embodiment is used.
The configuration of the device is, for example, the APD type distortion compensation shown in FIG.
Component parts C1 to C4, 31 to 45 similar to the amplifying device,
51 and 52 for bias control of the power amplifier 37
Having a storage circuit 46 and a D / A converter 47
In this example, the radio
Power amplifiers
Radio characteristics such as the level of distortion generated in 37
Optimize bias control at a point that satisfies
Do that. Here, as the wireless characteristics, for example, CDM
Adjacent channel leakage power when communicating A signal
(ACLR). With the APD system distortion compensating and amplifying device of this embodiment,
An example of the operation to be performed will be described. APD system distortion compensation of this example
In the amplifying device, a key is set for each signal of each channel Ch1 to Ch4.
Carrier offset units C1 to C4, for example,
After shifting the numbers, the four carrier offset devices C1 to C1
The signals output from C4 are summed by the adder circuit 31
You. Here, each carrier offset device C1 to C4 and
The data processing unit 45 performs information on the carrier (key).
Information such as frequency is input as carrier information).
You. The signal of the sum result output from the addition circuit 31
The signal is input to the complex multiplier 32, and the complex multiplier 32
After the amplitude and phase of the signal are controlled,
The converted signal is D / A converted by the D / A converter 33.
Modulated by the quadrature amplitude modulator 34. The modulated
The signal is output from the local signal generator 35 in the multiplication circuit 36.
Multiplied (mixed) with a signal of a given frequency (local frequency)
) To obtain a signal in the radio frequency band, and the result of the multiplication is
The signal amplified by the power amplifier 37 and in the radio frequency band
Is output. The signal output from the addition circuit 31
A part is input to the power measuring device 39 via, for example, a directional coupler.
Is forced. In the power meter 39, the input signal is logarithmically
The signal is amplified by an amplifier 51 and the result of the amplification is converted to an A / D converter.
Digital data (data) obtained by A / D conversion
Digital value) as the measured power value of the signal.
Output to the processing unit 45. The data processing unit 45 includes the digital
Capture the data. Then, under the control of the data processing unit 45,
The signal power value obtained by the power measuring device 39 is used as an address.
Then, the address stored in the complex control storage circuit 40 is stored.
The complex control value corresponding to the
Is supplied to the complex multiplier 32. In the complex multiplier 32,
Use the gain and phase change amount according to the input complex control value.
And performs signal level control and phase control. The signal output from the power amplifier 37
Is input to the multiplication circuit 42 through the directional coupler 38.
Is done. Local signal generator 41 receives data from data processing unit 45
Signal of a predetermined frequency (local frequency)
Then, the signal is output to the multiplication circuit 42. Multiplication circuit 4
2, the signal input from the directional coupler 38 and the local signal
The signal input from the signal generator 41 is multiplied (mixed).
You. The multiplication result is band-controlled by the band-pass filter 43.
The signal after the band limitation is applied to the A / D converter 44.
The data is then A / D converted and taken into the data processing unit 45. Here, as the band-pass filter 43,
A signal is generated due to nonlinear distortion in the power amplifier 37.
Out of the band.
Ruta is used. Also, the local signal generator 41
Out-of-band spectral components
It is controlled so as to generate a signal of such a frequency. Soshi
The data processing unit 45 passes through the bandpass filter 43.
Level of the input signal, that is,
Out-of-band spectrum generated by the signal due to nonlinear distortion
Operate according to an algorithm that minimizes the
You. Specifically, the data processing unit 45 performs such non-linear processing.
To minimize the effects of shape distortion,
The storage contents (control values) of the path 40 are determined by trial and error. The storage circuit 46 stores the power
The signal level detected by the
When the level is detected, the bias of the power amplifier 37 is changed.
The control value used for control is stored. Where the signal
As a bias control value corresponding to the level, for example,
Wireless characteristics such as the level of distortion generated by the power amplifier 37
Is within the range that meets the ACLR standard and the power is increased.
The control value is set so that the power consumed by the
Is determined. The data processing section 45 controls the storage circuit 46.
To add the signal level detected by the power meter 39.
The control value corresponding to the address is stored in the memory 4
6 to the D / A converter 47. The control value is
From digital value to analog signal by D / A converter 47
It is converted and input to the bias control terminal of the power amplifier 37.
You. The power amplifier 37 receives the input to the bias control terminal.
The bias is controlled by the analog signal (the control value).
To perform an amplification operation. The APD distortion compensation amplifier of this embodiment
Also, for example, with reference to FIGS.
In the same manner as described above, the bias control of the power amplifier 37 is performed.
Control is performed. Then, the APD distortion compensation amplification of this example
In the apparatus, for example, the same as described in the first embodiment is used.
Such a low power consumption effect can be obtained. In this example, the function of the power amplifier 37
An amplifier according to the present invention is configured, and the power measuring device 39
The function constitutes a signal level detecting means according to the present invention.
Data processing unit 45, storage circuit 46, D / A conversion
Amplifier 47 control means according to the present invention by the function of
A step is configured. In this example, the storage circuit 46
The function constitutes a bias control value storage means. Here, the pre-distortion according to the present invention
The configuration of the distortion type distortion compensation amplifier
Not limited to those shown above, various configurations may be used.
Is also good. In the present invention, for example, the processing according to the present invention is performed.
And how to implement such a method.
It can be provided as a ram or the like. In addition,
The fields of application of the above are not necessarily limited to those listed above.
However, the present invention can be applied to various fields.
Things. It should be noted that the present invention, for example,
Instead, for example, TDMA (Time Division Multiple A)
ccess) or FDMA (Frequency Division Multiple
Access) and other communication devices and communication systems.
It is also possible to apply to any. The pre-distortion according to the present invention
Various processing performed in the system distortion compensation amplification device, etc.
Hardware, such as a processor or memory
In hardware resources, the processor uses ROM (Read Only Me
mory) by executing the control program
A controlled configuration may be used, and for example,
Each function means for executing the processing is independent hardware.
It may be configured as an air circuit. In addition, the present invention
Floppy (registered trademark)
Computers such as disks and CD (Compact Disc) -ROM
Storage media that can be read by
The control program can be grasped as
Input from recording medium to computer and execute on processor
Cause the processing according to the present invention to be performed.
Can be. As described above, according to the present invention,
According to the distortion type distortion compensation amplification device, the transmission
When the target signal is amplified by the amplifier
When compensating for the distortion that occurs in the previous stage of the amplifier,
The level of the signal amplified by the amplifier is detected and detected.
The level of distortion generated by the amplifier when the signal level is low.
That the bell falls below the specified distortion level
To reduce the power consumed by the amplifier.
Since the bias of the amplifier is controlled, the amplifier
The level of distortion caused by
The power consumed by one amplifier is lower than conventional
It can be powered.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating an example of a distortion compensation amplification device using an adaptive pre-distortion method using a wireless signal input method according to a first embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a procedure of a process of changing a bias of a power amplifier. FIG. 3 is a diagram illustrating an example of radio characteristics (ACLR) when bias control of a power amplifier is performed and not performed. FIG. 4 is a diagram illustrating an example of current consumption of the power amplifier when bias control of the power amplifier is performed and when bias control is not performed. FIG. 5 is a diagram illustrating an example of radio characteristics (ACLR) and an example of power consumption of the power amplifier when bias control of the power amplifier is performed and not performed. FIG. 6 is a diagram illustrating an example of a distortion compensation amplification device using an adaptive pre-distortion method using a baseband signal input method according to a second embodiment of the present invention. FIG. 7 is a diagram illustrating an example of a distortion compensation amplification device using an adaptive predistortion method using a wireless signal input method according to a conventional example. FIG. 8 is a diagram illustrating an example of a distortion compensation amplification device using an adaptive predistortion method using a baseband signal input method according to a conventional example. [Explanation of Signs] N input terminal, 1 delay circuit, 2 gain control circuit, 3 phase control circuit, 4, 37 amplifier
5, 38 directional coupler, 6, 39 power measuring instrument,
7, 9, 16, 40, 46... Memory circuits, 8, 10,
17, 33, 47... D / A converter, 11, 35, 41
..Local signal generators, 12, 36, 42 Multipliers, 13, 43 Bandpass filters 14, 22, 4
4, 52 ··· A / D converter, 15, 45 · · · data processing unit, 21, 51 · · · logarithmic amplifier, C1 ~ C4 · · · carrier offset device, 31 · · · addition circuit, 32 · · · complex multiplication unit 34 ··· Quadrature amplitude modulator,

   ────────────────────────────────────────────────── ─── Continuation of front page    F term (reference) 5J090 AA01 AA41 CA21 CA36 FA10                       GN03 KA00 KA15 KA26 KA32                       KA34 KA44 KA53 KA68 SA14                       TA01 TA02 TA07                 5J092 AA01 AA41 CA21 CA36 FA10                       GR09 KA00 KA15 KA26 KA32                       KA34 KA44 KA53 KA68 SA14                       TA01 TA02 TA07                 5J500 AA01 AA41 AC21 AC36 AF10                       AK00 AK15 AK26 AK32 AK34                       AK44 AK53 AK68 AS14 AT01                       AT02 AT07 RG09                 5K060 BB08 CC04 DD04 HH06 LL11

Claims (1)

Claims: 1. A pre-distortion type distortion compensating amplifier for amplifying a signal to be transmitted by an amplifier in a stage preceding the amplifier when amplifying the signal by the amplifier. Signal level detecting means for detecting the level of the signal; and, when the signal level detected by the signal level detecting means is low, the amplifier ensuring that the level of the distortion generated by the amplifier satisfies a predetermined distortion level condition and becomes low. And a bias control means for controlling the bias of the amplifier so as to reduce the power consumed by the predistortion method.