JP4130574B2 - Distortion compensation amplifier - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a distortion compensation amplifying apparatus including a distortion detection loop and a distortion removal loop, and in particular, a distortion capable of accurately controlling vector adjustment in a distortion detection loop even when an input signal fluctuates, for example. The present invention relates to a compensation amplification apparatus.
[0002]
[Prior art]
For example, base station devices and relay devices used in mobile radio systems such as car phone systems and mobile phone systems simultaneously amplify multi-channel radio waves, so that the amplifiers of base station devices and relay devices have considerable linearity. This is required but has limitations. Note that the relay device amplifies radio waves from, for example, the base station device, and transmits the radio waves to the mobile station device.
[0003]
Conventionally, various types of feedforward distortion compensation amplifiers that compensate distortion generated in an amplifier are known (see, for example, Patent Document 1). Such a feed-forward distortion compensation amplifier has a rough configuration in which a distortion detection loop and a distortion elimination loop (distortion compensation loop) are arranged in series. In the distortion detection loop, an input signal is branched. Is amplified by an amplifier, the amplifier output signal is branched, and the branched amplifier output signal and the other input signal branched are mutually inverted and synthesized to produce distortion components generated in the amplifier. The signal is extracted, and in the distortion removal loop, the distortion component signal output from the distortion detection loop and the amplifier output signal are inverted and synthesized to obtain an amplifier output signal from which the distortion component generated in the amplifier is removed. ing.
[0004]
In such a feedforward distortion compensation amplifier, for example, a code division multiple access (CDMA) signal having a signal envelope as shown in FIG. 4 is input, and instantaneous peaks P1, P1 ′ are input to the input signal. Is included as a desired wave, and when a vector suitable for the instantaneous peak power is set, distortion occurs when the power is lower than the peak power. On the other hand, if the vector setting is based on the average power, the time during which the distortion increases can be reduced. However, since the vector setting is inappropriate at the momentary peak power, a very high distortion occurs instantaneously. End up.
[0005]
As an example of the prior art relating to vector adjustment in a distortion detection loop, a conventional distortion compensation amplification apparatus includes a distortion detection loop and a distortion removal loop, and is not a peak among the levels of distortion components detected by the distortion detection loop. The vector adjustment of the distortion detection loop is controlled on the basis of the result of averaging the objects, and thereby, the vector adjustment of the distortion detection loop is controlled with high accuracy (see, for example, Patent Document 2). .)
[0006]
[Patent Document 1]
JP-A-5-315847
[Patent Document 2]
JP 2002-111394 A
[0007]
[Problems to be solved by the invention]
As described in the above conventional example, in the conventional feedforward distortion compensation amplifier, if there is an instantaneous peak in the input signal, normal amplification processing is not performed by this, for example, when used for a base station apparatus or a relay amplification apparatus Has a problem of degrading the quality of wireless communication, and further studies on such a problem have been required.
[0008]
Here, such a problem will be specifically described.
For example, when a multicarrier signal is input to a feedforward distortion compensation amplifier, the input signal may instantaneously generate a peak power that is many times larger than the average power. . Here, FIG. 5 shows a variation example of the level of such a multicarrier signal (in this example, the signal electric field strength) with respect to time, and the horizontal axis in the figure indicates time, and the vertical axis Indicates the electric field strength of the signal.
[0009]
Further, the peak power as described above is generated in relation to factors such as channel multiplicity and input signal level. For example, in the case of a communication signal by a W (Wide Band) -CDMA system, The peak factor occurs with a probability of 10% at approximately 4 dB for one carrier, and with a probability of 0.1% at approximately 10 dB.
[0010]
However, when a signal (for example, a multicarrier signal) input to the feedforward distortion compensation amplifier generates peak power, the distortion detection loop circuit and distortion removal loop circuit are unbalanced due to the nonlinear characteristics of the amplifier. As a result, there is a problem that the distortion component remaining in the amplified signal after distortion compensation output from the feedforward distortion compensation amplifier increases. However, it is very difficult in practice to make the operation of the distortion detection loop and the distortion removal loop follow the instantaneous peak power.
[0011]
The present invention has been made in order to solve such a conventional problem. When compensating for distortion generated in an amplifier having a distortion detection loop and a distortion removal loop, for example, when an input signal fluctuates. Another object of the present invention is to provide a distortion compensation amplifying apparatus capable of accurately controlling vector adjustment in a distortion detection loop.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, in the distortion compensation amplifying apparatus according to the present invention, in the distortion detection loop, a signal is distributed, and one distributed signal is vector-adjusted by a vector adjusting means and amplified by an amplifier. A configuration in which a distortion component generated in the amplifier is detected by combining a part of the signal and the other distribution signal and the distortion component detected in the distortion detection loop is removed from the other part of the amplified signal in the distortion removal loop Then, the following processing is performed.
[0013]
That is, the distortion component level information acquisition unit acquires information on the level of the distortion component detected in the distortion detection loop, and the distortion component level change information acquisition unit acquires information on the variation in the level of the distortion component detected in the distortion detection loop. get. Then, the distortion detection loop vector adjustment control unit performs vector adjustment by the vector adjustment unit of the distortion detection loop based on the information acquired by the distortion component level information acquisition unit and the information acquired by the distortion component level fluctuation information acquisition unit. Control.
[0014]
Therefore, the vector adjustment in the distortion detection loop is controlled by controlling the vector adjustment in the distortion detection loop based on the level of the distortion component detected in the distortion detection loop and the fluctuation thereof, for example, even when the input signal fluctuates. Can be accurately controlled.
[0015]
Here, various signals may be used as signals processed by the distortion compensation amplification device.
In vector adjustment, for example, adjustment is performed by changing one or both of the amplitude and phase of a signal.
Further, the vector adjustment means can be constituted by a vector adjuster capable of variably changing the amplitude and phase of the signal, for example, and can variably change the amplitude of the signal, for example. A variable attenuator and a variable phase shifter capable of variably changing the phase of a signal can be combined.
[0016]
Various amplifiers may be used as the amplifier, for example, a power amplifier is used.
Further, the number of amplifiers may be one or plural.
Further, as the part of the amplified signal by the amplifier and the other part of the amplified signal, various parts may be used for the ratio of the part or the other part.
[0017]
In addition, as a mode of combining a part of the amplified signal by the amplifier and the other distributed signal, for example, a mode in which the components of the other distributed signal are combined so as to have a phase (antiphase) different by 180 degrees with the same amplitude, An embodiment close to this is preferably used.
Various accuracy may be used as the accuracy of removing the distortion component from the amplified signal (other portion) by the amplifier, that is, the accuracy of distortion compensation to the extent that is practically effective.
Various configurations may be used as the strain detection loop and the strain removal loop.
[0018]
Various levels of distortion components may be used. For example, a power level or an amplitude level can be used.
Various information may be used as the information regarding the level of the distortion component. For example, the maximum value of the level of the distortion component based on the level of the distortion component detected a plurality of times is used as the information regarding the level of the distortion component. A mode in which the average value of the distortion component level is acquired as information on the level of the distortion component based on the mode to be acquired, the distortion component level detected a plurality of times, or a distortion based on the level of the distortion component detected a plurality of times A mode in which the weighted average value of the component levels is acquired as information on the level of the distortion component, a mode in which two or more of these are acquired, and the like can be used. Note that various times may be used as the plurality of times.
[0019]
Various information may be used as the information regarding the fluctuation of the distortion component level. For example, the average value of the distortion component level is calculated based on the distortion component level detected a plurality of times. A mode in which the result obtained by dividing by the maximum value is acquired as information on fluctuations in the level of the distortion component, or the maximum value of the distortion component level is multiplied by a predetermined value less than 1 based on the level of the distortion component detected multiple times. For example, a mode in which the ratio of the level of the distortion component that is greater than or equal to (or exceeds the value) is acquired as information on the fluctuation of the distortion component level can be used. Note that various times may be used as the plurality of times. Various values may be used as the predetermined value that is less than 1.
[0020]
Further, as one configuration example, the distortion component level variation information acquisition unit includes a distortion component level detected once or a plurality of times used by the distortion component level information acquisition unit, and information acquired by the distortion component level information acquisition unit. The information regarding the fluctuation | variation of the level of the distortion component detected in a distortion detection loop is acquired using one or both of these. That is, independent processing may be performed by the distortion component level information acquisition unit and the distortion component level variation information acquisition unit, but it is more efficient and preferable to perform common processing in common.
[0021]
Various modes may be used as a mode of controlling the vector adjustment in the strain detection loop by the strain detection loop vector adjustment control means. For example, a mode of controlling so as to improve the accuracy of strain detection by the strain detection loop. Is used.
As one configuration example, the distortion detection loop vector adjustment control unit controls the distortion component detected in the distortion detection loop to be small, and as a preferred embodiment, the distortion detection loop magnitude detected by the distortion detection loop. Is controlled to be minimum.
[0022]
Note that the magnitude of the distortion component detected in the distortion detection loop is acquired by, for example, the distortion component level detected by the distortion detection loop or an average value thereof, or the distortion component level information acquisition unit. A value related to the magnitude of the distortion component can be used.
[0023]
In addition, in the distortion compensation amplifying apparatus according to the present invention, the following processing is performed as a configuration example.
In other words, the distortion component level information acquisition unit has a distortion component level detection unit that detects the level of the distortion component detected in the distortion detection loop, and detects a value based on the detection result obtained by the distortion component level detection unit a plurality of times. Acquired as information on the level of the distortion component detected in the loop. Further, the distortion component level fluctuation information acquisition means uses a threshold value based on a result of detecting the distortion component level detected in the distortion detection loop a plurality of times, and the distortion component level detected in the distortion detection loop is equal to or higher than the threshold value. The ratio value or the ratio value exceeding the threshold value is acquired as information relating to fluctuations in the level of the distortion component detected by the distortion detection loop. Further, the distortion detection loop vector adjustment control unit uses the control amount based on the value acquired by the distortion component level information acquisition unit and the value acquired by the distortion component level fluctuation information acquisition unit, and the vector adjustment unit of the distortion detection loop Controls vector adjustment by.
[0024]
Here, various values may be used as a value based on a plurality of detection results by the distortion component level detection means.
Various times may be used as the plurality of times.
Various values may be used as the threshold based on the result of detecting the level of the distortion component detected in the distortion detection loop a plurality of times.
Various times may be used as the plurality of times.
Further, as the plurality of times, for example, a set number of times may be used, or the number of times detection processing is performed within a set time may be used.
[0025]
Various control amounts based on the value acquired by the distortion component level information acquisition unit and the value acquired by the distortion component level variation information acquisition unit may be used.
As one configuration example, the distortion detection loop vector adjustment control means includes a correspondence between the level of the distortion component detected by the distortion detection loop and the vector adjustment amount in the vector adjustment means of the distortion detection loop, or the distortion component level information acquisition means. The correspondence between the acquired value and the vector adjustment amount in the vector adjustment means is stored. Then, based on the stored contents, the distortion detection loop vector adjustment control means corresponds to the vector adjustment amount corresponding to the level of the distortion component detected by the distortion detection loop or the value acquired by the distortion component level information acquisition means. Vector adjustment by the vector adjustment unit of the distortion detection loop is controlled using a control amount corresponding to the result obtained by multiplying the vector adjustment amount by the value acquired by the distortion component level variation information acquisition unit.
[0026]
As one configuration example, the distortion component level information acquisition unit acquires the maximum value of the distortion component level from the result of detecting the distortion component level detected in the distortion detection loop a plurality of times. Further, the distortion component level variation information acquisition unit uses the result obtained by multiplying the maximum value of the distortion component level acquired by the distortion component level information acquisition unit by a predetermined value less than 1 as a threshold, and detects distortion. A value of a ratio at which the level of the distortion component detected in the loop is equal to or greater than a threshold value is acquired. The distortion detection loop vector adjustment control means stores the correspondence between the value acquired by the distortion component level information acquisition means and the vector adjustment amount in the vector adjustment means of the distortion detection loop, and is acquired by the distortion component level information acquisition means. The vector adjustment by the vector adjustment unit of the distortion detection loop is controlled using the control amount corresponding to the result obtained by multiplying the vector adjustment amount corresponding to the value obtained by the value acquired by the distortion component level variation information acquisition unit. Various values may be used as the predetermined value less than 1.
[0027]
The distortion compensation amplifying apparatus according to the present invention is provided in, for example, a wired or wireless transmitter or a wired or wireless communication apparatus, and amplifies a signal to be transmitted by an amplifier of a distortion detection loop. Compensate for the distortion that occurs.
Here, the wired or wireless communication device is provided in, for example, a wired or wireless communication system.
[0028]
The distortion compensation amplifying apparatus according to the present invention is provided in a base station apparatus or a relay station apparatus of a wireless communication system such as a car phone system, a mobile phone system, or a simple mobile phone system (PHS). It is done.
Various transmitters, communication devices, communication systems, base station devices, and relay station devices may be used.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment according to the present invention will be described with reference to the drawings.
FIG. 1 shows an example of a feedforward type distortion compensation amplifying apparatus according to an embodiment of the present invention.
The distortion compensation amplification device of this example includes a distortion detection loop, a distortion removal loop, and a control unit.
[0030]
The distortion detection loop circuit includes a vector adjuster 3, a main amplifier 4, and a delay line 5 provided between the directional coupler 2 and the directional coupler 6. When amplifying, a distortion component generated in the amplifier 4 is detected. In the main amplifier 4, distortion such as intermodulation distortion occurs.
The circuit of the distortion removal loop includes a delay line 7, a vector adjuster 8, and an auxiliary amplifier 9 provided between the directional coupler 6 and the directional coupler 10, and is detected by the distortion detection loop. The distortion component is removed from the amplified signal by the main amplifier 4.
[0031]
The control circuit includes an input level detector 1, an A / D (Analog to Digital) converter 17, a pilot signal generator 11, a combiner T1, a combiner T2, a pilot receiver 12, and an A / D converter 13, coupler T 3, amplifier 14, detector 15, A / D converter 16, D / A (Digital to Analog) converter 18, D / A converter 19, The control circuit 20 is configured to control a distortion detection loop and a distortion removal loop.
[0032]
Below, an example of the operation | movement performed by each process part 1-20 and T1-T3 is shown.
In the distortion compensation amplifier of this example, for example, a channel-multiplexed modulation signal or the like is input to the input level detector 1 as a signal to be amplified. Then, the input signal is input to the directional coupler 2 of the distortion detection loop via the input level detector 1.
[0033]
In the distortion detection loop, the directional coupler 2 distributes the signal output from the input level detector 1 into two signals, and the vector adjuster 3 adjusts the amplitude and phase of one of the distribution signals, and after the adjustment. The main amplifier 4 amplifies one of the distributed signals. Then, the pilot signal generator 11 generates a predetermined pilot signal and couples the pilot signal to the amplified signal output from the main amplifier 4 via the coupler T1, and the amplified signal after the coupling is the directional coupler. 6 is input.
[0034]
In the distortion detection loop, the other distributed signal output from the directional coupler 2 is transmitted through the delay line 5 so that, for example, one distributed signal is processed by the vector adjuster 3 or the main amplifier 4. The other distribution signal delayed by the same time as the delay time is input to the directional coupler 6.
[0035]
The directional coupler 6 synthesizes a part of the amplified signal input from the main amplifier 4 and the delayed signal input via the delay line 5, so that the distortion component included in the amplified signal and The pilot signal components are detected, and these detected components are output to the vector adjuster 8. The directional coupler 6 outputs the remaining portion of the amplified signal input from the main amplifier 4 to the delay line 7.
[0036]
Here, the amplified signal input from the main amplifier 4 to the directional coupler 6 includes an input signal amplified by the main amplifier 4, a distortion component generated by the main amplifier 4, and a combined pilot signal component. It is. The delayed signal input to the directional coupler 6 via the delay line 5 includes a delayed input signal.
In the distortion detection loop, the input signal components included in each of the two signals synthesized by the directional coupler 6 are synthesized with the same amplitude and opposite phase (that is, with a phase shifted by 180 degrees). As described above, the control circuit 20 controls the amplitude and phase adjustment by the vector adjuster 3.
[0037]
In the distortion elimination loop, the remaining part of the amplified signal output from the directional coupler 6 is transmitted through the delay line 7 so that, for example, the signal output from the directional coupler 6 to the vector adjuster 8 is The amplified signal delayed by the same time as the delay time caused by processing by the vector adjuster 8 and the auxiliary amplifier 9 is input to the directional coupler 10.
[0038]
In the distortion removal loop, the vector adjuster 8 adjusts the amplitude and phase of the signal output from the directional coupler 6 to the vector adjuster 8, and the auxiliary amplifier 9 amplifies the adjusted signal to The amplified signal is output to the directional coupler 10.
[0039]
Then, the directional coupler 10 combines the amplified signal input via the delay line 7 and the signal input from the auxiliary amplifier 9 so that the distortion component and the pilot signal component included in the amplified signal are obtained. The signal after removal is output. The output signal from the directional coupler 10 becomes an output signal from the distortion compensation amplification device of this example.
[0040]
Here, the amplified signal input to the directional coupler 10 via the delay line 7 includes an input signal amplified by the main amplifier 4, a distortion component generated by the main amplifier 4, and a combined pilot signal component. Is included. The signal input from the auxiliary amplifier 9 to the directional coupler 10 includes an amplified distortion component and an amplified pilot signal component.
In the distortion removal loop, pilot signal components (same for distortion components) included in each of the two signals synthesized by the directional coupler 10 are synthesized with the same amplitude and in opposite phases. Adjustment of the amplitude and phase by the vector adjuster 8 is controlled by the control circuit 20.
[0041]
The input level detector 1 is provided before the distortion detection loop (directional coupler 2), detects the level of the input signal, and outputs the detection result to the A / D converter 17 as an analog signal. The input signal is output to the directional coupler 2. The detection result input to the input level detector 1 to the A / D converter 17 is converted into a digital signal by the A / D converter 17 and input to the control circuit 20.
[0042]
The pilot receiver 12 inputs a part of the amplified signal after distortion compensation (after distortion removal) output from the distortion removal loop (directional coupler 10) via the coupler T2, and is included in the inputted signal. The detected pilot signal component is detected, and the detection result is output to the A / D converter 13 as an analog signal. The detection result input from the pilot receiver 12 to the A / D converter 13 is converted into a digital signal by the A / D converter 13 and input to the control circuit 20 as a pilot signal component electric field level.
[0043]
The amplifier 14 inputs a part of a signal (a signal including a distortion component) output from the (directional coupler 6) of the distortion detection loop to the vector adjuster 8 of the distortion removal loop via the coupler T3. The input signal is amplified and output to the detector 15. The detector 15 detects the amplified signal input from the amplifier 14 and outputs the detection result to the A / D converter 16 as an analog signal. The detection result input from the detector 15 to the A / D converter 16 is converted into a digital signal by the A / D converter 16 and input to the control circuit 20 as a distortion component electric field level.
[0044]
The control circuit 20 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). Then, for example, with respect to the vector adjuster 3 of the distortion detection loop, the control circuit 20 adjusts the vector adjuster so that the distortion component electric field level input from the A / D converter 16 is small (preferably minimized). 3 outputs a digital control signal for controlling the adjustment of the amplitude and phase by 3 to the D / A converter 18. The digital control signal input from the control circuit 20 to the D / A converter 18 is converted into an analog control signal by the D / A converter 18 and input to the vector adjuster 3, and accordingly, according to the analog control signal. Thus, the amplitude and phase adjustment by the vector adjuster 3 is controlled. Note that reducing the distortion component electric field level corresponds to, for example, reducing the input signal component remaining in the distortion component (and pilot signal component) detected in the distortion detection loop.
[0045]
Further, the control circuit 20 adjusts the vector adjustment so that the pilot signal component electric field level input from the A / D converter 13 becomes small (preferably, minimum) for the vector adjuster 8 of the distortion removal loop, for example. A digital control signal for controlling adjustment of amplitude and phase by the device 8 is output to the D / A converter 19. The digital control signal input from the control circuit 20 to the D / A converter 19 is converted into an analog control signal by the D / A converter 19 and input to the vector adjuster 8, and accordingly, according to the analog control signal. Thus, the amplitude and phase adjustment by the vector adjuster 8 is controlled. Note that reducing the pilot signal component electric field level corresponds to, for example, reducing the remaining pilot signal component (same for distortion component) in the amplified signal after distortion compensation output from the distortion removal loop.
[0046]
Next, an example of the operation for controlling the vector adjustment by the vector adjuster 3 of the distortion detection loop by the distortion compensation amplification apparatus of this example will be described in more detail.
The control circuit 20 converts the distortion component electric field level (detection power) detected by the detector 15, that is, the electric field level of the distortion component detected by the distortion detection loop, through the A / D converter 16, for example, at regular time intervals. The voltage value is read out, and the voltage value is stored as distortion component level data in a save table provided in the RAM of the self (the control circuit 20).
[0047]
Here, FIG. 2 shows an example of the save table.
In the save table shown in the figure, the distortion component level data detected by the i-th sampling (“i-th level”) from the distortion component level data detected by the first sampling (“first level”). ”) Are stored in order. Here, i represents a plurality of values.
[0048]
Note that the number of times of sampling or the time for performing sampling is preferably set to the number of times or time at which the level fluctuation of the input signal can be sufficiently detected, for example. In other words, when the level of the distortion component is sampled, for example, as shown in FIG. 5 above, instantaneous peak power is irregularly generated in the sampled data. Therefore, by adjusting the number or time of sampling, It is possible to adjust the rate at which the instantaneous peak power is detected.
[0049]
Next, an example of a processing procedure for calculating a control amount for the vector adjuster 3 of the distortion detection loop by the distortion compensation amplifying apparatus of the present example will be described with reference to FIG.
In this process, the control circuit 20 calculates a predetermined distortion amount value and a predetermined distortion fluctuation ratio value based on the level of the distortion component for a plurality of times detected by the distortion detection loop, and calculates the control amount from the calculation result. To do. In this example, the highest level data among the distortion component level data detected by i samplings is used as the distortion amount value. In this example, the ratio of the distortion component level data detected by i times of sampling to the level of 0.8 times or more of the highest level data is set as the distortion fluctuation ratio value.
[0050]
First, the control circuit 20 sequentially reads out the power level of the distortion component detected by the detector 15 as a digital value (A / D conversion value) via the A / D converter 16, and the read distortion component level data. Is stored in the save table (step S1).
Next, the control circuit 20 determines, for example, whether or not the reading of the distortion component level for a predetermined number of times of sampling corresponding to i times of detection or for a predetermined sampling time is completed (step S2). Is determined, the following processing (step S3 to step S10) is executed.
[0051]
That is, first, the control circuit 20 searches for a maximum value from a plurality of (in this example, i) distortion component level values acquired by sampling, and uses the maximum value as the distortion amount value AV1. (Step S3). Here, AV1 = maximum value.
[0052]
Next, for example, according to a preset method, the control circuit 20 distorts the maximum value with respect to the maximum value among a plurality of (i in this example) distortion component level values acquired by sampling. A result value obtained by multiplying the determination magnification by 0.8 is set as a threshold value (distortion fluctuation determination threshold value) AV2 (step S4). Here, AV2 = maximum value × 0.8. In this example, since the maximum value is obtained as the distortion amount value AV1, it is also possible to calculate the value of the distortion variation determination threshold AV2 using this value.
[0053]
Next, the control circuit 20 sequentially compares the magnitudes of each of a plurality (i in this example) of distortion component levels stored in the save table and the distortion fluctuation determination threshold value AV2 obtained as described above. Then, the number of distortion component levels that are equal to or higher than the distortion fluctuation determination threshold AV2 is obtained from the plurality of distortion component levels (steps S5 to S9).
[0054]
Specifically, first, the control circuit 20 stores the number of samplings of the distortion component level (i in this example) in the variable j, that is, j = i, and sets the distortion component level equal to or higher than the distortion variation determination threshold AV2. 0 is substituted into a variable COUNT for counting the number of the number of (step S5).
Next, the control circuit 20 determines whether or not the distortion component level value A (j) detected in the j-th sampling (j = i-th at the first time) is equal to or greater than the distortion fluctuation determination threshold AV2. (Step S6), the variable COUNT is incremented by 1 only when the value A (j) of the distortion component level is equal to or greater than the distortion fluctuation determination threshold AV2 (Step S7).
[0055]
Next, when the determination process (steps S6 and S7) for the distortion component level detected in the j-th sampling is completed as described above, the control circuit 20 decreases the value of j by one. That is, j is updated to (j-1) (step S8), and when j after the update is not 0 (step S9), the same determination process as described above is executed for the updated j ( Step S6, Step S7).
[0056]
In this way, the control circuit 20 performs the same determination process as described above from the distortion component level detected in the sampling number of times (in this example, i) to the distortion component level detected in the first sampling. (Step S6, Step S7) is executed.
[0057]
When the control circuit 20 determines that j is 0, that is, j = 0 (step S9), all (in this example, i times) distortion component levels stored in the save table are determined. Assuming that the above determination processing (step S6, step S7) has been completed, the result obtained by dividing the variable COUNT by the number of times of sampling i is stored in the distortion variation rate value AV3, which is a variable (step S10). Here, AV3 = COUNT / i.
[0058]
Based on the distortion amount value AV1 and the distortion fluctuation ratio value AV3 obtained as described above, the control circuit 20 reduces the distortion amount value AV1, for example, so that it is preferably minimized. The vector adjuster 3 is repeatedly controlled to optimize the vector adjustment (adjustment of signal amplitude and phase) by the vector adjuster 3.
[0059]
Here, an example of how to calculate the control amount for the vector adjuster 3 of the distortion detection loop based on the calculation results of the distortion amount value AV1 and the distortion fluctuation ratio value AV3 will be described.
First, for example, it is assumed that an optimal vector adjustment amount P with respect to the distortion amount value AV1 is obtained based on a result measured in advance when the input signal does not vary. Further, the input signal fluctuates to the optimum vector adjustment amount P ′ for the distortion value AV1 when the input signal fluctuates, and the optimal vector adjustment amount P for the distortion value AV1 when the input signal does not fluctuate. It is assumed that this corresponds to the result obtained by multiplying the distortion fluctuation ratio value AV3 in this case, that is, P ′ = P × AV3.
[0060]
In this case, the control circuit 20 uses the corresponding relationship between the distortion amount value AV1 and the distortion variation ratio value AV3 and the distortion amount value AV1 and the vector adjustment amount P obtained as described above, during vector adjustment. The optimal vector adjustment amount P ′ is calculated, the control amount realized by the calculated vector adjustment amount P ′ in the vector adjuster 3 of the distortion detection loop is calculated, and the distortion detection loop vector is calculated using the calculated control amount. Control for the regulator 3 is performed, thereby realizing suitable control.
[0061]
As the vector adjustment amount, for example, an amplitude adjustment amount and a phase adjustment amount for independently adjusting each of the amplitude and phase of the signal, or an amplitude phase adjustment for collectively adjusting the amplitude and phase of the signal. A quantity is used.
Further, the vector adjustment amount in the vector adjustment performed by the vector adjuster 3 and the control amount given to the vector adjuster 3 in order to realize the vector adjustment amount are associated in advance with the control circuit 20 or the like, for example. Is set.
[0062]
As described above, in the distortion compensation amplification apparatus of this example, when the distortion detection loop amplifies the signal by the main amplifier 4 to detect the distortion component, and the distortion removal loop removes the distortion component from the amplified signal, the detector 15 detects the level of the distortion component detected in the distortion detection loop, and the control circuit 20 calculates the distortion amount value AV1 and the distortion fluctuation ratio value AV3 based on the level of the distortion component detected a plurality of times by the detector 15. Based on the calculation result, the control circuit 20 controls the vector adjuster 3 of the distortion detection loop so as to reduce the distortion amount value AV1, for example.
[0063]
Therefore, in the distortion compensation amplifying apparatus of this example, in the configuration including the distortion detection loop and the distortion removal loop, for example, when the input signal fluctuates, when the input signal fluctuates greatly, Even if the distortion component level fluctuation occurs irregularly, it is provided in the distortion detection loop regardless of the state of the input signal that changes the number of occurrences of distortion component level fluctuation. Thus, the vector adjuster 3 can be controlled with high accuracy, thereby forming a stable distortion detection loop and suppressing the generation of unnecessary distortion components.
[0064]
Further, in the distortion compensation amplifying apparatus of this example, the input signal varies, for example, by controlling the vector adjuster 3 of the distortion detection loop based on the correlation between the obtained distortion amount value AV1 and the distortion variation ratio value AV3. Even when the input signal does not fluctuate, an appropriate vector adjustment can be set in any case.
[0065]
As an example, the distortion compensation amplifying apparatus of this example is configured as a feedforward distortion compensation amplifying apparatus used in a base station apparatus or a relay amplifying apparatus of a wireless communication system. For example, an N (Narrow band) -CDMA system or W Even when a signal having a large peak factor, such as a communication signal by the CDMA system, is amplified, the vector adjuster 3 of the distortion detection loop can be controlled with high accuracy.
[0066]
Here, in this example, the maximum value of the distortion component level detected a plurality of times by the detector 15 is used as the distortion amount value AV1, but as another configuration example, a simple average value or a weight that emphasizes the maximum value is used. Various values relating to the level of the distortion component detected by the distortion detection loop, such as an average value, may be used. Further, as the plurality of times, various times such as 10 times may be used.
[0067]
In this example, as the distortion fluctuation ratio value AV3, a ratio in which the distortion component level is detected by the detector 15 a plurality of times and the distortion component level is equal to or greater than a certain ratio (80% in this example) of the maximum value. However, as another configuration example, there are various values related to fluctuations in the level of the distortion component detected in the distortion detection loop, such as a value obtained by dividing the average value by the maximum value (that is, average value / maximum value). May be used. Further, as the plurality of times, various times such as 10 times may be used.
[0068]
In this example, the level of the signal (input signal) to be amplified by the main amplifier 4 is detected by the input level detector 1. As another configuration example, the signal detected by the input level detector 1 is detected. The distortion amount value AV1, the distortion fluctuation determination threshold value AV2, and the distortion fluctuation ratio value AV3 can be set or adjusted based on the level, whereby the distortion is determined according to the fluctuation of the level of the input signal. It is possible to control the vector adjustment performed in the detection loop.
[0069]
In the distortion compensation amplification apparatus of this example, in the distortion detection loop, a means for distributing a signal is configured by the function of the directional coupler 2, and a vector adjustment means is configured by the function of the vector adjuster 3. The amplifier is configured by the function of the main amplifier 4, and means for detecting a distortion component by synthesizing signals by the function of the directional coupler 6 is configured.
In the distortion compensation amplification apparatus of this example, means for synthesizing signals by the function of the directional coupler 10 and removing distortion components in the distortion removal loop is configured.
[0070]
Further, in the distortion compensation amplifying apparatus of this example, the distortion component level detection means is configured by the function of the detector 15 and the like, and the distortion component level information is acquired by the function of the detector 15 and the control circuit 20 to obtain the distortion value AV1. The acquisition means is configured, and the detector 15 and the control circuit 20 are configured to set a threshold by the function of setting the distortion variation determination threshold AV2, and the detector 15 and the control circuit 20 are configured to have a distortion variation ratio. A distortion component level variation information acquisition unit is configured by the function of obtaining the value AV3, and a distortion detection loop vector adjustment control unit is configured by the function of the control circuit 20 and the like controlling the vector adjuster 3 of the distortion detection loop.
[0071]
Here, the configuration of the distortion compensation amplification device and the like according to the present invention is not necessarily limited to the above-described configuration, and various configurations may be used. The present invention can also be provided as, for example, a method or method for executing the processing according to the present invention or a program for realizing such a method or method. The present invention can also be provided as, for example, a transmitter, a communication device, a base station device, a relay station device, a communication system, and the like.
The application field of the present invention is not necessarily limited to the above-described fields, and the present invention can be applied to various fields.
[0072]
In addition, as various kinds of processing performed in the distortion compensation amplifying apparatus according to the present invention, for example, a processor executes a control program stored in a ROM (Read Only Memory) in a hardware resource including a processor and a memory. May be used, and for example, each functional unit for executing the processing may be configured as an independent hardware circuit.
Further, the present invention can be grasped as a computer-readable recording medium such as a floppy (registered trademark) disk or a CD (Compact Disc) -ROM storing the control program, or the program (itself). The processing according to the present invention can be performed by inputting a program from a recording medium to a computer and causing the processor to execute the program.
[0073]
【The invention's effect】
As described above, according to the distortion compensation amplifying apparatus of the present invention, in the distortion detection loop, the signal is distributed, and one distributed signal is vector-adjusted and amplified by the amplifier, and a part of the amplified signal is When the distortion component generated by the amplifier is detected by combining with the other distribution signal and the distortion component detected by the distortion detection loop is removed from other parts of the amplified signal in the distortion removal loop, the distortion detection loop Information on the level of the distortion component detected in step (b) is acquired, information on fluctuations in the level of the distortion component detected in the distortion detection loop is acquired, and vector adjustment in the distortion detection loop is controlled based on the acquired information. Therefore, for example, even when the input signal fluctuates, vector adjustment in the distortion detection loop can be accurately controlled.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration example of a distortion compensation amplifying apparatus according to the present invention.
FIG. 2 is a diagram illustrating an example of a save table that stores distortion component level data;
FIG. 3 is a diagram illustrating an example of a procedure of processing for calculating a distortion amount value and a distortion variation ratio value used for obtaining a control amount for a vector adjuster 3 of a distortion detection loop, which is performed by a distortion compensation amplification device; .
FIG. 4 is a diagram illustrating an example of a waveform in which peak power such as CDMA is superimposed on an envelope of an input signal.
FIG. 5 is a diagram illustrating an example of fluctuations in the level of a multicarrier signal.
[Explanation of symbols]
1 ... Input level detector 2, 6, 10 ... Directional coupler,
3, 8 ... Vector adjuster, 4 ... Main amplifier, 5, 7 ... Delay line,
9. ・ Auxiliary amplifier, 11. ・ Pilot signal generator,
12 .... Pilot receiver, 13, 16, 17 ... A / D converter,
14 .... Amplifier, 15 .... Detector, 18, 19 .... D / A converter,
20 .. Control circuit,

Claims (1)

Distributes the signal, adjusts one of the distributed signals by vector adjustment means, amplifies it by an amplifier, and combines a part of the amplified signal with the other distributed signal to detect distortion components generated in the amplifier A distortion compensation amplifying apparatus including a distortion detection loop and a distortion removal loop that removes a distortion component detected by the distortion detection loop from another part of the amplified signal;
It has a distortion component level detection means for detecting the level of the distortion component detected in the distortion detection loop, the detection by the distortion component level detection means is performed a plurality of times, and the distortion component level that is the detection result for the plurality of times is detected. Distortion component level information acquisition means for acquiring the maximum value as the distortion amount value AV1 ,
The value obtained by multiplying the maximum value by a predetermined value less than 1 is set as a threshold value AV2, and the level of each of the distortion component levels, which are the detection results for the plurality of times, is compared with the threshold value AV2. Distortion component level fluctuation information acquisition means for acquiring, as a distortion fluctuation ratio value AV3, a value of a ratio that is equal to or greater than the threshold AV2 or a value that exceeds the threshold AV2 with respect to the level of the distortion component that is a detection result of the batch ;
A vector adjustment amount P corresponding to the distortion amount value AV1 is obtained based on a correspondence relationship between the distortion amount value and the vector adjustment amount obtained based on a measurement result performed in advance, and the vector adjustment amount P A value obtained by multiplying the distortion variation ratio value AV3 is set as a vector adjustment amount P ′, and a vector adjustment amount in the vector adjustment by the vector adjustment unit of the distortion detection loop and the vector adjustment unit are realized in order to realize the vector adjustment amount. Based on the association with the given control amount, the control amount to be given to the vector adjustment unit to obtain the vector adjustment amount P ′ is obtained, and the control amount is used by the vector adjustment unit of the distortion detection loop. a distortion detection loop vector adjustment controller for controlling the vector adjuster,
A distortion compensation amplifying apparatus comprising:

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