JP3937399B2 - Adaptive predistortion type multi-port amplifier and transmission apparatus having the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an adaptive predistortion type multi-port amplifier and a transmission apparatus including the same, and for example, a transmission required to output a large transmission power, such as a transmitter of a mobile radio communication system or a satellite communication system. In the apparatus amplifier, the nonlinear distortion of the amplifier is adaptively compensated, and a plurality of amplifiers are used to distribute the power amplification capacity and stabilize the operation.
[0002]
[Prior art]
FIG. 3 shows the configuration of an adaptive predistortion type multiport amplifier. In the predistortion type multipole amplifier, in the predistortion processing unit 100, the distortion compensation signal output from the compensation signal generation unit 19 is added to the baseband signal 1 to be transmitted by the adder 2, and the distortion is compensated. One port of the multi-port amplifier 200 is subjected to quadrature modulation by the modulation unit 3, converted from a digital signal to an analog signal by a digital-analog converter (DAC) 4, and used as a radio frequency (RF) main signal a by the frequency conversion unit 5. (eg No. 1) is inputted to the P _1.
[0003]
Further, another input port (for example, No. 3) P ₃ of the multi-port amplifier 200 receives a transmission signal of another system output from the other system pre-distortion processing unit 300 having the same configuration as the pre-distortion processing unit 100. The main signal c is input. The signal input to the _first port P ₁ of the multiport amplifier 200 is output from the fourth output port P ₄₄ of the final stage of the multiport amplifier 200, and the third port of the multiport amplifier 200 The signal input to the port P ₃ is output from the second output port P _{24 at} the final stage of the multiport amplifier 200.
[0004]
Each signal output from the multiport amplifier 200 is transmitted from the antenna 13 and partly taken out by each directional coupler 12 provided between each antenna 13 and the multiport amplifier 200. Returning to the predistortion processing units 100 and 300, the predistortion processing units 100 and 300 subtract through the frequency conversion unit 14, the intermediate frequency (IF) amplifier 15, the analog-digital converter (ADC) 16, and the quadrature demodulation unit 17. Is input to the device 18. The signal extracted from the directional coupler 12 is called a feedback signal.
[0005]
The subtractor 18 compares the reference signal, which is a baseband signal to be transmitted, with the feedback signal, and outputs an error component (nonlinear distortion component of the multiport amplifier 200). The compensation signal generation unit 19 adaptively controls the amplitude and phase of the distortion compensation signal output so that the level of the error component is minimized, and becomes a distortion compensation signal that is the inverse characteristic of the nonlinear distortion of the multiport amplifier 200. Is output to the adder 2.
[0006]
The adder 2 adds the distortion compensation signal output from the compensation signal generation unit 19 again to the baseband signal to be transmitted. The adaptive predistortion type multi-port amplifier adaptively compensates for the nonlinear distortion of the high-output multi-port amplifier 200 by repeating a series of processes for generating a distortion compensation signal based on the feedback signal in this way. As a result, a transmission signal without distortion is output.
[0007]
Next, the multiport amplifier 200 will be described with reference to FIG. FIG. 4 shows a configuration example of a 4-port 4-output multiport amplifier. As shown in the figure, the multi-port amplifier includes a 90 ° hybrid distributor 6, a high-power amplifier 7, and a 90 ° hybrid synthesizer 8.
[0008]
The main signal a output from the predistortion processing unit 100 described above is input to the first port P ₁ of the 90 ° hybrid distributor 6, and the distributor 6 provides the four ports P ₁₂ and P _{22 in} the second stage. , P ₃₂ , and P _42, and are amplified by the high-power amplifier 7.
[0009]
The signal amplified by the high power amplifier 7 is combined with 90 ° hybrid combiner 8, the input signal a first port P ₁ is output from the fourth port P ₄₄ of the fourth stage. The input signal c of the third port P ₃ is output from the second port P ₂₄ in the fourth stage. This operation will be described below.
[0010]
When the signal a and the signal c are respectively input to the first port P ₁ and the third port P ₃ of the first stage of the distributor 6, the signals of each stage of the multiport amplifier are as follows. . Here, the input signals of the first port P ₁ and the third port of the first stage are represented as s (P ₁ ) and s (P ₃ ), respectively.
[0011]
The output signals of the first to fourth ports in the first stage are represented as s (P ₁₁ ), s (P ₂₁ ), s (P ₃₁ ), and s (P ₄₁ ), respectively. Further, the output signals of the first to fourth ports of the second stage (input signals of the respective ports of the third stage) are respectively expressed as s (P ₁₂ ), s (P ₂₂ ), s (P ₃₂ ), s. It will be expressed as (P ₄₂ ).
[0012]
The output signals of the first to fourth ports in the third stage are represented as s (P ₁₃ ), s (P ₂₃ ), s (P ₃₃ ), and s (P ₄₃ ), respectively. The output signals of the first to fourth ports in the fourth stage are represented as s (P ₁₄ ), s (P ₂₄ ), s (P ₃₄ ), and s (P ₄₄ ), respectively. Then, the signal of each port is expressed as the following equation.
[0013]
s (P ₁ ) = a
s (P ₃ ) = c
s (P ₁₁ ) = (a / √2) ・ j (0) = a ₁・ j (0)
s (P ₂₁ ) = (a / √2) ・ j (-90) = a ₁・ j (-90)
s (P ₃₁ ) = (c / √2) ・ j (0) = c ₁・ j (0)
s (P ₄₁ ) = (c / √2) ・ j (-90) = c ₁・ j (-90)
[0014]
Here, j (0) indicates that the phase delay is 0, and j (−90) indicates that the phase delay is 90 degrees. In the following, j (−180) and j (−270) similarly indicate that the phase delay is 180 degrees and 270 degrees, respectively. Further, since the amplitude change of the signal between the ports is constant when passing through the second and subsequent hybrid circuits, the description of each expression is simplified as follows.
[0015]
s (P ₁₂ ) = a ₂・ j (0) + c ₂・ j (-90)
s (P ₂₂ ) = a ₂・ j (-90) + c ₂・ j (0)
s (P ₃₂ ) = a ₂・ j (-90) + c ₂・ j (-180)
s (P ₄₂ ) = a ₂・ j (-180) ＋ c ₂・ j (-90)
[0016]
Here, when the gain of each of the high-power amplifiers 7 ₁ , 7 ₂ , 7 ₃ , 7 ₄ is G, it is expressed as follows.
s (P ₁₃ ) = G ⁴ a ₃・ {j (0) + j (-180)} + 2G ・ c ₃・ j (-90)
s (P ₂₃ ) = 2G ・ a ₃・ j (-90) + G ⁴ c ₃・ {j (0) + j (-180)}
s (P ₃₃ ) = G ⁴ a ₃・ {j (-90) + j (-270)} + 2G ・ c ₃・ j (-180)
s (P ₄₃ ) = 2G ・ a ₃・ j (-180) + G ⁴ c ₃・ {j (-90) + j (-270)}
[0017]
s (P ₁₄ ) = 0
s (P ₂₄ ) = 4G ・ c ₄・ j (-180)
s (P ₃₄ ) = 0
s (P ₄₄ ) = 4G ・ a ₄・ j (-180)
[0018]
That is, the signals a, b, c, and d are input to the first port P ₁ , second port P ₂ , third port P ₃ , and fourth port P ₄ of the hybrid distributor 6, respectively. Then, the amplified signals are output from the fourth output port P ₁₄ , the second output port P ₂₄ , the third output port P ₃₄ , and the fourth output port P ₄₄ of the fourth stage of the hybrid synthesizer 8, respectively. G ′ · d, signal G ′ · c, signal G ′ · b, and signal G ′ · a are output. Here, G ′ is an amplification factor by the entire multiport amplifier.
[0019]
The adaptive predistortion type amplifier is disclosed, for example, in Patent Document 1 below, and the multiport amplifier is disclosed in Patent Documents 2, 3 below.
[Patent Document 1]
JP 2001-267850 A [Patent Document 2]
JP-T-2001-503937 [Patent Document 3]
Japanese Examined Patent Publication No. 2-44409 [0020]
[Problems to be solved by the invention]
In the multi-port amplifier configured with a 90 ° hybrid circuit as shown in FIG. 4, if any one of the four high-power amplifiers 7 ₁ , 7 ₂ , 7 ₃ , 7 ₄ fails, the final state of the combiner 8 Isolation at the stage output end will deteriorate. As a result, transmission signal components other than the own system are mixed in the feedback signals to the predistortion processing units 100 and 300.
[0021]
In such a case, the compensation signal generator 19 updates the amplitude and phase characteristics of the distortion compensation signal so that the error between the feedback signal and the reference signal is minimized, and reverses the nonlinear distortion of the multiport amplifier 200. If a transmission signal of another system is mixed in the feedback signal, the feedback signal is not a signal representing the distortion characteristic of the multi-port amplifier 200. Therefore, the distortion compensation signal having the opposite characteristic is generated. It becomes impossible to generate a signal, and in the worst case, the adaptive predistortion process diverges, and the distortion of the transmission signal increases conversely, causing a problem that an interference wave is radiated to an adjacent channel.
[0022]
In the present invention, even when one of the high power amplifiers 7 ₁ , 7 ₂ , 7 ₃ , 7 ₄ constituting the multiport amplifier 200 fails, each transmission signal output from the final stage of the multiport amplifier 200 is obtained. It is an object of the present invention to provide an adaptive predistortion type multi-port amplifier that can ensure isolation between the two, prevent divergence of adaptive predistortion processing, and can continue linear amplification.
[0023]
[Means for Solving the Problems]
The adaptive predistortion type multiport amplifier of the present invention (1) compares a transmission signal before amplification with a feedback signal after amplification of the transmission signal, generates a distortion compensation signal that minimizes the error, and A plurality of predistortion processing units for adding a distortion compensation signal to a transmission signal to compensate for nonlinear distortion of the amplifier, and a plurality of high output amplifiers by inputting each transmission signal output from each of the plurality of predistortion processing units A hybrid distributor that divides the output signal of the hybrid distributor, a plurality of high-power amplifiers that amplify the output signal of the hybrid distributor, and a hybrid synthesizer that combines the output signals of the plurality of high-power amplifiers and separates them into the individual transmission signals Even if any of the plurality of high-power amplifiers fails on the output side of the multi-port amplifier. And a isolation retaining means to maintain the iso-configuration, and has a structure to return to the pre-distortion processing unit output signal of the isolation holding means as said feedback signal.
[0024]
(2) The isolation holding unit includes a plurality of hybrid synthesizers and a changeover switch for switching a connection configuration between the plurality of hybrid synthesizers and the multiport amplifier.
[0025]
The transmission apparatus of the present invention (3) compares the transmission signal before amplification and the feedback signal after amplification of the transmission signal, generates a distortion compensation signal that minimizes the error, and generates the distortion compensation signal. A plurality of predistortion processing units that compensate for nonlinear distortion of the amplifier in addition to the transmission signal, and each transmission signal output from each of the plurality of predistortion processing units is input and distributed to a plurality of high output amplifiers A hybrid distributor, a plurality of high-power amplifiers that amplify the output signals of the hybrid distributor, and a hybrid combiner that combines the output signals of the plurality of high-power amplifiers and separates them into the respective transmission signals An isolator that maintains isolation of each individual transmission signal even if any of the plurality of high-power amplifiers fails on the output side of the multi-port amplifier and the multi-port amplifier. And a Deployment holding means, in which an adaptive predistortion type multiport amplifier having the structure to return to the pre-distortion processing unit output signal of the isolation holding means as said feedback signal.
[0026]
(4) The isolation holding unit in the transmission device includes a plurality of hybrid synthesizers and a changeover switch for switching a connection configuration between the plurality of hybrid synthesizers and the multiport amplifier. .
[0027]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show the configuration of the adaptive predistortion type multi-port amplifier of the present invention. In the adaptive predistortion type multiport amplifier shown in FIG. 1 and FIG. 2, components corresponding to those shown in FIG. 3 or FIG.
[0028]
The adaptive predistortion type multiport amplifier according to the present invention includes a change-over switch 9 ₁ , an output switch of a multiport amplifier 200 constituted by a 90 ° hybrid distributor 6 and a 90 ° hybrid synthesizer 8 and a high output amplifier 7. An isolation holding circuit including 9 ₂ , 9 ₃ , 0 ° hybrid synthesizer 10 and 180 ° hybrid synthesizer 11 is added.
[0029]
When each of the high power amplifiers 7 ₁ , 7 ₂ , 7 ₃ , 7 _{4 of the} multi-port amplifier 200 is operating normally, and when any of the high power amplifiers 7 ₁ or 7 ₄ fails, By switching the changeover switches 9 ₁ , 9 ₂ , 9 ₃ so as to have a connection configuration as shown in FIG. 1, it is possible to ensure isolation of transmission signals of each system.
[0030]
When a failure occurs in either the high-power amplifier 7 ₂ or 7 ₃ , the occurrence of the failure is detected by a sensor (not shown), and the changeover switches 9 ₁ , 9 ₂ , 9 ₃ are shown in FIG. By switching so as to obtain the connection configuration as shown, it is possible to ensure isolation of transmission signals of each system.
[0031]
Thus, even if any _{one of} the high-power amplifiers 7 ₁ , 7 ₂ , 7 ₃ , 7 ₄ of the multi-port amplifier 200 fails, the change-over switches 9 ₁ , 9 ₂ , 9 ₃ By switching the connection configuration of each output terminal of the multi-port amplifier 200, the 0 ° hybrid synthesizer 10 and the 180 ° hybrid synthesizer 11, each antenna 13 and the directional coupler 12, a high-power amplifier that has not failed can be obtained. The predistortion processing units 100 and 300 can continue the operation as it is, and can continue the adaptive distortion compensation processing for the non-failed high-power amplifier nonlinear distortion.
[0032]
An example of the operation of the adaptive predistortion type multiport amplifier according to the present invention will be described below. Assume that the transmission signals a and c are input to the first and third input ports P ₁ and P ₃ of the multi-port amplifier 200 from the predistortion processing units 100 and 300, respectively.
[0033]
Here, when all of the four high-output amplifiers 7 ₁ , 7 ₂ , 7 ₃ , and 7 ₄ are operating normally, the 4th output port P ₄₄ of the final stage 4G ₄ · j (− 180), and the 4Gc ₄ · j (−180) signal is output from the second output port P _{24 in} the final stage.
[0034]
Each output signal from the multi-port amplifier 200, a switch changeover switch 9 _1, 9 ₂ shown in FIG. 1, passing through the 0 ° hybrid combiner 10 and Oyobi -180 ° hybrid combiner 11, the transmission signal a ^*, c ^* is returned to the self-predistortion processing units 100 and 300 by the directional coupler 12.
[0035]
Here, if the high-output amplifier ₇₁ fails as an example, the combiner the output port P ₁₄ of 8, P _24, P _34, the signal from each of P ₄₄ is represented by the following equation s (P _14), s (P ₂₄ ), s (P ₃₄ ), s (P ₄₄ ) are output.
s (P ₁₄ ) = G ⁴ a ₄・ j (-180) + G ⁴ c ₄・ (-270)
s (P ₂₄ ) = G ⁴ a ₄・ j (-270) + 3G ・ c ₄・ (-180)
s (P ₃₄ ) = G ⁴ a ₄・ j (-270) + G ⁴ c ₄・ (0)
s (P ₄₄ ) = 3G ・ a ₄・ j (-180) + G ⁴ c ₄・ (-90)
[0036]
As is apparent from the above equation, it is understood that the components of two types of transmission signals a and c of different systems are output to each output port of the final stage of the multiport amplifier 200, and the isolation between the systems deteriorates. Karu.
[0037]
However, by setting the changeover switches 9 ₁ and 9 ₂ to the connection state shown in FIG. 1, the 0 ° hybrid synthesizer 10 has the signals s (P of the first and fourth output ports P ₁₄ and P _{44. 14} ), s (P ₄₄ ) is input, and the signal a ^* output from the 0 ° hybrid synthesizer 10 is as follows, and does not include other system signal components.
a ^* = 4G ⁴ a ₄・ j (-180)
[0038]
Further, the signals s (P ₂₄ ) and s (P ₃₄ ) of the second and third output ports P ₂₄ and P ₃₄ are input to the −180 ° hybrid synthesizer 11, and the −180 ° hybrid synthesizer 11. The signal c ^* output from is as follows and does not include other system signal components.
c ^* = 4G ⁴ c ₄・ j (-180)
[0039]
0 ° signal is output from the hybrid combiner 10 a ^*, and -180 ° signal is output from the hybrid combiner 11 c ^*, respectively, by switching switches 9 _third connection state shown in FIG. 1, directional coupler 12 To the local predistortion processing units 100 and 300.
[0040]
As a next operation example will be described with the case where the high-output amplifier 7 ₂ fails. Signals s (P ₁₄ ), s (P ₂₄ ), s (P represented by the following equations from the final stage output ports P ₁₄ , P ₂₄ , P ₃₄ , P ₄₄ of the synthesizer 8 of the multi-port amplifier 200, respectively. ₃₄ ), s ( _P44 ) is output.
[0041]
s (P ₁₄ ) = G ⁴ a ₄・ j (0) + G ⁴ c ₄・ (-270)
s (P ₂₄ ) = G ⁴ a ₄・ j (-90) + 3G ・ c ₄・ (-180)
s (P ₃₄ ) = G ⁴ a ₄・ j (-270) + G ⁴ c ₄・ (-180)
s (P ₄₄ ) = 3G ・ a ₄・ j (-180) + G ⁴ c ₄・ (-270)
[0042]
From the above equation, similarly in the case of this operation example, the components of the two types of transmission signals a and c of different systems are output to each output port of the final stage of the multi-port amplifier 200, and isolation between the systems is performed. It turns out that deteriorates.
[0043]
However, by setting the changeover switches 9 ₁ and 9 ₂ to the connection state shown in FIG. 2, the 0 ° hybrid synthesizer 10 has the signals s (P (2) of the second and third output ports P ₂₄ and P _{34. 24} ), s (P ₃₄ ) is input, and the signal c ^* output from the 0 ° hybrid synthesizer 10 is as follows and does not include other system signal components.
c ^* = 4G ⁴ c ₄・ j (-180)
[0044]
Further, the signals s (P ₁₄ ) and s (P ₄₄ ) of the first and fourth output ports P ₁₄ and P ₄₄ are inputted to the −180 ° hybrid synthesizer 11, and the −180 ° hybrid synthesizer 11. The signal a ^* output from is as follows, and does not include signal components of other systems.
a ^* = 4G ⁴ a ₄・ j (-180)
[0045]
0 ° signal is output from the hybrid combiner 10 c ^*, and -180 ° signal is output from the hybrid combiner 11 a ^*, respectively, by switching switches 9 _third connection state shown in FIG. 2, directional coupler 12 To the local predistortion processing units 100 and 300.
[0046]
Even when a failure occurs in the high-power amplifier 7 ₃ or 7 ₄ , the isolation action works similarly to the above-described operation example, and a feedback signal that does not include other system signal components is fed back to the pre-distortion processing unit of the own system. . In the case where a fault in the high output amplifier 7 ₃ occurs, if the operation example in the case of high-output amplifier 7 ₂ described above fails, the failure in the high output amplifier 7 ₄ occurs, the aforementioned high power amplifier 7 _It operates in the same way as the operation example when ₁ fails.
[0047]
【The invention's effect】
As described above, according to the present invention, by providing a hybrid synthesizer that maintains isolation between transmission signals even if a failure occurs in any of a plurality of high-power amplifiers that constitute a multiport amplifier. In addition, by switching the connection state between the output port of the multi-port amplifier and the hybrid synthesizer according to the failure position of each high-power amplifier, the signal components of other systems are included by maintaining the isolation between the transmission signals. An unreturned feedback signal is fed back to the local predistortion processing unit, the adaptive predistortion processing can be operated normally, linear amplification can be continued, and radiation of jamming waves to adjacent channels can be prevented.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration example of an adaptive predistortion multiport amplifier according to the present invention.
FIG. 2 is a diagram illustrating a configuration example of an adaptive predistortion multiport amplifier according to the present invention.
FIG. 3 is a diagram illustrating a configuration example of an adaptive predistortion type multi-port amplifier.
FIG. 4 is a diagram illustrating a configuration example of a multi-port amplifier.
[Explanation of symbols]
1 Baseband signal 2 Adder 3 Quadrature modulation unit 4 Digital to analog converter (DAC)
5 Frequency converter 6 90 ° hybrid distributor 7 High power amplifier 8 90 ° hybrid synthesizer 9 Changeover switch 10 0 Hybrid synthesizer 11 180 ° hybrid synthesizer 12 Directional coupler 13 Antenna 14 Frequency converter 15 Intermediate frequency (IF ) Amplifier 16 Analog to Digital Converter (ADC)
17 Quadrature Demodulator 18 Subtractor 19 Compensation Signal Generator 20 Local Oscillator 100 Local Predistortion Processor 200 Multiport Amplifier 200
300 Other pre-distortion processing section

Claims (4)

The transmission signal before amplification and the feedback signal after amplification of the transmission signal are compared to generate a distortion compensation signal that minimizes the error, and the distortion compensation signal is added to the transmission signal to reduce the nonlinear distortion of the amplifier. A plurality of predistortion processing units for performing compensation;
A hybrid distributor that inputs each transmission signal output from each of the plurality of predistortion processing units and distributes the transmission signals to a plurality of high output amplifiers; a plurality of high output amplifiers that amplifies an output signal of the hybrid distributor; and A multi-port amplifier having a hybrid synthesizer that synthesizes the output signals of a plurality of high-power amplifiers and separates them into the individual transmission signals;
A plurality of hybrid synthesizers, and an isolation holding means comprising a changeover switch for switching the connection configuration between the plurality of hybrid synthesizers and the output port of the multi-port amplifier ,
Adaptive predistortion type multiport amplifier, characterized by having a structure for feeding back to the pre-distortion processing unit an output signal of the isolation holding means as said feedback signal. The isolation holding means includes a 0 ° hybrid synthesizer and a -180 ° hybrid synthesizer,
The changeover switch connects the first and fourth output ports of the multiport amplifier to the 0 ° hybrid synthesizer, and connects the second and third output ports of the multiport amplifier to the −180 ° hybrid. Or connect the first and fourth output ports of the multiport amplifier to the -180 ° hybrid synthesizer and connect the second and third output ports of the multiport amplifier. The adaptive predistortion type multiport amplifier according to claim 1, wherein the adaptive predistortion type multiport amplifier has a configuration for switching whether to connect to a 0 ° hybrid combiner . The transmission signal before amplification and the feedback signal after amplification of the transmission signal are compared to generate a distortion compensation signal that minimizes the error, and the distortion compensation signal is added to the transmission signal to reduce the nonlinear distortion of the amplifier. A plurality of predistortion processing units for performing compensation;
A hybrid distributor that inputs each transmission signal output from each of the plurality of predistortion processing units and distributes the transmission signals to a plurality of high output amplifiers; a plurality of high output amplifiers that amplifies an output signal of the hybrid distributor; and A multi-port amplifier having a hybrid synthesizer that synthesizes the output signals of a plurality of high-power amplifiers and separates them into the individual transmission signals;
A plurality of hybrid synthesizers, and an isolation holding means comprising a changeover switch for switching the connection configuration between the plurality of hybrid synthesizers and the output port of the multi-port amplifier ,
Transmitting apparatus characterized by having an adaptive predistortion type multiport amplifier having a structure for feeding back to the pre-distortion processing unit an output signal of the isolation holding means as said feedback signal. The isolation holding means includes a 0 ° hybrid synthesizer and a -180 ° hybrid synthesizer,
The changeover switch connects the first and fourth output ports of the multiport amplifier to the 0 ° hybrid synthesizer, and connects the second and third output ports of the multiport amplifier to the −180 ° hybrid. Or connect the first and fourth output ports of the multiport amplifier to the -180 ° hybrid synthesizer and connect the second and third output ports of the multiport amplifier. The transmission apparatus according to claim 3, wherein the transmission apparatus has a configuration for switching whether to connect to a 0 ° hybrid synthesizer .

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