JPH01260904A - Distortion compensation device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Already Required] Regarding a microwave band distortion compensator placed before a microwave high power amplifier, the distortion signal output from the distortion compensator does not include a component of the microwave signal input. The aim is to automate the adjustment of the phase shifter, and we have developed a branching hybrid that splits the microwave signal input into two, and a shifter that corrects the phase error from the correct phase difference of 90° between the two branched signals. A microwave amplifier that non-shapely amplifies the input signal and generates a distorted signal, an attenuator that adjusts the level, and the correct outputs of both series are input, so that the input microwaves cancel each other out and only the distorted signal is output. and a control signal generator that generates a control signal C according to the level of the microwave signal appearing at its terminal terminal, and the phase shifter controls the phase shifter with the control signal C. The phase shift is configured such that the output level of the terminal terminal of the output side hybrid is maximized.

[Industrial application field]

The present invention relates to a distortion compensator placed before a high-power amplifier for improving the amplitude distortion of a high-power amplifier for a microwave signal having sidebands that is modulated. One side is passed through a microwave signal amplifier and an attenuator that generates a distortion signal S for compensation, and the other is passed through a phase shifter for phase error correction, and then combined again by a branch type vibration lift to generate a distortion signal 13 for compensation. This invention relates to a microwave band distortion compensator that outputs only signals.

[Conventional technology]

Conventionally, as shown in the block diagram of FIG. 3, the above-mentioned microwave band distortion compensator receives a modulated microwave signal input Sin having a carrier frequency wave and a sideband wave, and connects the input end t2 to a resistor R.
Two microwave signals S are input to the input terminal E1 of a branch type hybrid 10Δ terminated by a terminal 1, and the output thereof has an equal amplitude of approximately 1/2 and a phase difference of 90° from each other.
1 and S2, one of which is a phase shifter 11A that adjusts the error from the normal phase difference of 90° between the two series of signals and outputs S1, and the other S2 is a microwave amplifier 218. The signal is non-linearly amplified to generate a distorted signal due to cross-modulation, and the output level thereof is adjusted by a variable attenuator 22A and sent as an S2 output to a branch type hybrid 208 for output. In the output hybrid 208, two series of St ratio outputs 82 outputs with equal amplitude and a correct phase difference of 90° are inputted to the input terminals ti and t2 and synthesized, and from the output terminal L3, the micro The components of the wave signal input Sin are combined in reverse phase and cancel each other out, and only the distorted signal generated by the microwave amplifier 2LA is output as the output signal Sout. The distortion signal, which is the output signal Sout t outputted from this output QN t 3, is applied to a next-stage microwave high power amplifier (not shown) to compensate for the distortion. The other output terminal t4 to the output hybrid 20 is terminated with a resistor R2, and the input terminal tL
If the phase difference between the S1 output and the S2 output of the two series input at t2 is maintained at the normal phase difference of 90°, nothing appears at the output end t4.

[Problem to be solved by the invention]

Microwave signal input Si with the same IOA on the input side
Two series of microwave signals Sl obtained by branching n into two.

S2 is the input end L1. t
2, if the normal phase difference of 90° cannot be maintained and there is a phase error ε, the microwave signals Sl and S2 at the output terminal t3 to the output side hybrid 20 will not be sufficiently canceled, and the output from the output terminal L3 will be insufficient. Since the distorted signal Sout included in the microwave signal input Sin is output, distortion compensation of the microphone and single-wave power amplifier at the subsequent stage cannot be performed properly. To avoid this, the hybrid 20 on the output side
Two series of microwave signals S at the input terminal tLt2 of A
It is necessary to carefully adjust the phase shifter 11Δ so that the phase error ε from the normal phase difference of 90° does not appear between the t output and the S2 output. Observe the output signal of the output terminal t3 of the hybrid 2OA with a spectrum analyzer or the like, change the phase shifter of the phase shifter 11A so that the level of the component of the microwave signal Sin is minimized, and adjust the phase shifter as necessary. Li2 adjustments were made manually by changing the conductor pattern length of the microwave transmission line between the hybrid IOA on the input side and the hybrid 2OA on the output side. Therefore, there is a problem in that it takes time and effort to adjust the phase shifter 11A, which increases the manufacturing cost.

In order to solve this problem, it is an object of the present invention to provide a microwave band distortion compensator in which the adjustment of the phase shifter 11A is automated.

[Failure to solve the problem]

This problem is solved by two series of microwave signals S1, which are branched at the hybrid 10 on the input side of the distortion compensator, as shown in FIG.
Input terminals tl and t2 of the hybrid 20 on the output side of S2
The error ε from the correct phase difference of 90° is the minimum, and the phase difference at
Focusing on the fact that when the component level of the unnecessary microwave signal input Sin at 3 becomes the minimum, the level of the microwave signal Sin at the terminal terminal t4 of the output hybrid 20 becomes the maximum. generates a control signal C according to the output level of the terminal terminal t4 of
The amount of phase shift of the phase shifter 11 is automatically controlled by the control signal C, and the amount of phase shift applied by the phase shifter 11 is equal to '4'! of the output side hybrid 20! : Solved by the present invention, which is characterized in that the output level of the end terminal t4 is given to be maximum.

In the principle diagram of FIG. 1 showing the configuration of the distortion compensator of the present invention, IO is a microwave signal Sin that is modulated and has sidebands.
11 is a first series microwave signal S1 of one of the outputs of the hybrid 10; The phase of the microwave signal 5 is shifted by the control signal C, and there is no phase error ε from the normal phase difference of 90° with the output signal 521c of the other microwave signal S2.
The phase shifter 21 that outputs the input side hybrid 10 outputs the other second series of microwaves (No. 3 S2
A microwave amplifier 22 non-linearly amplifies the output signal 521 to generate distortion and outputs a distorted microwave signal S21; An attenuator 20 outputs a microwave signal 521c having a level equal to the level of the output of the phase shifter 11 and a second series of outputs of the attenuator 22. The first wave signal 521c from the microphone is input to the input terminal LLt2 and synthesized, and the output terminal 3 outputs the distortion signal Sout generated by the microwave amplifier 21 i obtained by reverse phase synthesis. The hybrid 30 on the output side that outputs the microwave signal Sc obtained by dowa synthesis from the terminal terminal t4 is controlled according to the level of the microwave signal Sc output from the terminal terminal t4 of the hybrid 20. This is a control signal generating section that generates signal C.

Then, the phase shift of the phase shifter @l is controlled by the control signal C generated by the control signal generating section 30, and the phase shift imparted by the phase shifter 11 appears at the terminal terminal t3 of the hybrid 20 on the output side. The configuration is such that the output level of the microwave signal Sc is maximized.

[Effect]

The hybrid 10 on the input side inputs a modulated microwave signal Sin having sidebands, splits it into two series of micro-wave signals Sl and S2 of the same level with a phase difference of 90°, and outputs the first series. The signal S1 of the second series is outputted to the phase shifter 11, and the second series signal S2 is outputted to the microwave amplifier 21.

The phase shifter 11 controls the first output of the hybrid 10 on the input side.
The phase of the series microwave signal S1 is shifted by the control signal C, and the microwave signal 5llc, which has no phase error ε from the normal phase difference of 90° with the phase of the output signal 521c of the attenuator 22, is transferred to the hybrid 20 on the output side. Output to.

The microwave amplifier 21 nonlinearly amplifies the second series microwave signal s2 output from the hybrid 10 on the input side, generates a distorted signal, and outputs the distorted microwave signal S21 to the attenuator 22. The attenuator 22 adjusts the level of the output signal 521 of the microwave amplifier 21 and outputs it to the hybrid 20 on the output side as a microwave signal 521c having a level equal to the level of the output signal 5llc of the phase shifter 11.

The hybrid 20 on the output side inputs the microwave signal 521c from the attenuator 22 and the microphone l:1 wave signal 5llc from the phase shifter 11 into its input terminals tl and t2, synthesizes it, and outputs the synthesized signal from its output terminal L3. Distortion signal component Sout obtained by anti-phase synthesis
Let be the output of the distortion compensator of the present invention. Further, the in-phase combined microwave signal Sc is outputted from the terminal terminal t4 and sent to the control signal generating section 30.

The control signal generating section 30 generates a control signal C according to the level of the microwave signal Sc outputted from the termination terminal t4 of the hybrid 2° on the output side, and when the level is at the maximum level, the control signal Co is used to generate the control signal C. The phase shift amount of the phase shifter 11 is determined by two series output microwave signals 5llc and microwave signals 521.
Control is performed to eliminate the phase error of c. As described above, in the distortion compensator of the present invention, the control signal generating section 30 controls the phase shifter 11 using the control signal Co when the microwave signal Sc output from the termination terminal t4 of the hybrid 20 reaches the maximum level.
is controlled to impart a phase shift to the input signal S1 so that the phase error ε between the two series of microwave signals 511c and 521c at the input terminals tl and t2 of the output hybrid 20 is eliminated. The component of the microwave signal input Sin included in the distortion signal output of the distortion compensator of the present invention output from the output terminal t3 of the hybrid 20 becomes the minimum level, and the optimal phase adjustment is automatically performed to solve the problem. .

FIG.

In FIG. 2, the hybrid 10 on the input side is composed of a branch line type hybrid such as a microstrip line, and the input terminal L2 is terminated with a dummy resistor R1, and the input terminal receives a microwave signal subjected to quadrature amplitude modulation QAH as an input signal. t1 and output terminal t3. Phase difference 90 from t4
Two series of microwave signals S1 and S2 with the same level are output at 10°, and the first series of signals Sl has a phase shift of 2″51.
1, and the other second series signal S2 is output to the microwave amplifier 21.

The phase shifter 11 is, for example, a digital type that shifts the phase by sequentially changing a fixed phase step using a switch, and is operated by the control signal C generated by the control signal generator 30 to shift the first series of the output of the hybrid 10. The phase of the microwave signal S1 is shifted to create a correct phase difference 90" from the phase of the output signal 521c of the second series attenuator 22, which will be described later.
and outputs a microwave signal 5llc without error ε.

The microwave amplifier 21 is, for example, a microwave GaA
s It is composed of a PET element, a microstrip line, etc., and a DC bias is selected to perform nonlinear amplification, and the second series microwave signal S2 output from the hybrid 10 is nonlinearly amplified to amplify the input microwave signal S2. At the same time, 3rd and 5th order distortion signals due to cross modulation are also generated,
The microwave signal 521 including the distorted signal is sent to the attenuator 2.
Output to 2. The attenuator 22 consists of a semi-fixed variable resistance attenuator, and the No. 18 S from the microwave signal amplification 2S21
21 to adjust the level of the output signal 5 of the phase shifter 11.
Microwave No. 13 No. 52 with a level equal to the level of LLC.
Let it be 1c.

The hybrid 20 on the output side is the hybrid 1 on the input side.
This is the same branch line type hybrid as 0, but its termination terminal t4 is connected to a Y-shaped curator Yl whose one end is terminated with a dummy resistor R2. Then, the microwave signal 5llc output from the first series phase shifter 11 and the microwave signal 521c output from the second series attenuator 22 are applied to the input terminals tl and t2 of the hybrid 20 at the same level and with the correct phase difference. 90", synthesize it, and output terminal L.
3 and outputs the distorted signal components synthesized in reverse phase from each other to obtain the distortion signal δ output S of the distortion compensator of the present invention.

Let it be ut. In addition, the input terminal El of the hybrid 20, t2
If the input microwave signal Sin is not inputted with a correct phase difference of 90° and is inputted with a phase error ε, a component Sc of the input microwave signal Sin appears at the terminal terminal t4, and is inputted to the input terminal of the Y-shaped curator Y1. Ru. Then, the microwave signal Sc is outputted from the output end of the Y-shaped curator y1 and sent to the control signal generation section 30.

The control signal generation section 30 is composed of a detector 31 and a control section 32, and the detector 31 is connected to the terminal terminal L4 of the hybrid 20.
The microwave signal Sc outputted from the Y-shaped curator Y1 is detected, and the control section 32 generates a control signal C proportional to the detection output level of the detector 31, so that the detection output level reaches the maximum level. The phase shifter 2 with the control signal Co at
Control 1. Then, a phase shift is imparted to the first series of microwave signals S1 from the output end t3 of the hybrid IO, and the input end t1 of the hybrid 2o. The first input to t2
The phase error ε between the series microwave signal Sl lc and the second series microwave signal 521c is made to disappear.

As described above, in the distortion compensator of the embodiment of the present invention shown in FIG. The control signal C output by the control unit 32 at the time
o controls the phase shifter 11 to input two series of microwave signals 5llc and microwave signals 5 to the hybrid 20.
Since it operates so as to minimize the error ε from the correct phase difference of 90'' with 21c, it is included in the distortion signal Sout of the output of the distortion compensator of the present invention output from the output terminal t3 of the hybrid 20 on the output side. The component of the microwave signal input Sin that is generated is minimized, and the optimum phase adjustment is automatically performed, so there is no problem.

〔Effect of the invention〕

As explained above, in the distortion compensator of the present invention, the phase shifter is automatically optimally adjusted to minimize the input signal content in the output distortion signal. In addition to reducing costs, considering that this distortion compensator is used in the front stage of a high-power microwave power amplifier that inevitably has nonlinearity, it is possible to reduce the distortion compensator's internal distortion generator. Even if the amount of distortion changes due to changes in the level of the input signal, the content of unnecessary input signal components in the output signal is automatically kept to a minimum, which also facilitates the operation and maintenance of wireless equipment. .

[Brief explanation of the drawing]

FIG. 1 is a principle diagram showing the configuration of a microwave distortion compensator according to the present invention, FIG. 2 is a block diagram showing the configuration of a microwave distortion compensator according to an embodiment of the present invention, and FIG. 3 is a conventional microphone t, FIG. 2 is a block diagram of a seven-wave distortion compensator. In the figure, 20 is a hybrid, 11 is a phase shifter, 21 is a microwave amplifier, 22 is an attenuator, 30 is a control signal generator, 31 is a detector, and 32 is a controller.

Claims (1)

[Claims] An input-side hybrid (10) that inputs a microwave signal (Sin), branches it into two, and outputs the split signal;
0), two series of microwave signals (S1, S2
); a microwave amplifier (21) that amplifies the branched input signal (S2) and generates a distorted signal; The components of the input signal (Sin) are mutually canceled by inputting an attenuator (22) that adjusts the output level and two series of signals (S1, S2) in which the phase error ε has been corrected and the level has been adjusted.
In a distortion compensator consisting of an output-side hybrid (20) that outputs only the generated distortion signal from an output terminal (t3), an output terminal (for termination) of the output-side hybrid (20) is provided.
control signal C according to the signal level (Sc) appearing at t4).
The control signal generating section (30) generates a control signal C, and the control signal C generated by the control signal generating section (30) is transmitted to the phase shifter (1
1) and which the phase shifter (11) imparts to the microwave input signal (S1), the phase shift for phase error correction is applied to the output terminal (t) of the hybrid (20) on the output side.
4) A distortion compensator characterized in that the signal level appearing in (4) is applied so as to be maximized.