JPH03159407A - Non-linear compensation circuit for high frequency amplifier - Google Patents

Abstract

PURPOSE:To adjust the quantity of distortion without using a variable attenuator by adjusting the quantity of distortion which occurs in an amplifier for distortion occurrence by means of varying and adjusting the drain voltage of the amplifier concerned. CONSTITUTION:An input signal inputted to an input terminal 1 is distributed into three in a distributor 12 and a first distributed output is guided to the amplifier for distortion occurrence 20. A second distributed output is guided to a linear amplifier 21, is amplified without including a distortion component, is guided to a synthesizer for distortion extraction 30 and is synthesized with an output including the distortion component of the amplifier for distortion occurrence 20 in an opposite phase. Thus, only the distortion component is extracted and the output is guided to a synthesizer 31. A third distributed output is amplified in a linear amplifier 22 without including the distortion component, is guided to the synthesizer 31, is synthesized with an output passing through the variable attenuator 25d of the synthesizer for distortion extraction 30 in the opposite phase. The synthesized output is inputted to an amplifier 40 which is to compensate, the distortion component which occurs in the amplifier 40 is cancelled and the output is amplified and outputted to an output terminal 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a nonlinear compensation circuit that corrects signal distortion caused by nonlinearity of a high frequency amplifier.

[Conventional technology]

FIG. 5 shows a conventional nonlinear compensation circuit for a high frequency amplifier disclosed in, for example, Japanese Unexamined Patent Publication No. 52-5240. In the figure, 1 is an input terminal, 2 is an output terminal, and l2 is an input signal terminal. A divider that divides into three parts, 2.0 is a distortion generation amplifier, 21 and 22 are linear amplifiers, 25a to 25e are variable attenuators, and 30 is a composite of the outputs of the distortion generation amplifier 20 and the linear amplifier 21 in opposite phase. and a distortion extraction combiner for extracting distortion; 31 is a combiner for combining the distortion components extracted by the distortion extraction combiner 30 and the output of the linear amplifier 22 in opposite phase;
40 is a high frequency amplifier to be compensated.

Next, the operation will be explained.

The input signal input to input terminal 1 is divided into three parts by distributor 12. The first distribution output of the distributor 12 is a variable attenuator 25a.
After being attenuated to a predetermined power by
0 is introduced. The variable attenuator 25a is used to adjust the amount of distortion generated by the distortion generation amplifier 20. The signal amplified by the distortion generation amplifier 20 is derived including distortion, and is passed through the variable attenuator 25b for distortion extraction. It is introduced into the combiner 30. The second distribution output of the distributor 12 is introduced into the linear amplifier 21 through the variable attenuator 25c,
The signal is amplified without including any distortion components, and then introduced into the distortion extraction amplification device 30. In the distortion extracting signal generator 30, the distortion generating amplifier 20
By combining the output containing the distortion component and the output not including the distortion component of the linear amplifier 21 in opposite phase, only the distortion component of the output of the distortion generating amplifier 20 is extracted, and the output is combined. Introduced in Kaikiki 31. The third distribution output of the distributor 12 is amplified by the linear amplifier 22 through the variable attenuator 258 without including any distortion component, and then introduced into the amplifier 31. In the combiner 31, the output of the distortion extraction combiner 30 through the variable attenuator 25d and the output of the linear amplifier 22 are combined in opposite phase, and the combined output is input to the amplifier 40 to be compensated. The signal is amplified by canceling the distortion generated by the amplifier 40, and is output to the output terminal 2. Here, the variable attenuator 25d is adjusted so as to cancel out the distortion component generated by the amplifier 40 and so that no distortion component is output to the output terminal 2.

[Problem to be solved by the invention]

Since the nonlinear compensation circuit of conventional high-frequency amplifiers is structured as described above, a variable attenuator was required on the input side of the distortion generating amplifier in order to adjust the amount of distortion generated by the distortion generating amplifier. . Furthermore, this has led to problems such as an increase in the size of the circuit.

This invention was made to solve the above-mentioned problems, and its purpose is to provide a nonlinear compensation circuit for a high-frequency amplifier that can adjust the amount of distortion generated in a distortion-generating amplifier without using a variable attenuator. shall be.

[Means to solve the problem]

The nonlinear compensation circuit for a high frequency amplifier according to the present invention is one in which the drain voltage or collector voltage of the distortion generating amplifier is made variable.

[Effect]

The nonlinear compensation circuit for a high frequency amplifier according to the present invention adjusts the amount of distortion generated in the distortion generating amplifier by using the drain voltage or collector voltage of the distortion generating amplifier.

〔Example〕

An embodiment of the present invention will be described below.

In FIG. 1, 1 is an input terminal, 2 is an output terminal, 12 is a distributor that divides the input signal into three parts, 20 is a distortion generation amplifier,
21 and 22 are linear amplifiers, 25b to 256 are variable attenuators, and 30 is the distortion generation amplifier 20 and the linear amplifier 2.
A distortion extracting combiner 31 combines the outputs of the distortion extracting combiner 30 and the output of the linear amplifier 22 in reverse phase to extract distortion. Goal to go together, 4
0 is a high frequency amplifier to be compensated, 50 is a drain bias application terminal of the distortion generation amplifier, and 51 is a variable voltage power supply connected to the drain bias application terminal 50 of the distortion generation amplifier. The input signal input to the input terminal l is divided into three by the distributor 12. The first distribution output of the divider 12 is connected to the distortion generation amplifier 2.
Introduced in 0. Drain terminal 5 of distortion generation amplifier 20
The drain voltage Vd applied to 0 is a variable voltage voltage B51.
It is variable. Figure 2 shows a distortion generation amplifier 20.
This is an input/output characteristic using the drain voltage Vd as a parameter, and it can be seen that even if the input power Pia is the same, when the drain voltage Vd is decreased, the output power P out decreases, resulting in a more nonlinear operation. Since distortion is caused by nonlinear operation, it is possible to adjust the amount of distortion generated by the distortion generation amplifier 20 by Vd. Therefore, here, the drain voltage Vd applied to the drain bias application terminal 50 is controlled by the variable voltage power supply 51 to adjust the amount of distortion generated in the distortion generation amplifier.

The signal amplified by the distortion generation amplifier 20 is derived including a distortion component, and is introduced into the distortion extraction synthesizer 30 through the variable attenuator 25b. The second distributed output of the divider l2 is introduced into the linear amplifier 2l through the variable attenuator 25c,
The signal is amplified without including any distortion components, and then introduced into the distortion extraction amplification device 30. In the distortion extractor 3o, the distortion generation amplifier 20
By combining the output containing the distortion component and the output not including the distortion component of the linear amplifier 21 in reverse phase, only the distortion component of the output of the distortion generating amplifier 20 is extracted, and the output is combined. It is introduced into the container 31. The third distribution output of the distributor 12 is amplified by the linear amplifier 22 without including any distortion components through the variable attenuator 25e, and then introduced into the combiner 3l. In the combiner 31, the output of the distortion extraction combiner 30 through the variable attenuator 25d and the output of the linear amplifier 22 are combined in opposite phase, and the combined output is input to the amplifier 40 to be compensated. The signal is amplified by canceling out the distortion components generated at 40, and is output to the output terminal 2. Here, the variable attenuator 25d is adjusted so as to cancel out the distortion component generated by the amplifier 40 and so that the distortion component is not outputted to the output terminal 2.

In the above embodiment, only the drain voltage of the distortion generating amplifier 20 is made variable, but the drain voltage of the linear amplifier 2l22 may also be made variable. A second embodiment of the invention thus constructed is shown in FIG.

In FIG. 1, when the passing phase of the distortion generating amplifier 20 changes depending on the drain voltage, when the signals are combined by the distortion extracting combiner 30 and the valley combiner 31, the phase deviates from the inverse sum. is possible. However, by making the drain voltages of the distortion generation amplifier 20 and the linear amplifiers 21.22 equal as shown in FIG. 3, the passing phase relationship between the distortion generation amplifier 20 and the linear amplifiers 21.22 is constant regardless of the drain voltage. is maintained, and the phase of the combined signals is maintained in opposite phase in the distortion extraction combiner 30 and combiner 31. In addition, in the above embodiment, one distortion generation amplifier and two Although a circuit configuration including two linear amplifiers has been described, similar effects can be obtained in other circuit configurations.

FIG. 4 shows a third embodiment of the present invention. In FIG. 4, 10a is a divider that divides the signal input to the input terminal l into two parts, and 10b is a distortion extractor for the signal amplified by the linear amplifier 21. This is a distributor that distributes into two parts, a container 30 and a combiner 3l.

In this case, by changing the drain voltages of one distortion generation amplifier 20 and one linear amplifier 2l,
The same effect as the embodiment shown in the figure is achieved.

〔Effect of the invention〕

As described above, according to the present invention, the amount of distortion generated in the distortion generating amplifier is adjusted by varying the drain voltage of the amplifier, so the amount of distortion is adjusted using the variable attenuator. This has the effect of making the circuit smaller. ，

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a nonlinear compensation circuit for a high-frequency amplifier according to an embodiment of the present invention, FIG. 2 is a human output characteristic diagram of the distortion generating amplifier used in the above embodiment, and FIGS. FIG. 5 is a diagram showing the configuration of a conventional nonlinear compensation circuit for a high frequency amplifier according to another embodiment of the present invention. 1 is an input terminal, 2 is an output terminal, 12 is a 3-way divider, 20 is an amplifier for distortion generation, 21.22 is a linear amplifier, 30 is a combiner for distortion extraction, 31 is a combiner, 40 is a compensation device A high frequency amplifier, 50 is a drain bias application terminal, and 51 is a voltage variable power source.

Claims (1)

[Claims] (1) In a circuit that includes a distortion generation amplifier and uses distortion components generated by the amplifier to compensate for the nonlinear characteristics of a high frequency amplifier, a means for varying the drain voltage or collector voltage of the distortion generation amplifier is provided. A nonlinear compensation circuit for high frequency amplifiers featuring: