JPH08316741A - Linearizer for non-monotonous phase distortion compensation - Google Patents

Abstract

PURPOSE: To compensate a phase characteristic of an amplifier changing non- monotonously with respect to an RF input level by adding a distortion generating route connecting an amplifier and a phase change device after a variable attenuator to a conventional linearizer and revising a fixed resistor attenuator before a linear amplifier into a variable attenuator. CONSTITUTION: Since amplifiers 3, 7, 10 all operates in the linear region when an RF input level is sufficiently low, the gain vectors of routes α, β in the linear and nonlinear amplifier route show prescribed values with respect to a change in the RF input level. On the other hand, as the RF level increases, since only the amplifier 7 operates in the linear region, the route α is decreased as the RF input level increases and the phase of the resultant vector C' is changed. When the RF input level is further increased, since the amplifier 10 operates also in the nonlinear region, the gain vectors of the routes α, β are both decreased and the phase of the resultant vector C" is further changed. Thus, a linearizer with a non-monotonous phase characteristic with respect to the RF input level change is realized.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a linearizer,
In particular, the present invention relates to a phase distortion compensation linearizer connected to an amplifier or the like whose phase changes non-monotonically with respect to a change in RF input level.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing the configuration of a conventional linearizer for phase distortion compensation, and FIGS. 4 (a) and 4 (b) are
It is a vector diagram which shows the gain vector in the prior art example, and its synthetic | combination vector.

As shown in FIG. 3, a conventional linearizer includes a demultiplexer 1 for demultiplexing an input RF signal into two, and a fixed resistance attenuator connected to one output end of the demultiplexer 1. Thirteen
And the phase changer 4 connected to the fixed resistance attenuator 13
An amplifier 3 connected to the phase changer 4, an amplifier 7 connected to the other output terminal of the demultiplexer 1, a variable attenuator 8 connected to the amplifier 7, and an output of the amplifier 3. It has a multiplexer 5 that combines the outputs of the variable attenuators 8. Here, the operations of the amplifier 3 and the amplifier 7 both have different linear regions with respect to the RF input level.

Next, the operation will be described. For the sake of explanation, the route formed by the phase changer 4 and the amplifier 3 in FIG. 3 is a linear amplification route, and the route formed by the amplifier 7 and the variable attenuator 8 is a non-linear amplification route. I will call it. In the region where the RF input level is low, both the amplifier 3 and the amplifier 7 operate in the linear region, so that the gain does not change with the change in the RF input level. Therefore, as shown in FIG. 4A, the gain vector [A] of the linear amplification route and the gain vector [B] of the non-linear amplification route show constant values with respect to changes in the RF input level. Therefore, the phase of the combined vector [C] corresponding to the output of the multiplexer 5 does not change.

On the other hand, in the region where the RF input level is high, only the amplifier 7 operates in the nonlinear region. Therefore, as the RF input level increases as shown in FIG. 4B, the gain vector [B 'of the nonlinear amplification route is obtained. ] Becomes smaller,
The phase of the composite vector [C '] changes. By being configured so that this phase change cancels the phase change of the amplifier or the like connected to the latter stage of the linearizer, the phase distortion of the amplifier or the like is compensated.

[0006]

A conventional linearizer may have a function of compensating for a phase change of an amplifier or the like having a monotonous phase change with respect to a change of an RF input level, but a non-monotonic phase change is caused. It was difficult to compensate the amplifier etc.

In view of the drawbacks of the prior art, it is an object of the present invention to provide a phase distortion compensator capable of excellent phase distortion compensation for an amplifier having a non-monotonic phase distortion characteristic with respect to a change in RF input level. To provide a linearizer.

[0008]

In order to solve the above problems, the linearizer for non-monotonic phase distortion compensation of the present invention is
A first demultiplexer for dividing an input RF signal into two waves, a first variable attenuator connected to one output end of the first demultiplexer, and an arbitrary variable attenuator for the first variable attenuator A first path including a first amplifier and a first phase changer connected in sequence,
A second demultiplexer connected to the other output terminal of the first demultiplexer, and a second amplifier connected to one output terminal of the second demultiplexer in any order. A second path including two variable attenuators, a first multiplexer that combines the output of the first path and the output of the second path, and the other of the second demultiplexer A third variable attenuator connected to the output end, a third path including a third amplifier and a second phase changer connected to the output of the third variable attenuator in any order, The second multiplexer combines the output of the first multiplexer and the output of the third path.

[0009]

According to the present invention, like the non-monotonic phase distortion compensating linearizer, the first variable attenuator connected to one output terminal of the first demultiplexer for dividing the input RF signal into two waves can be optionally used. A first path including a first amplifier and a first phase changer connected in this order, and one output of a second duplexer connected to the other output end of the first duplexer A second path including a second amplifier and a second variable attenuator connected to the end in any order, and a third variable attenuation connected to the other output end of the second demultiplexer A third amplifier connected to the output of the converter in any order and a third path including a second phase changer,
Each of the three amplifiers has a different linear region with respect to the RF input level, the output of the first path and the output of the second path are combined by the first combiner, and the first combiner is further combined. An output having a non-monotonic RF input level-phase characteristic can be obtained by synthesizing the output of the converter and the output of the third path by the second multiplexer.

[0010]

1 is a block diagram showing an embodiment of a linearizer for non-monotonic phase distortion compensation according to the present invention, FIG.
(C) is a vector diagram showing the gain vector and its combined vector, (d) is an output characteristic diagram showing the relationship between the input level and the phase change in the embodiment, and (e) is the non-monotonic phase distortion of the amplifier or the like to be compensated It is an output characteristic view which shows a characteristic.

In FIG. 1, 1 is a first demultiplexer for dividing an input RF signal into two waves, 2 is a variable attenuator connected to one output end of the demultiplexer 1, and 3 and 4 are respectively. An amplifier and a phase changer. Reference numeral 6 is a branching filter connected to the other output terminal of the branching filter 1, and reference numerals 7 and 8 are an amplifier and a variable attenuator connected to one output terminal of the branching filter 6. Reference numeral 5 is a multiplexer for combining the output of the phase changer 4 and the output of the variable attenuator 8. The variable attenuator 9, the amplifier 10 and the phase changer 11 are connected to the other output end of the demultiplexer 6, and 12 is the multiplexer 5
Is a multiplexer for synthesizing the output of 1 and the output of the phase changer 11. Here, the operations of the amplifier 3 and the amplifiers 7 and 10 have different linear regions with respect to the RF input level.

First, for the sake of explanation, the route constituted by the variable attenuator 2, the amplifier 3 and the phase changer 4 is a linear amplification route, and the route constituted by the amplifier 7 and the variable attenuator 8 is non-linear. The amplification route α and the route formed by the variable attenuator 9, the amplifier 10 and the phase changer 11 will be referred to as a non-linear amplification route β.

Next, the operation will be described. First, in the region where the RF input level is sufficiently low, all of the amplifier 3, the amplifier 7, and the amplifier 10 operate in the linear region, so that the gain vector [A] of the linear amplification route as shown in FIG. And the gain vector of the nonlinear amplification route α [B
₁ ] and the gain vector [B ₂ ] of the nonlinear amplification route β
Indicates a constant value with respect to changes in the RF input level. Therefore, the composite vector [C] corresponding to the output of the multiplexer 12
The phase of does not change.

However, as the RF input level rises, first, only the amplifier 7 operates in the non-linear region. Therefore, as shown in FIG. 2B, the non-linear amplification route α of the non-linear amplification route α increases. The gain vector becomes small as [B ₁ → B ₁ ′], and the combined vector [C ′]
The phase of changes.

When the RF input level is further increased, not only the amplifier 7 but also the amplifier 10 operates in the non-linear region. Therefore, as shown in FIG. 2C, as the RF input level rises, Both the gain vector [B ₁ → B ₁ ′] of the nonlinear amplification route α and the gain vector [B ₂ → B ₂ ′] of the nonlinear amplification route β become smaller, and the phase of the combined vector [C ″] further changes. An example of changes in input level-phase during operation is shown in FIG.

In the present embodiment, the input level-phase characteristics of the non-monotonic phase distortion compensating linearizer are the adjustment of the attenuation amount of each variable attenuator 2, 8 and 9, and each phase changer 4 and 11.
Can be easily changed arbitrarily by changing the phase shift according to (3) and changing the gain of each amplifier 3, 7, and 10.

As a result, a linearizer having a non-monotonic phase characteristic with respect to a change in the RF input level can be realized, and the obtained non-monotonic phase distortion compensating linearizer is:
The phase distortion of the amplifier or the like is compensated by connecting to the front stage of the amplifier or the like having a non-monotonic phase characteristic with respect to the RF input level change as shown in FIG.

[0018]

As described above, according to the present invention, a distortion generating route in which an amplifier and a phase changer are connected in any order after a variable attenuator is added to a conventional linearizer, and further linear operation is performed. By changing the fixed resistance attenuator located in front of the amplifier to a variable attenuator, excellent phase distortion compensation can be performed for an amplifier having a non-monotonic phase distortion characteristic with respect to a change in RF input level. .

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of a linearizer for non-monotonic phase distortion compensation.

FIG. 2 is a vector diagram showing a gain vector and its combined vector in the embodiments (a) to (c). (D) An output characteristic diagram showing the relationship between the input level and the phase change in the example.
(E) Output characteristic diagram showing non-monotonic phase distortion characteristics of the amplifier or the like to be compensated

FIG. 3 is a block diagram showing a configuration of a conventional linearizer for phase distortion compensation.

4A and 4B are vector diagrams showing a gain vector and a composite vector thereof in a conventional example.

[Explanation of symbols]

 1 demultiplexer 2 variable attenuator 3 amplifier 4 phase changer 5 multiplexer 6 demultiplexer 7 amplifier 8 variable attenuator 9 variable attenuator 10 amplifier 11 phase changer 12 multiplexer 13 fixed resistance attenuator

Claims (2)

[Claims] 1. A first demultiplexer for dividing an input RF signal into two waves, a first variable attenuator connected to one output terminal of the first demultiplexer, and the first demultiplexer. A first path including a first amplifier and a first phase changer connected in any order to the variable attenuator, and a second branch connected to the other output end of the first demultiplexer. A second path including a wave filter, a second amplifier and a second variable attenuator, which are connected to one output end of the second branching filter in any order, and A first multiplexer for combining an output and an output of the second path; a third variable attenuator connected to the other output end of the second demultiplexer; and a third variable attenuation A third path including a third amplifier and a second phase changer connected to the output of the multiplexer in any order, and the output of the first multiplexer and the output of the third path are combined. Second A linearizer for non-monotonic phase distortion compensation, which comprises a multiplexer. 2. A linearizer for non-monotonic phase distortion compensation, wherein each of the three amplifiers according to claim 1 has a linear region that operates differently with respect to an RF input level.