KR20090071211A - Linearization apparatus for power amplifier of slave path in multi-path - Google Patents

Abstract

A linearization apparatus for a power amplifier of a slave path in a multi path is provided to reduce the loss of a signal and to simplify a circuit for linearization by compensating a non-linear characteristic of the output signal outputted from the power amplifier through a predistorter. A linearization apparatus includes a distributor(100) and a predistorter(200). The distributer distributes the signal outputted from the power combiner of the linearization apparatus installed in a master path. The predistorter receives the signal from the distributor and pre-distorts the fundamental frequency signal inputted to the power amplifier of the slave path. The distributor is installed between an error amplifier and the power combiner of the linearization apparatus. The predistorter includes a distortion error combiner. The distortion signal combiner outputs the predistortion signal by combining the signal inputted from the distributer and the fundamental frequency signal of the slave path.

Description

Linearization apparatus for power amplifier of slave path in multi-path}

The present invention relates to a linearization device for a power amplifier, and more particularly, to reduce the signal loss and simplify the circuit structure required for the linearization of a power amplifier to which a multiple input multiple output method is applied. The present invention relates to a power amplifier linearization device.

In recent years, the wireless communication field has been concentrated on personalization and multimedia, and ultimately, technology development has been made toward the next generation communication technology of 3.5G and 4G beyond IMT-2000. In order to be widely used for wireless communication, stable operating system, high performance communication base station system, and miniaturization, light weight, and low price should be achieved, and research and source technology of RF core components such as power amplifier are essential for enhancing stability and competitiveness.

What is important in the digital system is that data must be transmitted only by maintaining the linearity of the signal with linear modulation. The high power amplifier is responsible for maintaining the linearity of these signals and transmitting them. In general, it is common to have nonlinear circuit characteristics by the nonlinear characteristics of active elements used in RF and microwave circuits.

In particular, the power amplifier operates the transistor, which is the main active element, in a saturation region with strong nonlinear characteristics to extract the maximum power, and intermodulation signals are generated due to the nonlinear characteristics near the saturation region.

The intermodulation signals as described above act as interference or noise, causing deterioration of transmission quality. Therefore, when used with a power amplifier by incorporating a linearization technology that compensates for the non-linear characteristics of the power amplifier, it is possible to obtain a desired output power while significantly reducing intermodulation signals generated during co-amplification of multiple carriers even in a saturated region.

Such linearization methods include a back-off method, a negative feedback method, a predistortion method, and a feedforward method.

In the linearization method using predistortion, the predistortion circuit having inverse distortion characteristics is installed in the input stage of the power amplifier in consideration of the distortion component generated when the basic input signal is amplified by the main amplifier. This is a method of canceling the distortion component.

In addition, the linearization method through the feedforward extracts some of the output signal and then removes the coupling signal from the original input signal, thereby leaving only the inverse intermodulation (IMD) signal, and the negative intermodulation signal is an error amplifier ( After amplification through the error amplifier, the main amplifier's output terminal is recombined with the main signal to cancel the distortion component of the main amplifier.

Therefore, the conventional power amplifier adopts the above-described predistortion type or feed forward type linearization device, thereby compensating for the nonlinear characteristics of the power amplifier, thereby ensuring linearity.

However, the conventional power amplifier employing the linearization device does not have a big problem when used in a single input single output mobile communication system, but moves 3.5 generations like WiBro (Wireless Broadband Internet). When applied to a communication system, a number of problems are caused in terms of signal loss and production cost due to the multiple input multiple output (MIMO) method.

In more detail, when the above-described conventional power amplifier is installed in a multi-input multiple output type repeater, the power amplifier should be installed in both the multipath consisting of the master path and the slave path. In this case, since the power amplifier adopts all the linearizers, the circuit structure becomes complicated and the production cost of the power amplifier is greatly increased.

In addition, since a delay element such as a delay is used as the linearizer of the power amplifier, a loss of an output signal is inevitably generated, which causes a problem of lowering the overall performance of the device employing the power amplifier.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to simplify the linearization apparatus of a power amplifier installed in a slave path of a multipath. To provide a linearizer.

It is another object of the present invention to provide a power amplifier linearization apparatus of a slave path among multiple paths that can reduce the loss of an output signal during the linearization of the power amplifier.

The above object of the present invention is to linearize the output signals of the power amplifiers respectively installed in the master path and the slave path according to the multiple input multiple output method, and distribute the signals output from the power combiner of the linearization device installed in the master path. A distributor; A pre-distorter for predistorting a source frequency signal inputted to a power amplifier of a slave path by receiving a signal from the splitter may be achieved through a power amplifier linearizer of a slave path among multiple paths.

Therefore, the present invention compensates the nonlinear characteristics of the output signal output from the power amplifier of the slave path through the divider of the master path and the predistorter of the slave path, thereby simplifying the circuit structure, reducing the volume, and greatly increasing the cost of the linear power amplifier. There is a very useful effect that can be reduced.

In addition, in the present invention, since a delay element such as a delay is not used in the linearization process, the loss of the output signal due to signal delay is minimized, thereby improving the performance of equipment such as a repeater employing a linear power amplifier.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<First Embodiment>

FIG. 1 is a circuit diagram schematically illustrating a power amplifier linearization device of the present invention in which a master path and a slave path are configured one by one. As shown, the present invention is composed of a divider 100 and a predistorter 200.

First, the divider 100 distributes a signal coupled from an output signal of the power amplifier PA ₀ installed in the master path TX _{0. In the} present invention, as an example, the linearity of the power amplifier PA ₀ is secured. The above-described distributor 100 was installed at the output of the power combiner 13 of the linearizer 10 installed for the purpose.

Accordingly, the divider 100 outputs an interphase intermodulation signal input from the power combiner 13 to the error amplifier 14 and the predistorter 200 described above.

Here, the feed forward linearization device 10 including the couplers 11 and 12, the power combiner 13, the error amplifier, and the delay 15 and 16 is installed in the master path TX ₀ . By compensating for the nonlinear characteristics of the power amplifier PA ₀ installed in the master path TX ₀ . However, in addition to the feedforward linearization device 10, various linearization devices such as a back-off method, a negative feedback method, and a predistortion method may be applied.

The predistorter 200 receives an antiphase intermodulation signal from the divider 100 and predistorts a fundamental frequency signal inputted to the power amplifier PA ₁ of the slave path TX ₁ . In the present invention, as an example, the distortion signal combiner can predistort a fundamental frequency signal of the slave path TX ₁ .

Therefore, the power amplifier PA ₁ installed in the slave path TX ₁ is input with the predistorted signal from the predistorter 200 in addition to the source frequency, that is, an interphase intermodulation signal. _The signal output from ₁ ) can ensure linearity.

Thus, the present invention is a master path (TX _0), a divider 100, a slave path (TX ₁₎ power amplifier installed in the slave path (TX ₁₎ pre through distorter 200 is installed in (PA installed in compensating for non-linear _{characteristics: 1)} it can be very simply implement the linearization of the power amplifier group (PA ₁₎ provided in the slave path (TX _1).

In particular, the predistorter 200 of the present invention simply consists of a distortion signal combiner, which greatly simplifies the circuit configuration, thereby not only significantly reducing the cost of the linear power amplifier, but also greatly reducing the volume. .

In addition, in the predistorter 200 of the present invention, since a delay element such as delays 15 and 16 is not used in the slave path TX ₁ , the loss of the output signal due to signal delay can be minimized. The performance of equipment such as a repeater employing a power amplifier can be improved.

Second Embodiment

FIG. 2 is a circuit diagram schematically illustrating another example of a multipath consisting of one master path and a plurality of slave paths and a linearization device of a power amplifier according to another embodiment of the present invention.

As shown, each pre-distorter 200 is installed in each slave path TX ₁ to TX _n , and the predistorter 200 transposes source frequency signals of the slave paths TX ₁ to TX _n . The distortion compensates for the nonlinear characteristics of the power amplifiers PA ₁ to PA _n installed in the respective slave paths TX ₁ to TX _n .

Thus the present invention shown in Figure 2 is the master path (TX ₀₎ only in the feed forward or predistortion, and linearization device 10 is installed, such as, the master path remaining multipath that is, a plurality of the slave path, except for (TX ₀₎ ( TX ₁ ~ TX _n ) is because the predistorter 200 is installed respectively, greatly reducing the circuit structure and volume for the linearization as a whole, and dramatically reduces the cost of the linear power amplifier.

Third Embodiment

FIG. 3 shows another embodiment of the present invention, and is a circuit diagram schematically illustrating an example of a multipath including a plurality of master paths and slave paths and a linearization device of a power amplifier.

As shown, all the distributors 100 are installed in each of the master paths TX ₀ and TX2 ₂ in which the linearizer 10 is installed, and the predistorter 200 is installed in each of the slave paths TX ₁ and TX ₃ . Are all installed.

Therefore, each predistorter 200 receives a signal from each of the distributors 100 installed in the master paths TX ₀ and TX2 ₂ and presistors the source frequency signals of the slave paths TX ₁ and TX ₃ . The nonlinear characteristics of the power amplifiers PA _{1 and} PA ₃ installed in the paths TX ₁ and TX ₃ are compensated for.

Accordingly, in the present invention shown in FIG. 3, the linearizer 10 such as feedforward or predistortion is installed only in the master paths TX ₀ and TX ₂ , as in the first embodiment, and the remaining multipaths, that is, multiple slave paths. Since the predistorters 200 are respectively installed in the TX ₁ and TX ₃ , the circuit structure and volume for linearization are greatly reduced, and the cost of the linear power amplifier is greatly reduced.

As described above, the embodiments of the present invention are merely illustrative of preferred examples, and the scope of application of the present invention is not limited thereto, and may be appropriately changed within the scope of the same idea.

1 is a circuit diagram schematically showing a linearization device for a power amplifier of the present invention.

2 is a circuit diagram schematically showing another embodiment of the linearizer for power amplifier of the present invention.

Figure 3 is a circuit diagram schematically showing another embodiment of the linearizer for power amplifier of the present invention.

<Description of Symbols for Main Parts of Drawings>

10: linearization device 100: distributor

200: Predistorter TX ₀ , TX ₁ , TX ₂ , TX ₃ , TX _n : Path

PA ₀ , PA ₁ , PA ₂ , PA ₃ , PA _n : power amplifier

Claims (6)

In linearizing the output signals of the power amplifiers respectively installed in the master path and the slave path according to the multiple input multiple output method, A divider for distributing a signal output from a power combiner of the linearizer installed in the master path; Predistorter for receiving the signal from the divider and predistorting the source frequency signal input to the power amplifier of the slave path. Power amplifier linearizer of the slave path of the multi-path, characterized in that comprises a. The apparatus of claim 1, wherein the linearizer of the master path is any one of a backoff method, a negative feedback method, a predistortion method, and a feedforward method. The apparatus of claim 1, wherein the master path is composed of one path, and the slave path is composed of a plurality of paths. The apparatus of claim 1, wherein the master path and the slave paths each include a plurality of master paths. 2. The linearizer of claim 1, wherein the divider is installed between the power combiner and the error amplifier of the linearizer. The power amplifier of claim 1, wherein the predistorter comprises a distortion signal combiner for outputting a predistortion signal by combining a signal input from the distributor and a source frequency signal of the slave path. Linearizer.

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