KR20000009734U - Multiple Linearization Circuit of Power Amplifier - Google Patents

Abstract

The present invention relates to a multiple linearization circuit of a power amplifier, and in the related art, the IMD attenuation generated between the elements of the IMD generator amplifier for the analog predistorter and the main amplifier element does not coincide with each other, thus limiting the IMD attenuation generated in the main amplifier. .

Therefore, the present invention generates pre-distortion means for pre-distorting a signal to be input to the main power amplifier by generating an artificial IMD component to primarily attenuate the IMD component generated in the main power amplifier, and the IMD component by the pre-distorted signal. And a feed forward linearization means for receiving the output of the primary attenuated main power amplifier and attenuating the IMD component secondarily.

Accordingly, the limit of linearity for the IMD attenuation of the analog predistorter linearization loop is improved, so that an improved IMD characteristic can be obtained.

Description

Multiple Linearization Circuit of Power Amplifier

The present invention relates to a multiple linearization circuit including a feed forward linearization circuit for improving an analog predistortor linearization circuit, and more particularly, to a multiple linearization circuit of a power amplifier adapted to be suitable for the linearization design of a high power amplifier. .

1 and 2 show a power amplifier linearization circuit using a conventional analog predistorter.

As shown, an analog predistorter 10 for artificially generating an IMD to attenuate intermodulation distortion (IMD) generated in the main amplifier (AMP), and predistorted RF. It consists of a driver amplifier 20 for amplifying a signal.

The main amplifier 30 includes first main amplifiers 31 and 32 and second main amplifiers 33, 34, 35, and 36 using TR in parallel to generate a high output, and decomposes an RF output. Hybrid coupler was used to synthesize.

2 shows a detailed view of the analog predistorter 10.

First, a MMIC amplifier (Q1) 11 for amplifying the RF input is provided, and TR (Q2) 12 is provided for artificially generating IMD in path 1, and DL1 for carrier removal in path 2 13 and COM1 14, and attenuator ATT3 15 and phase shifter PS3 16 for IMD level adjustment and phase adjustment are provided.

In addition, DL2 (17) and COM2 (18) for combining the IMD signal component synthesized with the path 1 and the path 2 and the carrier component of the path 3, and the MMIC amplifier (Q3) (19) for RF level amplification do.

The operation of the linearization circuit of the conventional power amplifier configured as described above is as follows.

In order to attenuate the IMD component generated in the main amplifier 30, an artificial IMD component is made in the analog predistorter 10, and the pre-distorted RF signal is passed through the driver amplifier 20 having a 34-35 dB gain. It is applied to the main amplifier 30 having an 18 dB gain so that the IMD component generated in the main amplifier 30 is minimized.

Looking at the detailed operation of the analog predistorter 10, the RF input signal level is Div1. Power is amplified at TR (Q1) 11 to compensate for the loss in Div2.

After an artificial IMD is generated by TR (Q2) 12 in path 1, the phase difference between the signal of path 2 and 180 ° is removed to remove the carrier component present in path 1.

After this signal is artificially adjusted by the level attenuator 15 and the phase shifter 16, it is synthesized with the path 3 signal to add a carrier and the IMD is in phase with the main amplifier 30. The phase difference between the IMD generated in and 180 ° is to be applied to the drive amplifier 20.

However, the above-described linearization circuit of the power amplifier has the following problems.

First, the IMD attenuation produced by the main amplifier is limited because the IMD characteristics generated between the elements of the analog predistorter IMD generator (Q2) and the main amplifier (D1, D2, D3, D4) do not match each other. There is a limit to linearization.

Second, due to the characteristic difference between the active elements in each path of the main amplifier, the generated IMD components are not the same. Therefore, an analog predistorter can attenuate the IMD with the best state of the main amplifier paths having different characteristics. There is no problem maximizing morphization.

Third, the devices must be selected because they all use the same characteristics of the device, there is a problem that the manufacturing cost increases, such as reduced productivity, increased defective rate.

Therefore, the present invention has been devised to solve the above-mentioned conventional problems, and an object of the present invention is that the IMD characteristics generated between the elements of the IMD generator amplifier for the analog predistorter and the main amplifier element do not coincide with each other. It is to provide a linearization circuit of a power amplifier that overcomes the limitation of attenuation.

A feature of the present invention for achieving the above object is a pre-distortion of a signal to be input to the main power amplifier by generating artificial IMD components to primarily attenuate the IMD components generated in the main power amplifier in the linearization circuit of the power amplifier. And a feed forward linearization means for receiving the output of the main power amplifier in which the IMD component is primarily attenuated by the predistorted signal, and for attenuating the IMD component secondarily.

It is still another object of the present invention to provide a linearization circuit of a power amplifier that overcomes the limitation of maximization of linearization due to the difference in characteristics of active elements in each path of the main amplifier due to the non-identical IMD component.

A feature of the present invention for achieving the above object is that the feedforward linearization means couples the RF input signal of the predistortion means and the output signal of which the IMD component is primarily attenuated in the main power amplifier, respectively, to form a carrier component. And a carrier canceling means for canceling and an IMD component damping means for amplifying a signal from which the carrier component is canceled through the carrier canceling means to attenuate the IMD component of the output of the main power amplifier.

1 is a block diagram of a linearization circuit of a power amplifier with a conventional analog predistorter,

2 is a detailed configuration diagram of a conventional analog predistorter;

3 is a block diagram of a multiple linearization circuit of a power amplifier according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: predistorter 20: driver amplifier

30: main amplifier 100: feed forward linearization unit

110: carrier attenuation portion 111: first coupling portion

112: first level attenuation control unit 113: first phase adjustment unit

114: first coupling portion 120: IMD attenuation portion

121: error amplifier 122: second level attenuation control unit

123: second phase adjusting unit 124: second coupling unit

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

3 shows a multiple linearization circuit of a power amplifier according to an embodiment of the present invention. As shown, an analog predistorter 10 for artificially generating the IMD to attenuate the IMD generated in the main amplifier, and a driver amplifier for amplifying the predistorted RF signal ( 20), the main amplifier 30, and the feed forward linearization unit 100 for receiving the output of the main power amplifier in which the IMD component is primarily attenuated by the predistorted signal and attenuating the IMD component secondarily. It is composed.

The feed forward linearization unit 100 couples the first coupling unit 111 coupling the RF input signal of the predistortion unit, and the output signal of which the IMD component is primarily attenuated in the main amplifier 30. The second coupling unit 115 to ring, and the first level adjusting unit 112 and the first phase adjusting unit 113 such that the first coupled signal has a 180 ° phase difference with respect to the second coupled signal. ), A first coupling unit 114 coupling the phase-controlled first coupled signal and the second coupling signal to cancel the carrier component, and an error of amplifying the output signal of the first coupling unit 114. A second level adjusting unit 122 and a second level adjusting unit 122 for adjusting the level and phase of the output signal of the error amplifier 121 to attenuate the IMD component of the output of the main amplifier 30 and the amplifier AError 121; A second phase controller 123 and an output of the second level controller 122 and the phase controller 123 to the output of the main amplifier 30. Combined is composed of a second engaging portion (124) for attenuating the IMD components secondarily.

In one embodiment, the carrier canceling unit 110 is configured to cancel a carrier component by coupling an RF input to a linearization circuit of a conventional power amplifier to have a phase difference of 180 ° with a signal coupled to the RF output. And an IMD attenuator 120 configured to amplify the IMD component signal to an appropriate level in the error amplifier 121 and synthesized with the main RF output path of the main amplifier 30 to maximize attenuation of the IMD component. Feedforward linearization circuitry is provided.

The operation of the multiple linearization circuit of the power amplifier according to the present invention configured as described above is as follows.

First, the IMD component generated by the main amplifier 30 is generated by the analog predistorter 10 so that the predistorted signal attenuates the IMD component of the main amplifier 30. In order to maximize the IMD component cancellation, the IMD generation component is significantly first-order due to the signal pre-distorted by the analog predistorter 10 after coupling the RF input to the first coupling unit 111. A first level attenuator ATT1 112 and a first phase adjuster are arranged so that the output of the attenuated main amplifier is 180 ° out of phase with the signal (2) coupled by the second coupling unit 115. Phase shifter (PS1) 113 is adjusted to cancel the RF carrier component at the first coupler 3.

After linearly amplifying the IMD component passed through the first combiner 114 in the error amplifier 121, the second level attenuation control unit ATT2 and 122 and the phase shifter PS2 123 are connected. Adjustment to maximize the attenuation of the IMD component synthesized in the second coupler 124.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common knowledge in the technical field to which the present invention pertains that various substitutions, conversions, and changes can be made without departing from the technical idea of the present invention. It will be apparent to those who have

According to the present invention it provides the following effects.

First, in the present multiple linearization circuit, the analog predistorter linearization loop shown in FIG. 1 is supplemented by using the linearization circuit of loop 2 to generate between the element of the IMD generation AMP (Q2) and the main amplifier element of the analog predistorter. Since the IMD characteristics do not coincide completely with each other, the improved IMD characteristics can be obtained by improving the linearity limitations that limit the IMD attenuation generated in the main amplifier.

Second, in the linearization circuit of loop 2, the IMD of the main amplifier output is used for linearization as it is, and the generated IMD components are not the same due to the characteristic difference between the active elements in each path of the main amplifier. The ability to attenuate the IMD to the same best state with all of the characteristic main amplifier paths solves the challenge of maximizing linearization.

Third, when the linearization circuit of only loop 2 is configured, in order to maximize the effect of IMD attenuation at the main amplifier output when the two loops are combined in the second combiner of FIG. 3, the amplification is caused by the nonlinearity of the error amplifier 212 of loop 2. There is a possibility that a problem of distorting a pure main amplifier IMD component may occur. However, this multiple linearization circuit first lowers the level of IMD that actually needs to be attenuated in loop 2 because the analog preamplifier first significantly reduces the level of the IMD component at the main amplifier output. Therefore, the level to be amplified in the error amplifier 121 of loop 2 also becomes small. As a result, nonlinearity of the error amplifier 121 of the loop 2 can be improved, and miniaturization and excellent linearity of the circuit of the loop 2 can be obtained.

Claims (4)

In the linearization circuit of a power amplifier, Predistortion means for generating artificial IMD components to primarily attenuate the IMD components generated in the main power amplifier and predistorting the signals to be input to the main power amplifier; And a feed forward linearization means for receiving the output of the main power amplifier in which the IMD component is firstly attenuated by the predistorted signal to attenuate the IMD component secondarily. . The method of claim 1, The feed forward linearization means comprises: carrier canceling means for coupling the RF input signal of the predistortion means and an output signal of which the IMD component is primarily attenuated in the main power amplifier to cancel the carrier component; And amplifying the IMD component of the main power amplifier output by amplifying the signal from which the carrier component is canceled through the carrier canceling means. The method of claim 2, wherein the carrier offset means, First coupling means for coupling the RF input signal of the predistortion means; Second coupling means for coupling an output signal of which an IMD component is primarily attenuated in the main power amplifier; Level and phase adjusting means for causing a first coupled signal to have a 180 [deg.] Phase difference with respect to said second coupled signal; And coupling means for combining the phase-controlled first coupled signal with the second coupled signal to cancel the carrier component. The method of claim 2, wherein the IMD component attenuation means, Amplifying means for amplifying the output signal of the carrier canceling means; Level and phase adjusting means for adjusting the level and phase of the output signal of the amplifying means to attenuate the IMD component of the main amplifier output; And a coupling means for coupling the output of the level and phase adjustment means to the output of the main amplifier to attenuate the IMD component secondarily.