CN202931370U - Radio frequency predistortion circuit - Google Patents
Radio frequency predistortion circuit Download PDFInfo
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- CN202931370U CN202931370U CN2012205718081U CN201220571808U CN202931370U CN 202931370 U CN202931370 U CN 202931370U CN 2012205718081 U CN2012205718081 U CN 2012205718081U CN 201220571808 U CN201220571808 U CN 201220571808U CN 202931370 U CN202931370 U CN 202931370U
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- phase shifter
- variable phase
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- radio frequency
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Abstract
The utility model provides a radio frequency predistortion circuit, including a variable phase shifter, a compensation amplifier, and a variable gain circuit. The variable phase shifter receives an input signal and is controlled by the power size of the input signal and the control voltage of the variable phase shifter. The compensation amplifier is connected with the variable phase shifter, and carries out attenuation compensation on the signal outputted by the variable phase shifter. The variable gain circuit is connected with the compensation amplifier, and carries out amplitude-amplitude conversion and amplitude-phase conversion on the compensated signal. According to the utility model, the variable phase shifter and the compensation amplifier are added in front of the traditional radio frequency predistortion circuit, the variable phase shifter only has the AM-PM characteristic, the AM-AM is constant, and the compensation amplifier after the variable phase shifter compensates the gain loss of the variable phase shifter. In this way, the variable phase shifter and the compensation amplifier and a follow-up variable gain circuit form the predistortion circuit which has independently controlled gain and phase, so that the linearity of the follow-up radio frequency power amplifier can be improved.
Description
Technical field
The utility model relates to the technology for radio frequency field, and specifically, the utility model relates to a kind of radio frequency distortion circuit.
Background technology
In order to improve the availability of frequency spectrum, extensively adopted linear modulation mode and the multi-transceiver technology of non-permanent envelope in modern wireless communication systems, this linearity to radio-frequency power amplifier has proposed very high requirement.And in order to improve power efficiency, generally allowing radio-frequency power amplifier be operated near saturation point, it is very serious that this non-linear hour becomes.Solve the contradiction between power efficiency and spectrum efficiency, linearization technique is very crucial.The linearization technique research of power amplifier can be traced back to eighties of last century the '20s.Nineteen twenty-eight in the American Harold.S.Black of Bell Laboratory work has invented feedforward and negative-feedback technology and has been applied to Amplifier Design, has reduced amplifier distortion effectively, can think the beginning of power amplifier linearization technical research.To the seventies and eighties in last century, the linearization technique of radio-frequency power amplifier obtains develop rapidly.By contrast, domestic also this technical research is not caused enough attention, only has minority unit to carry out the research work of this respect.From the paper of delivering, the overwhelming majority belongs to introductory article, and the academic research paper is less.
The radio frequency distortion technology is one of a kind of effective power amplifier linearization technology, and its advantage is not existence and stability problem, and wider signal band is arranged, and can process multi-carrier signal.And the pre-distortion technology circuit structure is comparatively simple, the lower and moderate performance of cost.Therefore the predistortion linear technology is more widely used than other several technology.
The key of radio frequency distortion technology is the characteristic that obtains the transmission of predistortion device, then designs and Implements with side circuit.At present the most frequently used is also that fairly simple analog predistortion network is the third order intermodulation component of eliminating power amplifier, is called three rank analog predistortion devices.For a communication system, the third order intermodulation component is main distorted signal, equates as five rank intermodulations with adjacent high-order component or lower slightly if the third order intermodulation component is eliminated, and just can obtain linearisation effect preferably.
Summary of the invention
Technical problem to be solved in the utility model is to provide a kind of radio frequency distortion circuit, can improve the linearity of follow up amplifier.
For solving the problems of the technologies described above, the utility model provides a kind of radio frequency distortion circuit, comprising:
Variable phase shifter receives an input signal and is subjected to the watt level of described input signal and the control voltage control of described variable phase shifter;
Compensated amplifier is connected with described variable phase shifter, to making attenuation compensation from the signal of described variable phase shifter output; And
Variable gain circuit is connected with described compensated amplifier, and the described signal after compensation is completed the conversion of amplitude～amplitude and the conversion of amplitude～phase place.
Compared with prior art, the utlity model has following advantage:
The utility model increases a variable phase shifter and a compensated amplifier by the front in the conventional radio frequency predistortion circuit, variable phase shifter only has AM～PM characteristic, AM～AM is constant, and compensated amplifier following closely compensates the gain loss of this variable phase shifter.Like this, they are combined with the variable gain circuit of further part and can form the predistortion circuit that a gain and phase place are independently controlled, thereby can improve the linearity of follow-up radio-frequency power amplifier.
Description of drawings
The above and other feature of the present utility model, character and advantage will become more obvious by the description below in conjunction with drawings and Examples, wherein:
Fig. 1 is the structure chart of the radio frequency distortion circuit of an embodiment of the utility model.
Embodiment
The utility model is described in further detail below in conjunction with specific embodiments and the drawings; set forth in the following description more details so that fully understand the utility model; but the utility model obviously can be implemented with the multiple alternate manner that is different from this description; those skilled in the art can be in the situation that do similar popularization, deduction without prejudice to the utility model intension according to practical situations, therefore should be with the content constraints of this specific embodiment protection range of the present utility model.
Fig. 1 is the structure chart of the radio frequency distortion circuit of an embodiment of the utility model.As shown in Figure 1, this radio frequency distortion circuit 100 mainly comprises variable phase shifter 101, compensated amplifier 102 and variable gain circuit 103.Wherein, variable phase shifter 101 receives an input signal and is subjected to the watt level of input signal and the control voltage control of variable phase shifter 101.Compensated amplifier 102 is connected with variable phase shifter 101, to making attenuation compensation from the signal of variable phase shifter 101 outputs.Variable gain circuit 103 is connected with compensated amplifier 102, and the signal after compensation is completed the (conversion of AM～AM) and the amplitude～phase place (conversion of AM～PM) of amplitude～amplitude.
And traditional predistortion circuit generally only adopts the last part in Fig. 1, namely only has variable gain circuit 103, and its shortcoming is that AM～AM and AM～PM characteristic are to bundle, in case definite, AM～PM characteristic just necessarily is determined when AM～AM characteristic.When the AM of predistortion circuit～AM characteristic satisfies the AM of radio-frequency power amplifier～AM characteristic, the AM of the predistortion circuit～PM characteristic AM that satisfies surely radio-frequency power amplifier～PM characteristic that just differs, thus cause the linearity not good.
Therefore, the utility model increases a variable phase shifter and a compensated amplifier by the front in the conventional radio frequency predistortion circuit, variable phase shifter only has AM～PM characteristic, and AM～AM is constant, and compensated amplifier following closely compensates the gain loss of this variable phase shifter.Like this, they are combined with the variable gain circuit of further part and can form the predistortion circuit that a gain and phase place are independently controlled, thereby can improve the linearity of follow-up radio-frequency power amplifier.
Although the utility model with preferred embodiment openly as above, it is not to limit the utility model, and any those skilled in the art can make possible change and modification within not breaking away from spirit and scope of the present utility model.Therefore, every content that does not break away from technical solutions of the utility model, according to technical spirit of the present utility model to any modification, equivalent variations and modification that above embodiment does, within all falling into the protection range that the utility model claim defines.
Claims (1)
1. a radio frequency distortion circuit (100), is characterized in that, comprising:
Variable phase shifter (101) receives an input signal and is subjected to the watt level of described input signal and the control voltage control of described variable phase shifter (101);
Compensated amplifier (102) is connected with described variable phase shifter (101), to making attenuation compensation from the signal of described variable phase shifter (101) output; And
Variable gain circuit (103) is connected with described compensated amplifier (102), and the described signal after compensation is completed the conversion of amplitude～amplitude and the conversion of amplitude～phase place.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012205718081U CN202931370U (en) | 2012-11-01 | 2012-11-01 | Radio frequency predistortion circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012205718081U CN202931370U (en) | 2012-11-01 | 2012-11-01 | Radio frequency predistortion circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202931370U true CN202931370U (en) | 2013-05-08 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012205718081U Expired - Fee Related CN202931370U (en) | 2012-11-01 | 2012-11-01 | Radio frequency predistortion circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN202931370U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111355503A (en) * | 2018-12-21 | 2020-06-30 | 瑞昱半导体股份有限公司 | Compensating device for amplitude modulation and phase modulation distortion |
| US11990875B2 (en) | 2019-01-10 | 2024-05-21 | Telefonaktiebolaget Lm Ericsson (Publ) | Bias circuit and power amplifier circuit |
-
2012
- 2012-11-01 CN CN2012205718081U patent/CN202931370U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111355503A (en) * | 2018-12-21 | 2020-06-30 | 瑞昱半导体股份有限公司 | Compensating device for amplitude modulation and phase modulation distortion |
| US11990875B2 (en) | 2019-01-10 | 2024-05-21 | Telefonaktiebolaget Lm Ericsson (Publ) | Bias circuit and power amplifier circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130508 Termination date: 20161101 |
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| CF01 | Termination of patent right due to non-payment of annual fee |