CN103401535A - Single-loop simulation predistorter of BUC (backup computer) module - Google Patents

Abstract

The invention relates to a single-loop simulation predistorter of a BUC (backup computer) module. The output end of the predistorter is connected with the input end of a power amplifier of the BUC module. The single-loop simulation predistorter comprises a first directional coupler, a second directional coupler, a first chain and a second chain, wherein the first chain and the second chain are connected with the first directional coupler and the second directional coupler, the first directional coupler is used for processing input signals and separating the input signals into a main signal and a coupling signal, the first chain is used for carrying out time delay processing on the main signal and comprises a time delay unit, the second chain is used for carrying out non-linear processing on the coupling signal to generate a non-linear distorted signal, the second chain comprises a non-linear generator, an attenuator and a phase shifter, the second directional coupler is used for outputting the signals, the non-linear distorted signal generated by the second chain is coupled to the main signal of the first chain to obtain the expected predistorted signal, the predistorted signal is outputted, and the non-linear generator adopts a field effect transistor made of gallium arsenide material. The predistorter has the advantages that the structure is simple, and the cost is lower.

Description

The single ring architecture analog predistortion device of a kind of BUC

Technical field

The present invention relates to a kind of analog predistortion device, relate in particular to the single ring architecture analog predistortion device of a kind of BUC.

Background technology

For a long time, for the efficiency of the power amplifier of communication system, develop skill and linearization technique is the focus of industry research.Power amplifier produces the nonlinear components such as third order intermodulation component, five rank intermodulation components, and wherein, the third order intermodulation component is topmost distorted signal, and five rank intermodulation components are less on the impact of power amplifier.If the third order intermodulation component can be offset as much as possible to identical or lower with other high order component amplitudes, so just can obtain predistortion effect preferably.

Known, the linearization technique of power amplifier can be divided into back-off technology, feedforward, feedback and predistortion etc.Traditional power amplifier generally adopts the back-off technology, by the method that reduces input power, improves the linearity of power amplifier.Although adopt the rollback technology to be simple and easy to realize, efficiency is low, cost is high and be only applicable to the linear not bery high system that requires.Adopt the power amplifier of feed-forward technique, although can greatly improve the linearity of power amplifier, its cost than high, difficulty large, the efficiency of power amplifier is lower.Adopt the power amplifier of feedback technique, simple, easily realize, but its frequency band is narrower, poor stability, and is only applicable to linear less demanding system.Pre-distortion technology is divided into analog predistortion and digital pre-distortion, and analog predistortion utilizes analog circuit to produce distorted signal in radio frequency domains; Digital pre-distortion refers to and on the numeric field basis of baseband signal, produces pre-distorted signals and be converted to radio frequency domains.

At present, the VSAT satellite system must possess the emissivities of certain linearity with the transmitter of BUC module as this system, its power amplifier when the transmission data.Therefore, the BUC module of VSAT system has following requirement to the non-linearization technology: 1) lower cost budgeting.Many microwave devices, owing to having concentrated most advanced now technology, have fabulous index, but simultaneously expensive, in the low cost of microwave band, realize more and more important in communication.2) the non-linear ability of good improvement, be mainly in succession after power amplifier, can effectively be suppressed in the situation of equal transmit power the amplitude of third order intermodulation product.3) good interference free performance and Electro Magnetic Compatibility.4) be suitable for batch production, conformity of production is good, easily debugging.

Therefore, those skilled in the art is devoted to develop a kind of analog predistortion device of single ring architecture with the BUC module for the VSAT satellite system.

Summary of the invention

Because the above-mentioned defect of prior art, technical problem to be solved by this invention is to provide a kind of single ring architecture analog predistortion device of BUC module.

For achieving the above object, the invention provides a kind of single ring architecture analog predistortion device of BUC module, the output of described analog predistortion device is connected with the input of the power amplifier of described BUC module, it is characterized in that, comprising: the first directional coupler, the second directional coupler and be connected the first link and second link of described the first directional coupler and the second directional coupler;

Described the first directional coupler is for the treatment of the input signal of described analog predistortion device: described input signal enters described the first directional coupler, and after entering described the first directional coupler, described input signal is divided into main signal and coupled signal;

Described the first link is for the treatment of described main signal; Wherein said the first link comprises delay unit;

Described the second link is for the treatment of described coupled signal, to produce the nonlinear distortion signal; Wherein said the second link comprises nonlinear generator, attenuator and phase shifter: described nonlinear generator is for producing described nonlinear distortion signal according to described coupled signal; The input of described attenuator is connected with the output of described nonlinear generator, be used to regulating the amplitude of described nonlinear distortion signal; The input of described phase shifter is connected with the output of described attenuator, be used to regulating the phase place of described nonlinear distortion signal;

Described the second directional coupler is used for output signal: described coupled signal produces after described the second link described nonlinear distortion signal is coupled to the described main signal through described the first link by described the second directional coupler, the pre-distorted signals that obtains expecting, and export described pre-distorted signals.

Further, the delay duration of the delay unit of described the first link is determined by the described nonlinear generator of described the second link, described attenuator and described phase shifter.

Further, described attenuator and described phase shifter are adjustable.

Further, described attenuator is regulated the amplitude of described nonlinear distortion signal according to the nonlinear component of the power amplifier generation of described BUC module, make the amplitude of described nonlinear distortion signal identical with the amplitude of described nonlinear component.

Further, described phase shifter is regulated the phase place of described nonlinear distortion signal according to described nonlinear component, the phase place that makes described nonlinear distortion signal and 180 ° of the phase phasic differences of described nonlinear component.

Further, described attenuator is electrically controlled attenuator, and described phase shifter is voltage controlled phase shifter.

Further, described nonlinear generator adopts the field-effect transistor of GaAs material.

In better embodiment of the present invention, provide a kind of monocycle analog predistortion device of BUC module.The output of predistorter of the present invention is connected with the input of BUC module, according to the third order intermodulation component of the main power amplifier of BUC module, simulates the pre-distorted signals of expectation, to offset the third order intermodulation component of BUC module master power amplifier.

Analog predistortion device of the present invention comprises the first directional coupler, the first link, the second link and the second directional coupler.The first directional coupler is for the treatment of input signal, and input signal, after the first directional coupler is processed, is divided into main signal and coupled signal.The first link is connected with the second link all with the first directional coupler.The first link is for the treatment of main signal, and it comprises delay unit, the time delay that delay unit causes mainly for each device that compensates in the second link.The second link, for the treatment of coupled signal, comprises nonlinear generator, attenuator and phase shifter.Nonlinear generator produces nonlinear distortion component, and coupled signal obtains the nonlinear distortion signal after nonlinear generator.Attenuator is for regulating the amplitude of nonlinear distortion signal, and phase shifter is used for the phase place of regulating the nonlinear distortion signal.Attenuator and phase shifter are all to regulate according to the third order intermodulation component of the main power amplifier of BUC module.The second directional coupler is connected with the second link with the first link respectively, for exporting the signal after processing, the nonlinear distortion signal of the second link is coupled in the first link through on the main signal of delay unit by the second directional coupler, with the pre-distorted signals that obtains expecting, and the pre-distorted signals of output expectation.

The monocycle analog predistortion device of BUC module of the present invention, structure is very simple, easily realizes, and adjustable parameter is relatively less; And for the not high VSAT system of linearity BUC module transmitter, analog predistortion device of the present invention has superiority on cost than rollback technology.

Below with reference to the technique effect of accompanying drawing to design of the present invention, concrete structure and generation, be described further, to understand fully purpose of the present invention, feature and effect.

The accompanying drawing explanation

Fig. 1 is the structure chart of the monocycle analog predistortion device of BUC module of the present invention;

Fig. 2 is the monocycle analog predistortion device of BUC module of the present invention and the connection layout of BUC module.

Embodiment

Below in conjunction with accompanying drawing, embodiments of the invention are elaborated: the present embodiment is implemented under with the technical solution of the present invention prerequisite, provided detailed execution mode and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

As shown in Figure 1, the single ring architecture analog predistortion device of BUC module of the present invention comprises: the first directional coupler, the second directional coupler and be connected the first directional coupler and the first link of the second directional coupler and the second link; The first link comprises delay unit; The second link comprises non-linear generator, attenuator and phase shifter.The first directional coupler is for the treatment of input signal: by the first directional coupler, input signal is divided into main signal and coupled signal, main signal is input signal, coupled signal is the signal that the first directional coupler is coupled out according to input signal, and wherein the phase difference of coupled signal and main signal is 90 °.

The first link is for the treatment of main signal, and delay unit is done delay process according to the time delay that the nonlinear generator in the second link, attenuator and phase shifter cause to main signal.

The second link is for the treatment of coupled signal.Nonlinear generator in the second link, attenuator and phase shifter are cascaded.Nonlinear generator produces nonlinear distortion component, and coupled signal obtains the nonlinear distortion signal after nonlinear generator.Attenuator is regulated the amplitude of nonlinear distortion signal according to the third order intermodulation component of the main power amplifier of BUC module.Phase shifter is regulated the phase place of nonlinear distortion signal according to the third order intermodulation component of the main power amplifier of BUC module, making the phase difference of phase place of the third order intermodulation component of the phase place of first linear distortion signal and main power amplifier is 180 °.

In a preferred embodiment of the present invention, attenuator adopts electrically controlled attenuator, and phase shifter adopts voltage controlled phase shifter, and because electrically controlled attenuator and voltage controlled phase shifter are all to adopt electric tune mode, they all need all to cross default control voltage and realize.Default control voltage difference, the amplitude of the third order intermodulation component of the main power amplifier of BUC module and phase place are also by difference, and this will directly affect the linear effects of last power amplifier.

The second directional coupler is connected with the second link with the first link.The nonlinear distortion signal coupling that the second directional coupler produces the second link is to the pre-distorted signals to obtain expecting on the main signal of processing through delay unit on the first link, and exports the pre-distorted signals of this expectation.

In a preferred embodiment of the present invention, the nonlinear generator of the monocycle analog predistortion device of BUC module of the present invention adopts the field-effect transistor of GaAs material.Use the field-effect transistor of GaAs material can produce the nonlinear distortion component that amplitude is larger, therefore the field-effect transistor that uses GaAs material can be applicable to as the predistorter of nonlinear generator the input signal that frequency is higher, and this is also more extensive as the scope of application of the predistorter of nonlinear generator than using diode.

In another preferred embodiment of the present invention, the monocycle analog predistortion device of BUC module of the present invention is applied to the BUC module of VSAT satellite system, and specifically as shown in Figure 2, the BUC module comprises Driver amplifier and main power amplifier.The output of analog predistortion device of the present invention is connected with the input of the Driver amplifier of BUC module, and the BUC module comprises Driver amplifier and and main power amplifier.Input signal P_InEnter monocycle analog predistortion device of the present invention: at first enter the first directional coupler, the first directional coupler is by input signal P_InBe divided into main signal and coupled signal; Then main signal enters the first link: through delay unit, make main signal have identical time delay with the nonlinear distortion signal that the second link produces, the while has also been improved the synchronism of the linearity of the main power amplifier output signal of BUC module; Coupled signal enters the second link: coupled signal is introduced into nonlinear generator, third order intermodulation component according to the main power amplifier of BUC module, nonlinear generator produces corresponding nonlinear distortion component, wherein the phase difference of the third order intermodulation component of the main power amplifier of nonlinear distortion component and BUC module is 90 °, and coupled signal obtains the nonlinear distortion signal after nonlinear generator; The nonlinear distortion signal enters attenuator, the amplitude of the nonlinear component that produces according to main power amplifier, and regulated attenuator, make the amplitude of nonlinear distortion signal equate with the amplitude of the third order intermodulation component of the main power amplifier of BUC module; The nonlinear distortion signal enters phase shifter, according to the phase place of the third order intermodulation component of the main power amplifier of BUC module, regulates phase shifter, makes 180 ° of the phase phasic differences of the phase place of nonlinear distortion signal and the third order intermodulation component that main power amplifier produces; Finally, the nonlinear distortion signal is coupled on main signal by the second directional coupler, the pre-distorted signals that obtains expecting, and export the pre-distorted signals of this expectation.After the pre-distorted signals of expectation enters the BUC module, offset the third order intermodulation component of main power amplifier in the BUC module, the signal P of the standby certain linearity of output device_out.

More than describe preferred embodiment of the present invention in detail.The ordinary skill that should be appreciated that this area just can design according to the present invention be made many modifications and variations without creative work.Therefore, all technical staff in the art, all should be in the determined protection range by claims under this invention's idea on the basis of existing technology by the available technical scheme of logical analysis, reasoning, or a limited experiment.

Claims (6)

1. the single ring architecture analog predistortion device of a BUC module, the output of described analog predistortion device is connected with the input of the power amplifier of described BUC module, it is characterized in that, comprising: the first directional coupler, the second directional coupler and be connected the first link and second link of described the first directional coupler and the second directional coupler;

Described the first directional coupler is for the treatment of the input signal of described analog predistortion device: after described input signal entered described the first directional coupler, described input signal was divided into main signal and coupled signal;

Described the first link is for the treatment of described main signal, and wherein said the first link comprises delay unit; Described the second link is for the treatment of described coupled signal, to produce the nonlinear distortion signal; Wherein said the second link comprises nonlinear generator, attenuator and phase shifter: described nonlinear generator produces described nonlinear distortion signal for the third order intermodulation component that the main power amplifier according to described coupled signal and described BUC module produces; The input of described attenuator is connected with the output of described nonlinear generator, be used to regulating the amplitude of described nonlinear distortion signal; The input of described phase shifter is connected with the output of described attenuator, be used to regulating the phase place of described nonlinear distortion signal;

Described the second directional coupler is used for output signal: described coupled signal produces after described the second link described nonlinear distortion signal is coupled to the described main signal through described the first link by described the second directional coupler, the pre-distorted signals that obtains expecting, and export described pre-distorted signals;

Described nonlinear generator adopts the field-effect transistor of GaAs material.

2. the single ring architecture analog predistortion device of a kind of BUC module as claimed in claim 1, wherein, the delay duration of the delay unit of described the first link is determined by the described nonlinear generator of described the second link, described attenuator and described phase shifter.

3. the single ring architecture analog predistortion device of a kind of BUC module as claimed in claim 1, wherein, described attenuator and described phase shifter are adjustable.

4. the single ring architecture analog predistortion device of a kind of BUC module as claimed in claim 3, wherein, described attenuator is regulated the amplitude of described nonlinear distortion signal according to the third order intermodulation component of the power amplifier generation of described BUC module, make the amplitude of described nonlinear distortion signal identical with the amplitude of described nonlinear component.

5. the single ring architecture analog predistortion device of a kind of BUC module as claimed in claim 3, wherein, described phase shifter is regulated the phase place of described nonlinear distortion signal according to described third order intermodulation component, the phase place that makes described nonlinear distortion signal and 180 ° of the phase phasic differences of described third order intermodulation component.

6. the single ring architecture analog predistortion device of a kind of BUC module as claimed in claim 3, wherein, described attenuator adopts electrically controlled attenuator, and described phase shifter adopts voltage controlled phase shifter.

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