CN101110595A - Multilevel linc transmitter - Google Patents

Abstract

The invention relates to a multilevel LINC transmitter. The multilevel LINC transmitter comprises a multilevel signal component separator, a phase modulator block, and an RF block. The multilevel signal component separator comprises a multilevel scaler and converts a base band signal to constant envelope signals. The phase modulator block is coupled to the multilevel signal component separator. The RF block comprises a plurality of power amplifiers coupled to the phase modulator block and the multilevel scaler and a power combiner coupled to the power amplifiers.

Description

Multistage LINC reflector

Technical field

The present invention is particularly to a kind of multistage LINC reflector relevant for the linear amplification with non-linear component (Linear amplification withnonlinear components is hereinafter to be referred as LINC) reflector.

Background technology

In order to prolong the battery useful life of mobile hand-held device, in the wireless mobile communication system to the efficiency of electricity usage also become more and more important.Particularly, the power consumption element of transceiver maximum is the power amplifier with nonlinear characteristic.Yet to constant amplitude envelope signal (non-constant-envelope signals) when not modulating, it is high linear but to require power amplifier to have.Therefore, in wireless launcher, there is the problem that needs balance linearity and power-efficient.

Various power amplifier linearization technology have been used to improve wireless launcher neutral line and the existing problem of power-efficient.The LINC technology can be as a kind of transmitter architecture in order to increase the linearity and the power-efficient of wireless launcher.Because need to handle accurate signal and need be insensitive to manufacturing process variations, the digital LINC framework is more suitable for current processing demands.

Fig. 1 is the calcspar of existing LINC framework.Please refer to Fig. 1, the input signal S (t) of LINC 100 is constant amplitude envelope signal not.Demultiplexer (signal separator) 110 receiving inputted signal S (t) also are divided into two constant amplitude envelope signal S1 and S2.Then, power amplifier PA ₁And PA ₂Respectively constant amplitude envelope signal S1 and S2 are amplified.Because nonlinear power amplifier can use two high-power nonlinear power amplifiers with constant amplitude envelope signal linear amplification in this framework.At last, the signal after two amplifications is in power combiner (power combiner) 120 places combination.Like this, the output at power synthesizer can obtain the linear amplification signal.

The input signal S (t) of LINC system is constant amplitude envelope signal not,

S(t)＝A(t)·e ^j(t)

Wherein, the envelope of A (t) expression signal, the phase place of  (t) expression signal.Fig. 2 A is the phasor schematic diagram of input signal S (t).Constant amplitude envelope signal S (t) is not separated into constant amplitude envelope signal S ₁(t) and S ₂(t),

$S\left(t\right)=\frac{1}{2}[S_1\left(t\right)+S_2\left(t\right)]$

And anti-phase parallactic angle θ (t) can be expressed as:

$\mathrm{\θ}\left(t\right)={\cos }^{-1}\left(\frac{A\left(t\right)}{r_0}\right)$

S1 (t) and S2 (t) are r at a radius all ₀Circle on, in existing LINC reflector, r ₀Be by the predefined convergent-divergent constant of system designer, because the anticosine of input range is [1,1], so r ₀Selection must satisfy following formula:

r ₀≥max(A(t))

Fig. 2 B is that signal is through the phasor schematic diagram after amplifying.Through the signal indication after amplifying is GS ₁(t) and GS ₂(t), wherein G is the voltage gain of power amplifier.In conjunction with to obtain signal  GS (t), signal  GS (t) is the linear amplification of output signal S (t) by power combiner for two signals.Because anti-phase parallactic angle technology, LINC has realized linear amplification by two high power nonlinear amplifiers.

Summary of the invention

Therefore, need to propose to solve the needs that exist in the wireless launcher and weigh problem linear and power-efficient.

The present invention proposes a kind of multistage LINC reflector, comprising: the multilevel signal separator, and it comprises multistage scaler and converts input signal to phase signal; The phase modulated module is coupled to the multilevel signal separator, the receiving phase signal; Predistorter is coupled to the multilevel signal separator, produces envelope signal; Frequency mixing module is coupled to phase modulated module and predistorter, produces intermediate-freuqncy signal; The upconverter module is coupled to frequency mixing module, and will convert rf frequency on the intermediate-freuqncy signal to; And radio-frequency module, comprising a plurality of power amplifiers, power amplifier is coupled to the upconverter module, and power combiner, is coupled to power amplifier.

The present invention also proposes a kind of multistage LINC reflector, comprising: the multilevel signal separator, and it comprises multistage scaler and converts input signal to phase signal; Predistorter is coupled to the multilevel signal separator, produces envelope signal; Polar coordinates are coupled to the multilevel signal separator and put compensator to the IQ modular converter; The upconverter module is coupled to polar coordinates to the IQ modular converter; And radio-frequency module, comprising a plurality of power amplifiers, these power amplifiers are coupled to the upconverter module, and power combiner, are coupled to these power amplifiers.

Multistage LINC reflector provided by the invention can improve the service efficiency of power supply when satisfying linear the requirement.

Description of drawings

Fig. 1 is the calcspar of existing LINC framework.

Fig. 2 A is the phasor schematic diagram before input signal S (t) and composition thereof amplify.

Fig. 2 B is the phasor schematic diagram after input signal S (t) and composition thereof amplify.

Fig. 3 is the calcspar of the multistage LINC reflector of the embodiment of the invention.

Fig. 4 A is the phasor schematic diagram of the anti-phase parallactic angle θ (t) of single level zoom technology.

Fig. 4 B is anti-phase parallactic angle θ ' the phasor schematic diagram (t) of 2 grades of zoom technology.

Fig. 5 A and Fig. 5 B are respectively the detailed phasor schematic diagram and the summary phasor schematic diagram of the anti-phase parallactic angle of multistage zoom technology.

Fig. 6 is the envelope distribution map of WCDMA.

Fig. 7 A to Fig. 7 C is respectively the Signal Separation of the embodiment of the invention and the phasor schematic diagram of amplification.

Fig. 8 A is for satisfying the disclosed system block diagrams of a restrictive condition.

Fig. 8 B is that the signal of power amplifier output is G _NM _NWith multistage envelope R _NProportional schematic diagram.

Fig. 8 C is the transformation curve figure of power amplifier.

Fig. 8 D shows the output signal and the multistage envelope R of power amplifier _NThe curve chart of proportional relation.

Fig. 9 is the calcspar of the multistage scaler of one embodiment of the invention.

Figure 10 is the calcspar of the multistage LINC reflector of another embodiment of the present invention.

Embodiment

Fig. 3 is the calcspar of the multistage LINC reflector of the embodiment of the invention.Please refer to Fig. 3, multistage LINC reflector 300 comprises multilevel signal separator (multilevel signal component separator) 310, phase modulated module 320, frequency mixing module 340, upconverter module (up-converter block) 350, predistorter 360 and radio frequency (RF) module 330.Multilevel signal separator 310 comprises polar converter (polar converter) 311, multistage scaler (multilevel scaler) 313 is coupled to polar converter 311, anticosine module (inverse cosine module) 315 is coupled to multistage scaler 313, and phase calculator (phase calculator) 317 is coupled to polar converter 311 and anticosine module 315.Polar converter 311 receiving inputted signal S (t) also convert thereof into polar form.Then, the envelope A (t) of input signal S (t) handles by multistage scaler 313, and anticosine module 315 generates anti-phase parallactic angle θ ' (t).Then, phase calculator 317 generate phase signal  (t)+θ ' (t) and  (t)-θ ' (t).Particularly, multilevel signal separator 310 with input signal S (t) convert to phase signal  (t)+θ ' (t) and  (t)-θ ' (t).Phase modulated module 320 comprises two phase-modulators 321,322 that are coupled to multilevel signal separator 310.Predistorter 360 is coupled to multistage scaler 313 and phase calculator 317.Frequency mixing module 340 comprises two frequency mixers 341,342, is coupled to corresponding phase-modulator 321,322 respectively and is coupled to predistorter 360 jointly.Upconverter module 350 comprises two upconverters 351,352, is coupled to corresponding frequency mixer 341,342 respectively.The upconverter module generally can be realized by modulator or frequency mixer.Radio-frequency module 330 comprises a plurality of power amplifier (PA) 331 of upconverter module 350 and power combiners 333 that are coupled to power amplifier 331 of being coupled to.

The LINC reflector can adopt Wilkinson power combiner (wilkinsonpower combiner) in an embodiment of the present invention, and so it is not in order to limit the present invention.Other power combiner all is applicable to the present invention as harmless Wilkinson power combiner (lossless wilkinson power combiner), strange Li Kahua antiphase synthesizer (Chireix-outphasing combiner) or other fellow.

For the Wilkinson power combiner, efficiency factor η (t) can be defined as:

η(t)＝cos ²θ(t)

Anti-phase parallactic angle θ (t) can be expressed as:

$\mathrm{\θ}\left(t\right)={\cos }^{-1}\left(\frac{A\left(t\right)}{r_0}\right)$

It should be noted that θ (t) value and η (t) value are inversely proportional to.After anti-phase parallactic angle θ (t) was replaced by the formula of front, efficiency factor η (t) then can be expressed as:

$\mathrm{\η}\left(t\right)={\left(\frac{A\left(t\right)}{r_0}\right)}^2$

So, in order to utilize the power-efficient of Wilkinson power combiner, r ₀Value must near but be not less than the maximum of envelope A (t).

Please refer to Fig. 3, compared to the single level of existing use r ₀Zoom technology, the value that multistage scaler 313 reduces anti-phase parallactic angle θ (t) is with the power of the Wilkinson power combiner that obtains greater efficiency.Fig. 4 A is the phasor schematic diagram of the anti-phase parallactic angle θ (t) of single level zoom technology, and Fig. 4 B is anti-phase parallactic angle θ ' the phasor schematic diagram (t) of 2 grades of zoom technology.In this embodiment, compare r as envelope A (t) ₀When being much smaller, multistage scaler makes zoom factor from r ₀Be adjusted into r ₁, anti-phase parallactic angle θ ' (t) is much smaller than the single anti-phase parallactic angle θ of level (t) among Fig. 4 A in Fig. 4 B.So can utilize multistage zoom technology to strengthen the efficient of Wilkinson power combiner.Shown in Fig. 5 A, the progression in the multistage zoom technology can be N, and in Fig. 5 B, R _NBe the general expression formula of progression, wherein

R _N＝r _k，for?r _k+1＜A(t)≤r _k?k＝0，1，...，N-1

R wherein _N=0, r ₀=max (A (t)), then in multistage zoom technology to anti-phase parallactic angle θ ' being expressed as (t):

${\mathrm{\θ}}^{\′}\left(t\right)={\cos }^{-1}\left(\frac{A\left(t\right)}{R_N}\right).$

In order to make the maximizing efficiency of Wilkinson power combiner, need to use multistage zoom factor owing in the LINC reflector, so each grade r _kOptimum coefficient need pre-determine.The effectiveness formula of Wilkinson power combiner then can be expressed as:

$\mathrm{\η}\left(t\right)={\left(\frac{A\left(t\right)}{R_N}\right)}^2.$

Fig. 6 is the envelope distribution map of WCDMA, and wherein envelope A (t) is a probability function.In order to obtain the desired value of efficiency factor η (t), as shown in Figure 6, envelope A (t) can be divided into a plurality of zones, so just can obtain E (η (t)) by each regional desired value.The computing formula of E (η (t)) is $E\left(\mathrm{\η}\left(t\right)\right)=\underset{k=0}{\overset{k=N-1}{\mathrm{\Σ}}}{\∫}_{r_k}^{r_{k+1}}p\left(A\left(t\right)\right)\·{\left(\frac{A\left(t\right)}{r_k}\right)}^2\mathrm{dA}\left(t\right),$ Wherein p (A (t)) is the probability density function of A (t), r _kBe the zoom factor of K level, N is a convergent-divergent progression, and max (A (t)) is the maximum of input signal envelope.In order to make the maximizing efficiency of Wilkinson power combiner, E (η (t)) is carried out differential, make $\frac{\∂E\left(\mathrm{\η}\left(t\right)\right)}{\∂R_N}=0,$ K=0 wherein, 1 ..., N.So just, can obtain most preferred R _NSet.By most preferred multistage envelope R _NSet, multistage convergent-divergent just can make R _NDynamically near still being not less than envelope A (t).

When increasing the efficient of synthesizer by the multistage zoom technology of use, input signal can be separated into two and comprise multistage envelope R _NSignal, this way can be expressed as

Replace the division input signal to magnitude R _N, parameter M _NBe used to represent signal envelope.Please refer to Fig. 7 A, utilize R _NConvert little anti-phase parallactic angle θ ' to (t) with envelope information with input signal S (t).In Fig. 7 B, M _NMagnitude (magnitude) for signal.Multi-stage process is separated into two intermediate frequencies (intermediate signal) signal S with input signal S (t) ₁' (t) and S ₂' (t), its magnitude is M _NRather than R _NThis moment, signal can be expressed as S ₁' (t)=M _NE ^{J ( (t)+θ ' (t))}And S ₂' (t)=M _NE ^{J ( (t)-θ ' (t))}, by this magnitude M _NAnd multistage convergent-divergent progression just can obtain the power amplifier of higher-wattage.

After input signal separated, two upconverters were respectively with signal S ₁' (t) and S ₂' (t) be transformed into radio frequency (RF) frequency band.Signal on the process after the conversion can be expressed as: S _M1(t)=M _NCos (ω t+  (t)+θ ' (t)) and S _M2(t)=M _NCos (ω t+  (t)-θ ' (t)), Fig. 7 C are the schematic diagram after the signal process is amplified, and the signal after the amplification can be expressed as G _NS _M1(t) and G _NS _M2(t), wherein work as R _N=r _k, and k=0,1 ... during N-1, G _N=g _kG _NBe the gain of power amplifier, it is corresponding to different input envelope R _NThen, the signal after two in the LINC system synthesize is output as:

In order to realize linear amplification, output signal S _OutIt should be the constant of product A (t) cos (ω t+  (t)).As long as satisfy $\frac{\sqrt{2}\·G_N\·M_N}{R_N}=K,$ Just can realize high linear.Fig. 8 A is for satisfying the disclosed system block diagrams of this restrictive condition.Wherein this system comprises predistorter 810, receives multistage envelope R _NAnd generation envelope signal M _N, and power amplifier 820, be coupled to predistorter 810.The signal of power amplifier (PA) 820 outputs is G _NM _N, shown in Fig. 8 B, G _NM _NWith multistage envelope R _NProportional.If the signal G of power amplifier 820 outputs _NM _NWith multistage envelope R _NProportional, the multistage LINC reflector of then high linearity just can be realized.Fig. 8 C is the transformation curve figure of power amplifier.

Fig. 9 is the calcspar of the multistage scaler of one embodiment of the invention.Please consult Fig. 3 and Fig. 9 simultaneously, multistage scaler 313 comprises cutter (slicer) 510 and the read-only memory 530 that is coupled to cutter 510.Cutter 510 is used to select and export specific r _kTo anticosine module 315.Preferably, cutter 510 comprises comparator (comparator) (figure does not show).Comparator is determined the scope of envelope A (t) and is selected r according to the scope of envelope A (t) _kRead-only memory 530 stores the best R that can satisfy the curve corresponding relation among Fig. 8 D _NSet.Fig. 8 D shows the output signal and the R of power amplifier _NThe curve chart of proportional relation.

Figure 10 is the calcspar of the multistage LINC reflector of another embodiment of the present invention.Multistage LINC reflector 900 comprises multilevel signal separator 910, predistorter 950, and polar coordinates are to IQ modular converter (polar to IQ converter block) 920, upconverter module 940 and radio-frequency module 930.Multilevel signal separator 910 comprises polar converter 911, be coupled to the multistage scaler 913 of polar converter 911, be coupled to the anticosine module 915 of multistage scaler 913, and phase calculator 917, it is coupled to polar converter 911 and anticosine module 915.Polar converter 911 receiving inputted signal S (t) also convert thereof into polar form  (t).Then, envelope A (t) carries out convergent-divergent by multistage scaler 913, and anticosine module 915 produces anti-phase parallactic angle θ ' (t).Then, phase calculator 917 produce phase signal  (t)+θ ' (t) and  (t)-θ ' (t).In other words, multilevel signal separator 910 with input signal S (t) convert to phase signal  (t)+θ ' (t) and  (t)-θ ' (t).Predistorter 950 is coupled to multistage scaler 913 and produces envelope signal M _NPolar coordinates to IQ modular converter 920 comprises that two polar coordinates are to IQ transducer 921,922.Phase signal ψ (t)+θ ' (t) and ψ (t)-θ ' (t) and envelope signal M _NBe converted into rectangular coordinate system.Upconverter module 940 comprises two upconverters 941,942, is coupled to corresponding polar coordinates respectively to IQ transducer 921,922.Radio-frequency module 930 comprises a plurality of power amplifiers (PA) 931 that are coupled to upconverter module 940, and the power combiner 933 that is coupled to power amplifier 931.The concrete operations of the multistage LINC reflector among Figure 10 are similar to the description of Fig. 3, do not repeat them here.

Claims (12)

1. multistage linear amplification reflector with non-linear component comprises:

The multilevel signal separator comprises multistage scaler and converts input signal to phase signal;

The phase modulated module is coupled to described multilevel signal separator, receives described phase signal;

Predistorter is coupled to described multilevel signal separator, produces envelope signal;

Frequency mixing module is coupled to described phase modulated module and described predistorter, produces intermediate-freuqncy signal;

The upconverter module is coupled to described frequency mixing module, and will be converted to radio frequency band on the described intermediate-freuqncy signal; And

Radio-frequency module comprises a plurality of power amplifiers, and described a plurality of power amplifiers are coupled to described upconverter module, and power combiner, is coupled to described a plurality of power amplifier.

2. multistage linear amplification reflector with non-linear component according to claim 1 is characterized in that described multistage scaler comprises cutter and read-only memory, and described read-only memory is coupled to described cutter.

3. multistage linear amplification reflector with non-linear component according to claim 2 is characterized in that described cutter comprises comparator.

4. multistage linear amplification reflector with non-linear component according to claim 1 is characterized in that described power combiner is the Wilkinson power combiner.

5. multistage linear amplification reflector with non-linear component according to claim 1 is characterized in that described multilevel signal separator also comprises:

Polar converter is coupled to described multistage scaler, receives described input signal;

The anticosine module is coupled to described multistage scaler; And

Phase calculator is coupled to described polar converter and described anticosine module, produces described phase signal.

6. multistage linear amplification reflector with non-linear component according to claim 1 is characterized in that described upconverter module comprises a plurality of frequency mixers or modulator.

7. multistage linear amplification reflector with non-linear component comprises:

The multilevel signal separator comprises multistage scaler and converts input signal to phase signal;

Predistorter is coupled to described multilevel signal separator, produces envelope signal;

Polar coordinates are coupled to described multilevel signal separator and the described compensator of putting to the IQ modular converter;

The upconverter module is coupled to described polar coordinates to the IQ modular converter; And

Radio-frequency module comprises a plurality of power amplifiers, and described a plurality of power amplifiers are coupled to described upconverter module, and power combiner, is coupled to described a plurality of power amplifier.

8. multistage linear amplification reflector with non-linear component according to claim 7 is characterized in that described multistage scaler comprises cutter and read-only memory, and described read-only memory is coupled to described cutter.

9. multistage linear amplification reflector with non-linear component according to claim 8 is characterized in that described cutter comprises comparator.

10. multistage linear amplification reflector with non-linear component according to claim 7 is characterized in that described power combiner is the Wilkinson power combiner.

11. multistage linear amplification reflector with non-linear component according to claim 7 is characterized in that described multilevel signal separator also comprises:

Polar converter is connected to described multistage scaler, receives described input signal;

The anticosine module is coupled to described multistage scaler, and

Phase calculator is coupled to described polar converter and described anticosine module, produces described phase signal.

12. multistage linear amplification reflector with non-linear component according to claim 7 is characterized in that described upconverter module comprises a plurality of frequency mixers or modulator.

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