CN103929134A - Power supply modulating method and device - Google Patents

Abstract

The embodiment of the invention provides a power supply modulating method and device applied to an enveloping tracking power amplifier. A direct current supply is modulated according to a preset form table function, and the modulated direct current supply is used for supplying power for the power amplifier. It is found by the applicant in the research that when the voltage value of the direct current supply and the square of the voltage value of an enveloping signal are in linearity in the preset forming table function, the bandwidth of the direct current supply is twice that of the enveloping signal, and thus it is clear that the power supply modulating method and device can significantly lower the bandwidth of the direct current supply under the situation that the bandwidth of enveloping signals are identical. Therefore, compared with the prior art, the power supply modulating method and device can be applied to communication systems with larger bandwidths, and thus the application range of the existing enveloping tracking power amplifier can be enlarged.

Description

A kind of power supply modulator approach and device

Technical field

The present invention relates to the communications field, relate in particular to a kind of power supply modulator approach and device.

Background technology

In envelope tracking power amplifier, use the DC power supply modulator that can follow the tracks of envelope variation, produce the direct current corresponding to envelope variation, thereby improve the efficiency of power amplifier.

And existing envelope tracking power amplifier, the bandwidth of its direct current supply voltage at least needs 3-4 times for envelope signal bandwidth, even 10 times, visible, between the bandwidth of direct current supply voltage and the bandwidth of envelope signal, there is the gap of at least 3 times, therefore, under the restriction of DC power supply modulator performance, the development trend day by day increasing along with communication system bandwidth, existing envelope tracking power amplifier can not use in the larger communication system of some bandwidth, thereby its scope of application is restricted, visible, the scope of application that how to expand envelope tracking power amplifier becomes current problem demanding prompt solution.

Summary of the invention

The embodiment of the present invention provides a kind of method of supplying power to and device, and object is to solve the problem of the scope of application that how to expand existing envelope tracking power amplifier.

To achieve these goals, the embodiment of the present invention provides following technical scheme:

A kind of power supply modulator approach, is applied to power amplifier, and described power amplifier is used for amplifying envelope signal, comprising:

According to default moulding table function, DC power supply to be modulated, the DC power supply after modulation is used to described power amplifier power supply, the linear function of the magnitude of voltage that described default moulding table function is described DC power supply and the power of described envelope signal.

Alternatively, the generation method of described default moulding table function comprises:

According to the physical characteristic between the magnitude of voltage of described DC power supply and the power output of described power amplifier and default function, generate described moulding table function, described default function obtains according to the characteristic curve of described power amplifier.

Alternatively, described default function comprises:

$v_s\stackrel{\mathrm{\Δ}}{=}f\left(x\right)=\left\{\begin{array}{c}{v}_{s\min },x\≤P_0\\ m\·{10}^{x/10}+n,\mathrm{else}\end{array}\right.$

Wherein, m, n are undetermined coefficient, v _sfor the magnitude of voltage of described DC power supply, V _sminfor the minimum supply power voltage of described DC power supply, P ₀for the peak power output corresponding to characteristic curve neutral line district of described power amplifier.

Alternatively, the physical characteristic between the magnitude of voltage of described DC power supply and the power output of described power amplifier comprises:

V _s=f (P _out+ C)=f (10log (G _linek ₁v ²)+C), wherein, v _sfor the magnitude of voltage of described DC power supply, v ²for the square value of the voltage of envelope signal, P _outfor the power output of described power amplifier, G _linefor the power of the described envelope signal overall gain after described power amplifier, C is horizontal offset.

Alternatively, described moulding table function comprises:

$\begin{array}{c}{v}_s=f(P_{\mathrm{out}}+C)\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ m\·{10}^{P_{\mathrm{out}}+C/10}+n,\mathrm{else}\end{array}\right.\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ \mathrm{\γm}\·{10}^{P_{\mathrm{out}}/10}+n,\mathrm{else}\end{array}\right.\end{array}$

Wherein, V _sminfor the minimum supply power voltage of described DC power supply, m, n are undetermined coefficient, γ=10 ^c/10.

Alternatively, in the time that the power output of power amplifier corresponding to described moulding table function is greater than the peak power output that described power amplifier can provide, described C is non-vanishing normal amount, otherwise described C is zero.

A kind of power supply modulator, is applied to power amplifier, and described power amplifier is used for amplifying envelope signal, comprising:

Modulating unit, according to default moulding table function, DC power supply is modulated, and the DC power supply after modulation is used to described power amplifier power supply, the linear function of the magnitude of voltage that described default moulding table function is described DC power supply and the power of described envelope signal.

Alternatively, also comprise:

Moulding table function generation unit, for the physical characteristic according between the magnitude of voltage of described DC power supply and the power output of described power amplifier and default function, generate described moulding table function, described default function obtains according to the characteristic curve of described power amplifier.

Alternatively, moulding table function generation unit specifically for:

According to v _s=f (P _out+ C)=f (10log (G _linek ₁v ²)+C) and $v_s\stackrel{\mathrm{\Δ}}{=}f\left(x\right)=\left\{\begin{array}{c}{v}_{s\min },x\≤P_0\\ m\·{10}^{x/10}+n,\mathrm{else}\end{array}\right.,$ Generate moulding table function $\begin{array}{c}{v}_s=f(P_{\mathrm{out}}+C)\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ m\·{10}^{P_{\mathrm{out}}+C/10}+n,\mathrm{else}\end{array}\right.\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ \mathrm{\γm}\·{10}^{P_{\mathrm{out}}/10}+n,\mathrm{else}\end{array}\right.\end{array},$

Wherein, v _sfor the magnitude of voltage of described DC power supply, v ²for the square value of the voltage of envelope signal, P _outfor the power output of described power amplifier, G _linefor the power of the described envelope signal overall gain after described power amplifier, C is horizontal offset, and m, n are undetermined coefficient, V _sminfor the minimum supply power voltage of described DC power supply, P ₀for the peak power output corresponding to characteristic curve neutral line district of described power amplifier, γ=10 ^c/10.

Alternatively, also comprise:

Amending unit, when be greater than the peak power output that described power amplifier can provide when the power output of power amplifier corresponding to described moulding table function, it is non-vanishing normal amount that described C is set, otherwise described C is zero.

The method of supplying power to that the embodiment of the present invention provides and device, according to default moulding table function, DC power supply is modulated, DC power supply after modulation is used to power amplifier power supply, because applicant finds under study for action, when in default moulding table function, the magnitude of voltage of DC power supply and the magnitude of voltage of envelope signal square be linearity time, the twice that bandwidth of described DC power supply is envelope signal, visible, power supply modulator approach of the present invention and device, in the situation that envelope signal bandwidth is identical, can significantly reduce the bandwidth of DC power supply, so, compared with prior art, can be applicable to the communication system that bandwidth is larger, thereby expand the scope of application of existing envelope tracking power amplifier.

Brief description of the drawings

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is the schematic diagram of the internal structure of the disclosed power amplifier of the embodiment of the present invention;

Fig. 2 is peak efficiency envelope-tracking curve chart;

Fig. 3 is the comparison diagram of the minimum bandwidth scheme of Nujira peak efficiency scheme (existing envelope-tracking amplifier technology) and this patent proposition;

Fig. 4 is that the embodiment of the present invention discloses in a kind of power supply modulator approach, the supply power voltage v in moulding table function _spower output P with power amplifier _outbe related to schematic diagram;

Fig. 5 is the structural representation that the embodiment of the present invention discloses a kind of power supply modulator;

Embodiment

The embodiment of the present invention solves existing envelope tracking power amplifier and can not be applicable to the problem of high bandwidth communication systems from the angle of moulding table.

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiment.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtaining under creative work prerequisite, belong to the scope of protection of the invention.

The disclosed a kind of power supply modulator approach of the embodiment of the present invention, is applied to power amplifier, and described power amplifier is used for amplifying envelope signal, and conventionally as shown in Figure 1, the method described in the present embodiment comprises the internal structure of power amplifier:

According to default moulding table function, DC power supply to be modulated, the DC power supply after modulation is used to described power amplifier power supply.

In the present embodiment, described default moulding table function comprises: the linear function of the magnitude of voltage of described DC power supply and the power of described envelope signal.

Applicant finds in research process: as the linear function of the voltage of the DC power supply power that is envelope signal, the twice that bandwidth of DC power supply is envelope signal.Concrete derivation is as follows:

The magnitude of voltage v of DC power supply _spower output P with envelope tracking power amplifier _outbetween exist relation as shown in Equation 1:

v _s＝f(P _out)

＝f(10log(G _linek ₁v ²)) (1)

Wherein, G _linefor the power of the envelope signal overall gain after power amplifier, k ₁for constant, represent power and envelope signal magnitude of voltage square linear factor, v ²for the magnitude of voltage of envelope signal square, i.e. the power of envelope signal.

Obviously,, to band-limited signal s (t), establishing its bandwidth is f _max, according to Fourier transform theory, can be expressed as:

$s\left(t\right)=\underset{i}{\mathrm{\Σ}}{\mathrm{\α}}_i\cos ({2\mathrm{\πf}}_{i}t+{\mathrm{\φ}}_i),\underset{i}{\max }{f}_i\≤f_{\max }$

Wherein f _ibe the frequency of i rank basic function, φ _ifor its phase place, therefore,

$\begin{array}{c}{s}^2\left(t\right)=\underset{k,i}{\mathrm{\Σ}}{\mathrm{\α}}_k{\mathrm{\α}}_i\cos ({2\mathrm{\πf}}_{k}t+{\mathrm{\φ}}_k)\cos ({2\mathrm{\πf}}_{i}t+{\mathrm{\φ}}_i)\\ =\frac{1}{2}\underset{k,i}{\mathrm{\Σ}}\left\{{\mathrm{\α}}_k{\mathrm{\α}}_i\cos \right[2\mathrm{\π}(f_k+f_i)t+({\mathrm{\φ}}_k+{\mathrm{\φ}}_i)]\\ +\cos [2\mathrm{\π}(f_k-f_i)t+({\mathrm{\φ}}_k-{\mathrm{\φ}}_i)]\}\end{array}$

Because $\underset{i}{\max }{f}_i\≤f_{\max },$ So

$\begin{array}{c}\underset{k,i}{\max }\{f_k+f_i,f_k-f_i\}\≤\underset{k}{\max }{f}_k+\underset{i}{\max }{f}_i\\ \≤{2f}_{\max }\end{array}$

Therefore signal s ²(t) bandwidth mostly is the twice of original signal most, i.e. 2f _max, and in above-mentioned formula (1), v _sfor v ²function, so, if direct current supply magnitude of voltage v _sfor envelope power v ²linear function, v _sbandwidth mostly be the twice of the bandwidth of v most.

The conclusion of utilizing above-mentioned derivation to obtain, power supply modulator approach described in the present embodiment, because the linear function of the magnitude of voltage that moulding table function is DC power supply and the power of envelope signal, therefore, the bandwidth of direct current supply voltage mostly is the twice of the bandwidth of envelope signal most, with the 3-4 of the bandwidth of the voltage of the DC power supply of the existing envelope tracking power amplifier voltage that is envelope signal doubly, even compare for 10 times, in the case of the bandwidth of envelope signal is identical, power supply modulator approach described in the present embodiment can be with lower power supply bandwidth power supply, that is to say, when method described in the present embodiment is applied on envelope tracking power amplifier, described envelope tracking power amplifier can amplify the envelope signal that bandwidth is larger, so, expand the scope of application of power amplifier.

In an embodiment of the present invention, the generation method of default moulding table function comprises: according to the physical characteristic between the magnitude of voltage of described DC power supply and the power output of described power amplifier and default function, generate described moulding table function, described default function obtains according to the characteristic curve of described power amplifier.Its detailed process is as follows:

(wherein minimum supply power voltage is V to the characteristic curve of foundation power amplifier as shown in Figure 2 _smin, maximum supply power voltage is V _smax, when minimum power supply, its linear zone gain is G ₀, peak power output corresponding to linear zone is P ₀, in Fig. 2, be about 20dBm), default function is:

$v_s\stackrel{\mathrm{\Δ}}{=}f\left(x\right)=\left\{\begin{array}{c}{v}_{s\min },x\≤P_0\\ m\·{10}^{x/10}+n,\mathrm{else}\end{array}\right.,$

Wherein, m, n is undetermined coefficient, x is power output variable, according to the physical characteristic between the magnitude of voltage of DC power supply and the power output of described power amplifier: v _s=f (P _out+ C)=f (10log (G _linek ₁v ²)+C) can obtain:

$\begin{array}{c}{v}_s\stackrel{\mathrm{\Δ}}{=}f(P_{\mathrm{out}}+C)\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ m\·{10}^{P_{\mathrm{out}}+C/10}+n,\mathrm{else}\end{array}\right.\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ m\·{10}^{\log \left(G_{\mathrm{line}}{k}_1{v}^2\right)}+n,\mathrm{else}\end{array}\right.\\ \left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ {\mathrm{kv}}^2+n,\mathrm{else}\end{array}\right.\\ \stackrel{\mathrm{\Δ}}{=}g\left(v\right)\end{array}$

Wherein, k=mk ₁g _line.Initial condition is:

$\left\{\begin{array}{c}{v}_{s\max }=m\·{10}^{P_{\mathrm{out}\max }/10}+n\\ v_{s\min }=m\·{10}^{P_0/10}+n\end{array}\right.$

Therefore:

$\left\{\begin{array}{c}m=\frac{v_{s\max }-v_{s\min }}{{10}^{P_{\mathrm{out}\max }/10}-{10}^{P_0/10}}\\ n=v_{s\min }-m\·{10}^{P_0/10}\end{array}\right.$

Therefore, the magnitude of voltage of DC power supply and the magnitude of voltage of envelope signal square relation, moulding table function g (v) is:

$\begin{array}{c}{v}_s\stackrel{\mathrm{\Δ}}{=}g\left(v\right)\\ =f(P_{\mathrm{out}}+C)\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ \mathrm{\γm}\·{10}^{P_{\mathrm{out}}/10}+n,\mathrm{else}\end{array}\right.\\ =\left\{\begin{array}{c}{v}_{s\min },\underset{v}{\arg }\{P_{\mathrm{out}}\≤P_0-C\}\\ {\mathrm{\γmk}}_1{G}_{\mathrm{line}}{v}^2+n,\mathrm{else}\end{array}\right.\end{array}$

Wherein, γ=10 ^c/10.

Utilize above-mentioned function g (v), be greater than P when power output is enlarged to gradually ₀time, DC power supply modulator is as long as at original magnitude of voltage V _sminthe voltage that one of upper stack and envelope voltage square value are linear, therefore, the twice that its bandwidth is former baseband signal bandwidth.

For example, in the time of C=0, for the power amplifier shown in Fig. 2, establish v _smax=4.5V, v _smin=1.5V, P ₀=20dBm, P _outmax=31dBm, according to above-mentioned moulding table function g (v), can obtain m=0.00259, n=1.24114.And then try to achieve the power output P that each supply voltage value is corresponding _out, the gain G of power amplifier _pA, original input signal envelope power Pre-P _in, the revised signal envelope power Post-P of digital pre-distortion _in, and digital pre-distortion gain G ain of DPD.Specifically in table 1.

Table 1

As can be seen from Table 1, overall gain is constant-gain, i.e. G ₀=P _out-Pre-P _in=26dB.Therefore, can ensure that after in conjunction with DPD algorithm, power amplifier is equivalent to Linear Power Amplifier.And there is equally the high efficiency feature of envelope tracking power amplifier, because contrast Fig. 2 can find, each numerical value is to { power output P _out, DC power supply voltage v _scorresponding point is substantially all saturation region point or transition region point, except power is lower than the situation of 20dBm.

Obviously, under same power output, direct current supply voltage lower (can not lower than the corresponding minimum voltage value of this power output), efficiency is higher.Fig. 3 is the comparison of the minimum bandwidth scheme of Nujira peak efficiency scheme (existing envelope-tracking amplifier technology) and this patent proposition, under same power output, and the voltage v of this programme _sbe a bit larger tham Nujira scheme, therefore efficiency must be lost, but because lower voltage must be less, particularly, in the time that power output is less than 29dBm, both voltage is almost identical, and therefore loss is also less.But the efficiency of power supply modulator can increase due to Bandwidth Reduction, thereby can make up the loss of a part of whole efficiency.

In above-mentioned moulding table function, m, n is determined by boundary condition respectively, contrast Fig. 3, under each supply power voltage, power amplifier has a limited output power, therefore may occur P _outexceed this supply power voltage v _sthe situation of lower peak power output, in the case, in the time of C=0, moulding table is invalid, for example, to the power amplifier shown in Fig. 2, establishes v _smax=4.5V, v _smin=1.5V, P ₀=22dBm, P _outmax=33dBm, according to above-mentioned moulding table function g (v), can obtain m=0.00163, n=1.24114.Supply power voltage v _swith power output P _outrelation as shown in Figure 4, obviously, because Nujira optimum efficiency power amplifier is except minimum voltage v _s, be all operated in saturation region outward, therefore can think the corresponding P of this situation lower curve _outfor maximum power amplifier power output.Therefore, can be found by Fig. 4, above-mentioned moulding table function is at some voltage v of some power amplifier _sunder exceeded the peak power output under this voltage, need to carry out correcting process.

In the time that C is non-vanishing normal amount, be equivalent to moulding table function, along the x axle side-play amount C that moves to left, to make the corresponding P of revised moulding table function _outbe less than or equal to maximum power amplifier power output.The curve of revised moulding table function as shown in Figure 4, m=0.00259, n=1.24114.It should be noted that the efficiency for ensureing power amplifier, when correction, C should get minimum value, just makes all P _outbe less than or equal to the value of maximum power amplifier power output, be 2 herein.

Visible, in above-mentioned one-tenth type function, v _sp _outdullness rise function, and boundary condition retrained minimum both sides' corresponding relation during with maximum of points, in conjunction with horizontal offset C, for any power amplifier, all has effective moulding table function.

The embodiment of the invention also discloses a kind of power supply modulator, be applied to power amplifier, described power amplifier is used for amplifying envelope signal, and as shown in Figure 5, described power supply modulator comprises:

Modulating unit 501, according to default moulding table function, modulates DC power supply;

Wherein, the DC power supply after modulation is used to described power amplifier power supply, the linear function of the magnitude of voltage that described default moulding table function is described DC power supply and the power of described envelope signal.

Alternatively, described power supply modulator also comprises:

Moulding table function generation unit 502, for the physical characteristic according between the magnitude of voltage of described DC power supply and the power output of described power amplifier and default function, generate described moulding table function, described default function obtains according to the characteristic curve of described power amplifier;

Described moulding table function generation unit can be specifically for:

Foundation

v _s＝f(P _out+C)＝f(10log(G _linek ₁v ²)+C)

With $v_s\stackrel{\mathrm{\Δ}}{=}f\left(x\right)=\left\{\begin{array}{c}{v}_{s\min },x\≤P_0\\ m\·{10}^{x/10}+n,\mathrm{else}\end{array}\right.,$

Generate moulding table function: $\begin{array}{c}{v}_s=f(P_{\mathrm{out}}+C)\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ m\·{10}^{P_{\mathrm{out}}+C/10}+n,\mathrm{else}\end{array}\right.\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ \mathrm{\γm}\·{10}^{P_{\mathrm{out}}/10}+n,\mathrm{else}\end{array}\right.\end{array},$

Wherein, v _sfor the magnitude of voltage of described DC power supply, v ²for the square value of the voltage of envelope signal, P _outfor the power output of described power amplifier, G _linefor the power of the described envelope signal overall gain after described power amplifier, C is horizontal offset, and m, n are undetermined coefficient, V _sminfor the minimum supply power voltage of described DC power supply, P ₀for the peak power output corresponding to characteristic curve neutral line district of described power amplifier, γ=10 ^c/10.

Amending unit 503, when be greater than the peak power output that described power amplifier can provide when the power output of power amplifier corresponding to described moulding table function, it is non-vanishing normal amount that described C is set, otherwise described C is zero.

Power supply modulator approach described in the present embodiment, because the linear function of the magnitude of voltage that moulding table function is DC power supply and the power of envelope signal, therefore, the bandwidth of direct current supply voltage mostly is the twice of the bandwidth of envelope signal most, with the 3-4 of the bandwidth of the voltage of the DC power supply of the existing envelope tracking power amplifier voltage that is envelope signal doubly, even compare for 10 times, in the case of the bandwidth of envelope signal is identical, power supply modulator approach described in the present embodiment can be with lower power supply bandwidth power supply, that is to say, when method described in the present embodiment is applied on envelope tracking power amplifier, power supply modulator described in the present embodiment, can expand the scope of application of existing power amplification musical instruments used in a Buddhist or Taoist mass.

If the function described in the present embodiment method realizes and during as production marketing independently or use, can be stored in a computing equipment read/write memory medium using the form of SFU software functional unit.Based on such understanding, the part that the embodiment of the present invention contributes to prior art or the part of this technical scheme can embody with the form of software product, this software product is stored in a storage medium, comprise that some instructions (can be personal computers in order to make a computing equipment, server, mobile computing device or the network equipment etc.) carry out all or part of step of method described in each embodiment of the present invention.And aforesaid storage medium comprises: USB flash disk, portable hard drive, read-only memory (ROM, Read-Only Memory), the various media that can be program code stored such as random access memory (RAM, Random Access Memory), magnetic disc or CD.

In this specification, each embodiment adopts the mode of going forward one by one to describe, and what each embodiment stressed is and the difference of other embodiment, between each embodiment same or similar part mutually referring to.

To the above-mentioned explanation of the disclosed embodiments, make professional and technical personnel in the field can realize or use the present invention.To be apparent for those skilled in the art to the multiple amendment of these embodiment, General Principle as defined herein can, in the situation that not departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention will can not be restricted to these embodiment shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.

Claims (10)

1. a power supply modulator approach, is applied to power amplifier, and described power amplifier is used for amplifying envelope signal, it is characterized in that, comprising:

According to default moulding table function, DC power supply to be modulated, the DC power supply after modulation is used to described power amplifier power supply, the linear function of the magnitude of voltage that described default moulding table function is described DC power supply and the power of described envelope signal.

2. method according to claim 1, is characterized in that, the generation method of described default moulding table function comprises:

According to the physical characteristic between the magnitude of voltage of described DC power supply and the power output of described power amplifier and default function, generate described moulding table function, described default function obtains according to the characteristic curve of described power amplifier.

3. according to the method shown in claim 2, it is characterized in that, described default function comprises:

$v_s\stackrel{\mathrm{\Δ}}{=}f\left(x\right)=\left\{\begin{array}{c}{v}_{s\min },x\≤P_0\\ m\·{10}^{x/10}+n,\mathrm{else}\end{array}\right.$

Wherein, m, n are undetermined coefficient, v _sfor the magnitude of voltage of described DC power supply, V _sminfor the minimum supply power voltage of described DC power supply, P ₀for the peak power output corresponding to characteristic curve neutral line district of described power amplifier.

4. according to the method in claim 2 or 3, it is characterized in that, the physical characteristic between the magnitude of voltage of described DC power supply and the power output of described power amplifier comprises:

V _s=f (P _out+ C)=f (10log (G _linek ₁v ²)+C), wherein, v _sfor the magnitude of voltage of described DC power supply, v ²for the magnitude of voltage of envelope signal square, P _outfor the power output of described power amplifier, G _linefor the power of the described envelope signal overall gain after described power amplifier, C is horizontal offset.

5. method according to claim 4, is characterized in that, described moulding table function comprises:

$\begin{array}{c}{v}_s=f(P_{\mathrm{out}}+C)\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ m\·{10}^{P_{\mathrm{out}}+C/10}+n,\mathrm{else}\end{array}\right.\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ \mathrm{\γm}\·{10}^{P_{\mathrm{out}}/10}+n,\mathrm{else}\end{array}\right.\end{array}$

Wherein, V _sminfor the minimum supply power voltage of described DC power supply, m, n are undetermined coefficient, γ=10 ^c/10.

6. method according to claim 5, it is characterized in that, in the time that the power output of power amplifier corresponding to described moulding table function is greater than the peak power output that described power amplifier can provide, described C is non-vanishing normal amount, otherwise described C is zero.

7. a power supply modulator, is applied to power amplifier, and described power amplifier is used for amplifying envelope signal, it is characterized in that, comprising:

Modulating unit, according to default moulding table function, DC power supply is modulated, and the DC power supply after modulation is used to described power amplifier power supply, the linear function of the magnitude of voltage that described default moulding table function is described DC power supply and the power of described envelope signal.

8. power supply modulator according to claim 7, is characterized in that, also comprises:

Moulding table function generation unit, for the physical characteristic according between the magnitude of voltage of described DC power supply and the power output of described power amplifier and default function, generate described moulding table function, described default function obtains according to the characteristic curve of described power amplifier.

9. power supply modulator according to claim 8, is characterized in that, moulding table function generation unit specifically for:

According to v _s=f (P _out+ C)=f (10log (G _linek ₁v ²)+C) and $v_s\stackrel{\mathrm{\Δ}}{=}f\left(x\right)=\left\{\begin{array}{c}{v}_{s\min },x\≤P_0\\ m\·{10}^{x/10}+n,\mathrm{else}\end{array}\right.,$ Generate moulding table function $\begin{array}{c}{v}_s=f(P_{\mathrm{out}}+C)\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ m\·{10}^{P_{\mathrm{out}}+C/10}+n,\mathrm{else}\end{array}\right.\\ =\left\{\begin{array}{c}{v}_{s\min },P_{\mathrm{out}}\≤P_0-C\\ \mathrm{\γm}\·{10}^{P_{\mathrm{out}}/10}+n,\mathrm{else}\end{array}\right.\end{array},$

Wherein, v _sfor the magnitude of voltage of described DC power supply, v ²for the square value of the voltage of envelope signal, P _outfor the power output of described power amplifier, G _linefor the power of the described envelope signal overall gain after described power amplifier, C is horizontal offset, and m, n are undetermined coefficient, V _sminfor the minimum supply power voltage of described DC power supply, P ₀for the peak power output corresponding to characteristic curve neutral line district of described power amplifier, γ=10 ^c/10.

10. power supply modulator according to claim 9, is characterized in that, also comprises:

Amending unit, when be greater than the peak power output that described power amplifier can provide when the power output of power amplifier corresponding to described moulding table function, it is non-vanishing normal amount that described C is set, otherwise described C is zero.