CN107948116B - Power amplifying device based on polar modulation - Google Patents

Abstract

An embodiment of the present invention provides a power amplifying device based on polar modulation, the power amplifying device includes: a decoder, a jitter generator, and a power amplifier module, the decoder is configured to The resolution of the power amplifier module acquires the quantization error of the power amplifier module, and sends the quantization error to the jitter generator; the jitter generator is configured to generate a second control signal according to the quantization error, and send the quantization error to the jitter generator. Two control signals are sent to the power amplifier module; the power amplifier module is configured to generate a jitter signal according to the second control signal to eliminate the quantization error, so as to complete the amplification of the modulated signal to be transmitted. By adding a jitter generator, and using the jitter generator to control the power amplifier module to generate a jitter signal according to the quantization error, the quantization error is eliminated, the resolution of the power amplifier device is improved under the condition that only one power amplifier subunit is added, and the structure is simple.

Description

Power Amplifier Based on Polar Modulation

technical field

Embodiments of the present invention relate to the field of communication technologies, and more particularly, to a power amplifying apparatus based on polarization modulation.

Background technique

In recent years, with the continuous improvement of people's demand for communication rates, wireless communication systems must meet people's needs under limited bandwidth, which leads to more and more complex modulation methods of the system. ratio is getting higher and higher. The traditional linear power amplifier can only meet the large amplitude conversion through the power back-off for the signal with the peak-to-average ratio. This will result in a sharp drop in power amplifier efficiency. For this reason, it is proposed to use a switch-type nonlinear power amplifier to realize linear amplification. The nonlinear power amplifier works in two states of switch and has high efficiency. Nonlinear power amplifiers usually use polar modulation.

In a typical nonlinear power amplifier scheme applying polar modulation, the power amplifier is composed of a series of parallel power amplifier sub-units, and whether the power amplifier sub-units work or not is controlled by the value of a decoder. The baseband I and Q signals are first converted into amplitude and phase signals. The phase signal is used as the driving signal to drive the on-off of the switch-type nonlinear power amplifier; the amplitude signal is used to control the number of working power amplifier sub-units after decoding. The number of working power amplifier sub-units is different, so that the output drive current changes, and signals of different amplitudes are generated.

In the above-mentioned power amplifier system based on polar modulation, the amplitude modulation accuracy depends on the number of power amplifier sub-units. The more the number, the finer and more accurate the amplitude change will be. However, the more subunits there are, the more complex the control module will be, reducing the overall efficiency; and the more subunits, the more difficult it is to ensure consistency.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a power amplifier device based on polarization modulation that overcomes the above problem or at least partially solves the above problem.

An embodiment of the present invention provides a power amplifying apparatus based on polar modulation, the power amplifying apparatus includes: a decoder, a jitter generator, and a power amplifier module, and the decoder, the jitter generator, and the power amplifier module The three are connected in sequence; among them,

The decoder is configured to generate a first control signal according to the amplitude signal of the modulation signal to be transmitted and the resolution of the power amplifier module, and obtain the amplitude signal of the power amplifier module according to the amplitude signal of the modulation signal to be transmitted and the resolution of the power amplifier module. quantization error, and sending the first control signal to the power amplifier module, and sending the quantization error to the jitter generator;

The jitter generator is configured to generate a second control signal according to the quantization error, and send the second control signal to the power amplifier module;

The power amplifier module is configured to control the amplification factor of the power amplifier module according to the first control signal, and generate a jitter signal according to the second control signal to eliminate the quantization error, so as to complete the amplification of the modulation signal to be transmitted .

Wherein, the power amplifier module includes at least two power amplifier sub-units, and the at least two power amplifier sub-units are connected in parallel; the jitter generator is connected to any one of the at least two power amplifier sub-units, The second control signal is used to send the second control signal to any one of the power amplifier sub-units, so as to control the on-off of the any one of the power amplifier sub-units.

The decoder is connected to other power amplifier sub-units in the at least two power amplifier sub-units, respectively, and is used for sending the first control signal to the other power amplifier sub-units in the at least two power amplifier sub-units, respectively. , so as to control the on-off of the other power amplifier sub-units, thereby controlling the magnification of the power amplifier module.

Wherein, when the second control signal is at a high level, any one of the power amplifier subunits is turned on; when the second control signal is at a low level, any one of the power amplifier subunits is turned off.

wherein, the jitter generator includes a look-up table and a counter; wherein,

The look-up table is used to obtain the counter count times corresponding to the period of the jitter signal according to the quantization error, and the counter count times corresponding to the conduction time of any one of the power amplifier sub-units in the period of the jitter signal, and sent to the counter;

The counter is configured to output the second control signal according to the counter count times corresponding to the period of the jitter signal and the counter count times corresponding to the conduction time of any one of the power amplifier subunits in the period of the jitter signal.

Wherein, the look-up table stores the correspondence between the quantization error and the counter count times corresponding to the period of the jitter signal, and the quantization error and any one of the power amplifiers in the period of the jitter signal. Correspondence between the counter count times corresponding to the on-time of the subunit.

Wherein, the following relationship is satisfied among the quantization error, the counter count times corresponding to the period of the jitter signal, and the counter count times corresponding to the conduction time of any one of the power amplifier sub-units in the period of the jitter signal :

Among them, A ₂ is the quantization error, ΔA is the resolution of the power amplifier module, k ₁ is the number of counter counts corresponding to the conduction time of any one of the power amplifier sub-units in one period of the jitter signal, k ₁ +k ₂ is the number of counter counts corresponding to the period of the jitter signal, and k ₁ and k ₂ are integers. If the values of k ₁ and k ₂ cannot make the two sides of the above formula equal, then k ₁ and k ₂ are taken to make the two sides of the above formula equal. The value with the smallest absolute value of the difference between the sides.

Wherein, the counter count times k ₁ +k ₂ corresponding to the period of the jitter signal cannot be infinite.

Wherein, the power amplifying device further includes a filter, the input end of the filter is connected to the output end of the power amplifier module, and is used for banding the amplified modulated signal to be transmitted output by the power amplifier module. pass filtering.

Wherein, the power amplifying device further includes a driving module, the output end of the driving module is connected with the input end of the power amplifying module, and the driving module is used for driving the power amplifying module.

The embodiment of the present invention provides a power amplifying device based on polarization modulation. By adding a jitter generator, and using the jitter generator to control the power amplifier module to generate a jitter signal according to the quantization error, the quantization error is eliminated, and only one power amplifier sub-unit is added. In this case, the resolution of the power amplifying device is improved, and the structure is simple.

Description of drawings

FIG. 1 is a schematic structural diagram of a power amplifying apparatus based on polarization modulation provided by an embodiment of the present invention;

2 is a schematic structural diagram of a jitter generator in an embodiment of the present invention;

3 is a schematic structural diagram of another power amplifying apparatus based on polarization modulation provided by an embodiment of the present invention;

4 is a Matlab simulation of the amplifying device described in FIG. 3 in an embodiment of the present invention, and the output waveform diagram of each key point is obtained when k ₁ =0;

FIG. 5 is a Matlab simulation of the amplifying device shown in FIG. 3 in an embodiment of the present invention, and the output waveform diagram of each key point is obtained when k ₁ =k ₂ =1;

FIG. 6 is a Matlab simulation of the amplifying device shown in FIG. 3 in an embodiment of the present invention, and an output waveform diagram of each key point is obtained when k ₁ =1, k ₂ =3.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are the Some, but not all, embodiments are disclosed. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

FIG. 1 is a schematic structural diagram of a power amplifying apparatus based on polarization modulation provided by an embodiment of the present invention. As shown in FIG. 1 , the power amplifying apparatus includes: a decoder 1, a jitter generator 2, and a power amplifier module 3, and The decoder 1 , the jitter generator 2 and the power amplifier module 3 are connected in sequence. in:

The decoder 1 is configured to generate a first control signal according to the amplitude signal of the modulated signal to be transmitted and the resolution of the power amplifier module 3, and obtain the received signal according to the amplitude signal of the modulated signal to be transmitted and the resolution of the power amplifier module 3. The quantization error of the power amplifier module 3 is sent, and the first control signal is sent to the power amplifier module 3 , and the quantization error is sent to the jitter generator 2 . The jitter generator 2 is configured to generate a second control signal according to the quantization error, and send the second control signal to the power amplifier module 3 . The power amplifier module 3 is used to control the amplification factor of the power amplifier module 3 according to the first control signal, and generate a jitter signal according to the second control signal to eliminate the quantization error, so as to complete the modulation signal to be transmitted. magnification.

The resolution of the power amplifier module 3 refers to the input amplitude value corresponding to each power amplifier sub-unit in the power amplifier module 3, and the input amplitude value corresponding to each power amplifier sub-unit is determined by the number of power amplifier sub-units. The basic strategy is to ensure that When all the power amplifier sub-units are turned on, it represents the maximum value of the input signal amplitude. Divide the maximum value of the input signal at this time by the number of all turned-on power amplifier sub-units, which is the input amplitude corresponding to each power amplifier sub-unit. value. The greater the number of power amplifier sub-units, the smaller the corresponding input amplitude value, and the higher the resolution of the corresponding power amplifier module 3 . The quantization error of the power amplifier module 3 refers to the difference between the actual amplitude of the modulated signal to be transmitted and the sum of the amplitudes corresponding to the turned-on power amplifier subunits controlled by the decoder 1 .

When the existing power amplifying device based on polar modulation amplifies the amplitude of the modulated signal, if there is a quantization error, it is necessary to increase the number of power amplifier subunits to improve the resolution of the power amplifier module 3 so as to eliminate the quantization error. However, the greater the number of power amplifier sub-units, the more complex the corresponding control module, and the lower the overall efficiency of the power amplifier device. To this end, the technical solution provided by the embodiments of the present invention is: without increasing the number of power amplifier subunits, a jitter generator 1 is added, and a jitter signal is generated in the power amplifier module 3 to reduce or eliminate quantization errors.

Specifically, the device further includes a signal input module 7 and a polar coordinate signal generator 6. The signal input module 7 is used for inputting a modulated signal to be transmitted. The signal is usually represented by Cartesian coordinates, including quadrature I and Q two signals. road signal. The polar coordinate signal generator 6 is used to convert a signal represented in Cartesian coordinates into a polar coordinate representation. The decoder compares the amplitude signal of the modulated signal to be transmitted sent by the polar coordinate signal generator 6 with the sum of the amplitudes corresponding to the turned-on power amplifier sub-units controlled by the decoder, and finds out the amplitude signal of the modulated signal to be transmitted and the amplitude of the modulated signal to be transmitted by the decoder. The difference between the amplitude sums corresponding to the power amplifier sub-units that are turned on is the quantization error. In actual operation, the number of power amplifier sub-units controlled by the decoder needs to be determined according to the amplitude signal of the modulated signal to be transmitted.

Then send the quantization error to the jitter generator, the jitter generator generates a second control signal according to the size of the quantization error, and then sends the second control signal to the power amplifier module, and the power amplifier module generates the jitter signal according to the second control signal to eliminate quantization errors. The whole process is the process in which the jitter generator controls the power amplifier module to generate a jitter signal according to the quantization error to eliminate the quantization error. In this process, there is no need to increase the number of power amplifier sub-units, so that the structure of the device is simple.

The embodiment of the present invention provides a power amplifying device based on polarization modulation. By adding a jitter generator, and using the jitter generator to control the power amplifier module to generate a jitter signal according to the quantization error, the quantization error is eliminated, and only one power amplifier sub-unit is added. In this case, the resolution of the power amplifying device is improved, and the structure is simple.

Based on the foregoing embodiment, as shown in FIG. 1 , the power amplifier module includes at least two power amplifier subunits, and the at least two power amplifier subunits are connected in parallel; the jitter generator is connected to the at least two power amplifier subunits. is connected to any one of the power amplifier sub-units, and is used for sending the second control signal to the any one of the power amplifier sub-units, so as to control the on-off of the any one of the power amplifier sub-units.

Specifically, the number of power amplifier subunits in the power amplifier module needs to be determined according to the amplitude value of the modulated signal to be transmitted. When the amplifying device provided in the embodiment of the present invention is often used to amplify a modulated signal to be transmitted in a certain amplitude range, a reasonable number of power amplifier subunits may be set accordingly.

The jitter generator only needs to be connected to one power amplifier sub-unit in the power amplifier module. It can also be understood that the jitter generator only needs to control one power amplifier sub-unit in the power amplifier module to generate a jitter signal to eliminate quantization errors. In specific implementation, the jitter generator controls the on-off of the power amplifier subunit connected to it according to the first control information to generate a jitter signal, and the jitter signal is superimposed with the output signals of other power amplifier subunits connected in parallel to eliminate quantization errors.

In the embodiment of the present invention, the jitter generator controls the on-off of any power amplifier sub-module in the power amplifier module according to the second control signal to generate a jitter signal, thereby eliminating the quantization error without increasing the number of power amplifier sub-units, and improving the resolution of the power amplifier device. Rate.

Based on the foregoing embodiment, the decoder is connected to other power amplifier sub-units in the at least two power amplifier sub-units, respectively, and is configured to send the first control signal to the other power amplifier sub-units in the at least two power amplifier sub-units, respectively. A power amplifier sub-unit to control the on-off of the other power amplifier sub-units.

Based on the above embodiment, when the second control signal is at a high level, any one of the power amplifier subunits is turned on; when the second control signal is at a low level, any one of the power amplifier subunits is turned off.

Based on the above embodiment, as shown in FIG. 2 , the jitter generator includes a look-up table 21 and a counter 22 . in:

The look-up table 21 is used to obtain the counter count times corresponding to the period of the jitter signal according to the quantization error, and the counter count times corresponding to the conduction time of any one of the power amplifier subunits in the period of the jitter signal, and sent to the counter. The counter 22 is configured to output the second control signal according to the counter count times corresponding to the period of the jitter signal and the counter count times corresponding to the conduction time of any one of the power amplifier sub-units in the period of the jitter signal. .

Based on the above embodiment, the look-up table stores the correspondence between the quantization error and the number of counter counts corresponding to the period of the dither signal, and the quantization error and the number of counts in the period of the dither signal. The corresponding relationship between the counter count times corresponding to the conduction time of any power amplifier subunit.

By pre-storing the corresponding relationship in the look-up table, the power amplifier can be made more efficient in the actual working process.

Based on the above embodiment, the quantization error, the counter count times corresponding to the period of the jitter signal, and the counter count times corresponding to the conduction time of any one of the power amplifier sub-units in the period of the jitter signal are among the three Satisfy the following relationship:

Among them, A ₂ is the quantization error, ΔA is the resolution of the power amplifier module, k ₁ is the number of counter counts corresponding to the conduction time of any one of the power amplifier sub-units in one period of the jitter signal, k ₁ +k ₂ is the number of counter counts corresponding to the period of the jitter signal, and k ₁ and k ₂ are integers. If the values of k ₁ and k ₂ cannot make the two sides of the above formula equal, then k ₁ and k ₂ are taken to make the two sides of the above formula equal. The value with the smallest absolute value of the difference between the sides.

Specifically, the carrier frequency of the modulated signal to be transmitted is ω _c , the carrier period is T, and the phase is φ. Then any one of the power amplifier sub-units connected to the jitter generator works on-off period is (k ₁ +k ₂ )T, wherein, the any one of the power amplifier sub-units is turned on within k ₁ T time, and at k ₂ T time off. The amplitude corresponding to any power amplifier sub-unit being turned off is A ₁ , the overall output amplitude corresponding to turning on is A ₁ +ΔA, the overall output amplitude corresponding to turning off is A ₁ , and ΔA represents the output amplitude corresponding to one power amplifier sub-unit . The on-off cycle of any power amplifier subunit connected to the jitter generator is (k ₁ +k ₂ )T, and the radio frequency signal corresponding to the on and off is expressed as:

u ₁ =(A ₁ +ΔA)cos(ω _c t+φ)

u ₂ =A ₁ cos(ω _c t+φ)

The switching power amplifier will convert the sine signal into the corresponding square wave signal in the actual work, and then filter out the high-order harmonics through band-pass filtering at the output, and only keep the fundamental wave. For the convenience of analysis, the fundamental wave is directly represented here instead of Consider harmonics. Then define the square wave signal as:

Then the output signal of the power amplifier module is:

u=u ₁ δ+u ₂ (1-δ)

=(A ₁ +ΔA)cos(ω _c t+φ)·δ+A ₁ cos(ω _c t+φ ₂ )·(1-δ)

The Taylor series of δ is expressed as:

Substitute the Taylor series of δ into the output signal expression to get:

外，其余部分都是高频、低频噪声，在通过滤波器后被滤除，整体系统的输出即为：Among them, except

In addition, the rest are high-frequency and low-frequency noise, which are filtered out after passing through the filter, and the output of the overall system is:

It can be seen that by increasing the amplitude jitter, the accuracy of the amplitude modulation can be increased, and the increased accuracy corresponds to A duty cycle proportional to the on-time of the dither power amplifier unit.

来计算量化误差与k₁和k₁+k₂之间的对应关系。在实际计算中，若k₁、k₂的取值无法使上述公式两侧相等，则k₁、k₂取使上述公式两侧的差值的绝对值最小的值。Therefore, it can be used

to calculate the correspondence between the quantization error and k ₁ and k ₁ +k ₂ . In actual calculation, if the values of k ₁ and k ₂ cannot make the two sides of the above formula equal, then k ₁ and k ₂ take the values that minimize the absolute value of the difference between the two sides of the above formula.

Further, the counter count times k ₁ +k ₂ corresponding to the period of the jitter signal cannot be infinite.

为了防止相位抖动带来带内噪声，在设计抖动生成器的时候，必须保证该

在系统的通带之外。该要求要求k₁+k₂不能无限大，也就限制了幅度抖动提高幅度精度的能力。Specifically, among the high-frequency and low-frequency components, the component closest to the carrier frequency is

In order to prevent in-band noise from phase jitter, the jitter generator must be designed to ensure that this

outside the passband of the system. This requirement requires that k ₁ +k ₂ cannot be infinite, which limits the ability of amplitude jitter to improve amplitude accuracy.

Further, the power amplifying device also includes a filter 4, the input end of the filter 4 is connected with the output end of the power amplifier module 3, and is used for the amplified output of the power amplifier module 3 to be The transmit modulated signal is band-pass filtered.

Further, the power amplifying device further includes a driving module 5 , the output end of the driving module 5 is connected to the input end of the power amplifying module 3 , and the driving module 5 is used for driving the power amplifying module 5 .

The beneficial effects of the power amplifying apparatus based on polarization modulation provided by the embodiments of the present invention are further described below through a simulation example.

The embodiment of the present invention is verified by using Matlab. The Matlab simulation model is shown in FIG. 3 . In order to simplify the model, the number of power amplifier subunits in the power amplifier module is 1, and there is one dithering power amplifier subunit at the same time. Assuming that the carrier signal period is T, the gain of a power amplifier sub-unit is 10, and the input amplitude of the power amplifier sub-unit is 1, the output amplitude is 10, and the output signal of the power amplifier will have a gain loss after passing through the filter. Ideally, the corresponding filter The output amplitude gain corresponding to the last power amplifier sub-unit is U=6.365. Four points A, B, C and D in the model are selected as key points to verify the embodiment of the present invention.

As shown in Figure 4, when k ₁ =0, the dither power amplifier sub-unit is always turned off, and the waveform at each key point of the system is shown in Figure 4. The amplitude of the system output signal is U(6.365). Among them, the three points A, B, and C only show square waves for convenience.

As shown in FIG. 5 , when k ₁ =k ₂ =1, the turn-on and turn-off times of the dithering power amplifier sub-unit are T and T in one dither period. At this time, the waveform at each key point of the system is shown in Figure 5, and the output signal amplitude of the system is 1.5U (9.548).

As shown in FIG. 6 , when k ₁ =1, k ₂ =3, the turn-on and turn-off times of the dithering power amplifier sub-unit are T and 3T in one dither period. At this time, the waveform at each key point of the system is shown in Figure 6, and the output signal amplitude of the system is 1.25U (7.956).

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that it can still be The technical solutions described in the foregoing embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (8)

1. A power amplifying device based on polar modulation, the power amplifying device comprising: the device comprises a decoder, a jitter generator and a power amplifier module, wherein the decoder, the jitter generator and the power amplifier module are sequentially connected; wherein,

the decoder is used for generating a first control signal according to the amplitude signal of the modulation signal to be transmitted and the resolution of the power amplification module, acquiring the quantization error of the power amplification module according to the amplitude signal of the modulation signal to be transmitted and the resolution of the power amplification module, sending the first control signal to the power amplification module, and sending the quantization error to the jitter generator;

the jitter generator is used for generating a second control signal according to the quantization error and sending the second control signal to the power amplification module;

the power amplification module is used for controlling the amplification factor of the power amplification module according to the first control signal and generating a jitter signal according to the second control signal to eliminate the quantization error so as to finish the amplification of the modulation signal to be transmitted;

the power amplifier module comprises at least two power amplifier subunits, and the at least two power amplifier subunits are connected in parallel; the jitter generator is connected with any one of the at least two power amplifier subunits and is used for sending the second control signal to any one of the at least two power amplifier subunits so as to control the on-off of any one of the at least two power amplifier subunits;

the decoder is connected with other power amplifier subunits in the at least two power amplifier subunits respectively and is used for sending the first control signal to other power amplifier subunits in the at least two power amplifier subunits respectively so as to control the on-off of the other power amplifier subunits and further control the amplification factor of the power amplifier module.

2. The power amplifier device according to claim 1, wherein when the second control signal is at a high level, the any one of the power amplifier sub-units is turned on; and when the second control signal is at a low level, any one power amplifier subunit is switched off.

3. The power amplifying device according to claim 1, wherein the jitter generator includes a look-up table and a counter; wherein,

the lookup table is used for acquiring the counting times of a counter corresponding to the period of the jitter signal and the counting times of the counter corresponding to the conduction time of any one power amplifier subunit in the period of the jitter signal according to the quantization error, and sending the counting times to the counter;

the counter is used for outputting the second control signal according to the counting times of the counter corresponding to the period of the jitter signal and the counting times of the counter corresponding to the conduction time of any one power amplifier subunit in the period of the jitter signal.

4. The power amplifier according to claim 3, wherein the look-up table stores a correspondence between the quantization error and a count number of the counter corresponding to a period of the dither signal, and a correspondence between the quantization error and a count number of the counter corresponding to a turn-on time of the arbitrary power amplifier subunit within the period of the dither signal.

5. The power amplifier device according to claim 4, wherein the quantization error, the count of the counter corresponding to the period of the dither signal, and the count of the counter corresponding to the on-time of any one of the power amplifier sub-units in the period of the dither signal satisfy the following relationship:

wherein A is ₂For quantization error, Δ A is the power amplifier module resolution, k ₁The number of times, k, counted by a counter corresponding to the conduction time of any one power amplifier subunit in the period of the jitter signal ₁+k ₂The number of times is counted by a counter corresponding to the period of the jitter signal, and k ₁、k ₂Is an integer, if k ₁、k ₂K is determined such that the values of (A) cannot make both sides of the above formula equal ₁、k ₂Get and make the above-mentionedThe value at which the absolute value of the difference between the two sides of the equation is the smallest.

6. The power amplifier according to claim 5, wherein the period of the jitter signal corresponds to a counter count k ₁+k ₂Cannot be infinitely large.

7. The power amplifier device according to claim 1, further comprising a filter, wherein an input terminal of the filter is connected to an output terminal of the power amplifier module, and the filter is configured to perform band-pass filtering on the amplified modulation signal to be transmitted output by the power amplifier module.

8. The power amplifier device according to claim 1, further comprising a driving module, wherein an output terminal of the driving module is connected to an input terminal of the power amplifier module, and the driving module is configured to drive the power amplifier module.

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