CN114006585A - Linear correcting device for radio frequency power amplifier - Google Patents
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Abstract
The invention relates to the technical field of digital predistortion, in particular to a radio frequency power amplifier linearization correction device, which comprises a signal source, a driving part, a radio frequency part and a digital signal processing unit, wherein the digital signal processing unit is used as a core of predistortion processing, the signal source, the driving part and the radio frequency part form a radio frequency channel, the radio frequency part sends an output signal to the digital signal processing unit through a feedback channel, the digital signal processing unit performs signal normalization, model matrix generation, parameter identification and predistortion signal generation on the feedback signal, and the generated predistortion signal feeds back the signal source; the invention realizes the predistortion processing of the digital signal processing unit by a digital signal processing method, and the digital signal processing unit can adopt programming control, thereby solving the problem of poor self-adaption in the pre-analog predistortion technology.
Description
Technical Field
The invention relates to the technical field of digital predistortion, in particular to a radio frequency power amplifier linearization correction device.
Background
The research on the power amplifier linearization technology at home and abroad has been long, and many methods are widely applied in the current radio frequency communication system, as shown in fig. 1, wherein the most important methods are: feed forward Linearization (Feedforward Linearization), Feedback Linearization (Feedback Linearization), Analog Predistortion (Analog Predistortion), and digital Predistortion. The above methods have advantages and disadvantages and applicable scenarios, and fig. 2 summarizes and compares the principles and features of each method.
The feedforward linearization technique is a post-compensation method for the nonlinearity of the power amplifier, and introduces an additional forward path to extract, reversely amplify and delay the distortion (including linear and nonlinear distortion) caused by the power amplifier, and then compensate the distortion to the output waveform. Because the single path is used for compensation at the output end of the power amplifier, the feedforward linearization method has good linearization effect, wide applicable bandwidth and no stability problem. However, the feedforward method strongly depends on the matching of two forward paths, and if any one of the gain, phase and delay of the error path and the power amplifier path is slightly mismatched, the linearization performance is rapidly reduced. On the other hand, the extra forward path also greatly increases the complexity and cost of the system.
The feedback linearization technique is based on the negative feedback principle in the automatic control theory, a feedback path is introduced between the input and the output of the power amplifier, and a negative feedback loop is constructed to inhibit the nonlinearity generated by the power amplifier. The feedback method has simple structure and is easy to realize, but because of the introduction of feedback, the gain, bandwidth and stability of the power amplifier are affected. Therefore, the feedback linearization method is applied narrowly, and is usually only used in a system with low frequency, narrow band and low linearity requirement.
The analog predistortion method introduces a predistorter at the input end of the power amplifier, and constructs an expansion characteristic curve corresponding to the compression characteristic of the power amplifier by using an analog device so as to counteract the nonlinear distortion caused by the gain compression of the power amplifier. The analog predistortion method has simple structure and low cost, but is difficult to accurately realize the expansion curve required by the power amplifier, and has poor linearization performance. Meanwhile, due to poor adaptability, the linearization effect of the optical fiber amplifier is likely to be further deteriorated under the influence of factors such as aging of components, environmental change, impedance adaptation and the like.
Digital predistortion techniques can be considered as an extension of analog predistortion methods in the digital domain in principle, but the field involved is more and the functions are more powerful. The development of power amplifier modeling and a digital signal processing system is benefited, accurate behavior level modeling of the radio frequency power amplifier in a digital domain becomes possible, and a digital predistortion technology is developed accordingly. By constructing an equivalent baseband model and an inverse model of the power amplifier in a digital system, proper distortion can be superposed on a useful signal in advance and then transmitted so as to counteract the distortion (linear distortion and nonlinear distortion) generated by the power amplifier. The digital predistortion technology can greatly play the potential of a digital system and solve the problem that a plurality of analog circuits are difficult to solve. The method has the characteristics of flexible configuration, easy integration and good self-adaption, and well ensures the linearization performance.
In summary, the digital predistortion technique brings its advantages, and has been widely used in the existing communication systems. At the same time, the potential that has not been mined also makes the development prospect in future communication systems the best.
From the time domain perspective, the mapping from the input voltage to the output voltage of the power amplifier can be described by a monotone nonlinear function, and the monotone function has an inverse function, so that the predistortion technology is based on the monotone nonlinear function, the mapping relationship of the input and the output of the predistortion module is adjusted to be exactly the inverse function of the mapping relationship of the power amplifier, as shown in fig. 3, and finally the integral mapping from the input to the output meets the relationship of the linear function.
From the perspective of the frequency domain, the nonlinear frequency domain of the power amplifier shows bandwidth broadening, which is because the power amplifier generates new frequency components due to the nonlinear characteristic, and the predistortion technique superimposes additional frequency components on the input signal through the predistortion module, adjusts the size of these superimposed components to make them exactly the same as the amplitude of the new frequency spectrum components generated by the power amplifier, and the phases are opposite, and finally these redundant frequency components cancel each other out, and the power amplifier output only retains the linear components with the same frequency as the original input, which is shown in fig. 3. It can be seen from the spectrum characteristics that the redundant spectrum components are partially superimposed on the linear spectrum components, so that the conventional rf filter has no effect on these spurs, and the predistortion technique can filter and remove the spurs having the same frequency as the input signal, so as to achieve the purpose of interference cancellation, which is also a great advantage of the predistortion technique.
The early predistortion technique is mainly implemented by an analog circuit, namely, a so-called analog predistortion technique (APD), in which a predistortion module is composed of analog nonlinear devices (including diodes, triodes, etc.), and the nonlinear response characteristic of the predistortion module is changed by adjusting parameters of the analog devices, although the analog circuit has a low cost, the structure of the predistortion circuit is complex and inconvenient to adjust, and particularly when the response characteristic of a power amplifier changes, the predistortion module cannot adaptively follow the power amplifier characteristic to change correspondingly, which also greatly limits the application range of the predistortion technique.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a linear rectification apparatus for a radio frequency power amplifier, which can use a digital circuit to replace a conventional analog predistortion circuit, and solve the problem of poor adaptation in the predistortion technique through programming control.
The invention relates to a radio frequency power amplifier linearization correction device, which comprises a signal source, a driving part, a radio frequency part and a digital signal processing unit, wherein the signal source, the driving part and the radio frequency part are sequentially connected, a feedback channel is arranged between the signal source and the radio frequency part, and the digital signal processing unit is arranged on the feedback channel;
the signal processing step of the digital signal processing unit includes:
(1) the signal normalization, the digital signal processing module obtains the output baseband signal through the sampling of the feedback channel, the digital signal processing module calculates the time delay between the output baseband signal and the signal generated by the signal source through the correlation of the input and the output, so as to compensate the delay on the time axis of the output signal caused by the transmitting channel and the feedback channel, and the supplementary formula is as follows:
wherein x (n) and y (n) are input and output baseband signals respectively, and the corresponding argument value is the time delay of the output signal when R (n0) takes the maximum value;
(2) generating a model matrix, wherein the behavior model of the predistortion module is as follows:
wherein x (n) is an input signal discrete sequence, y (n) is an output signal discrete sequence collected at the rear end of the power amplifier, p is a nonlinear order, and M is a memory depth;
(3) parameter identification, namely extracting parameters of a predistortion module by adopting a direct learning or indirect learning structure;
(4) and generating a predistortion signal, namely directly calculating an output signal according to a predistortion function, or storing the mapping relation of input and output of the behavior model into a lookup table, and directly looking up the table according to the input of the predistortion signal to obtain the predistortion signal.
Further, the indirect learning structure comprises a digital predistortion processing unit, a transmitting channel and a transmitter which are sequentially connected, wherein an input signal is input from the digital predistortion processing unit and is output from the transmitter; the digital predistortion processing unit directly obtains an inverse function of a power amplifier behavior model by acquiring input signals and output signals in a transmitting channel and an output end of a transmitter according to the relation that a predistortion module and a power amplifier are mutually inverse functions, and the obtained parameters are regarded as predistortion coefficients.
Furthermore, the direct learning structure comprises a digital pre-distortion processing unit, a transmitting channel and a transmitter which are connected in sequence, wherein an input signal is input from the digital pre-distortion processing unit and is output from the transmitter, a pre-distortion parameter extraction unit is arranged between the input end of the transmitter and the input end of the digital pre-distortion processing unit, the pre-distortion parameter extraction unit extracts the input signal from the output end of the digital pre-distortion processing unit, and acquires an output signal of the output end of the transmitter through a feedback channel; the predistortion parameter extraction unit sends the input signal and the output signal to the digital predistortion processing unit, and the digital predistortion processing unit updates the predistortion parameter according to the error of the input signal and the output signal, so that the error approaches to zero finally.
Furthermore, the digital signal processing unit is an FPGA programmable device.
The invention has the beneficial effects that: the invention relates to a radio frequency power amplifier linearization correction device, which uses a digital signal processing unit as a core of predistortion processing, wherein a signal source, a driving part and a radio frequency part form a radio frequency channel, the radio frequency part sends an output signal to the digital signal processing unit through a feedback channel, the digital signal processing unit performs signal normalization, model matrix generation, parameter identification and predistortion signal generation on the feedback signal, and feeds back the generated predistortion signal to the signal source; the invention realizes the predistortion processing of the digital signal processing unit by a digital signal processing method, and the digital signal processing unit can adopt programming control, thereby solving the problem of poor self-adaption in the pre-analog predistortion technology.
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In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that for a person skilled in the art, other relevant drawings can be obtained from the drawings without inventive effort:
fig. 1 is a schematic diagram of a prior art power amplifier linearization technique in the background art of the present invention;
FIG. 2 is a generalized diagram illustrating the features of the prior art in the background of the invention;
FIG. 3 is a diagram illustrating a mapping relationship in the prior art in the background art of the present invention;
FIG. 4 is a diagram of the hardware configuration of the present invention;
FIG. 5 is a schematic diagram of the structure of indirect learning according to the present invention;
FIG. 6 is a structural diagram of the direct learning of the present invention;
FIG. 7 is a schematic diagram illustrating a process of generating a predistortion signal by table lookup according to the present invention;
FIG. 8 is a schematic diagram illustrating an internal processing flow of the DSP unit according to the present invention;
FIG. 9 is a first illustration of a specific demonstration result of the present invention;
FIG. 10 is a second illustration of a specific demonstration result of the present invention;
fig. 11 is a third diagram illustrating a specific demonstration result of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
As shown in fig. 4: the radio frequency power amplifier linearization correction device of the embodiment mainly comprises a signal source, a driving part, a radio frequency part and a digital signal processing unit in the aspect of hardware, wherein the signal source, the driving part and the radio frequency part are sequentially connected;
the driving part is mainly a radio frequency driver; the radio frequency driver (RF driver) is a driver which adopts a quartz crystal oscillator and can output a fixed radio frequency signal with high stability and high accuracy; the driving part is used for generating an oscillating signal so as to drive a baseband signal generated by a signal source to transmit in a network with a specific frequency;
the radio frequency part adopts the most advanced RFTransceiverAD9009 radio frequency transceiver IC of ADI, and the whole RF part has the characteristics of ultrahigh integration level, flexibility and high performance. The chip supports a bandwidth of 100MHz for reception, 250MHz for transmission, and a RF reception transmission frequency range of 300MHz to 6 GHz.
The radio frequency part is connected with the driving part through a radio frequency channel, the radio frequency channel comprises a low noise amplifier LNA, a digital step attenuator DSA, a filter and a radio frequency gain amplifier GAINBLOCK, and the radio frequency part in the embodiment has excellent radio frequency performance due to the matching of the radio frequency transceiving IC and the radio frequency channel, and meanwhile, the radio frequency performance of the radio frequency part can be directly evaluated through an MMCX radio frequency interface. A DPD feedback channel (O) is reserved on the development board, so that a DPD algorithm is conveniently developed, and a radio frequency switch at a feedback end is used for starting an external correction function of the chip, so that better local oscillator correction performance can be obtained.
The digital signal processing unit adopts Xilinx new generation Zynq-7 series FPGA, has rich DSP and Logic resources, and is convenient to select according to specific project conditions. Related variable parameters (including function selection of each module in the FPGA, peripheral DSA chip attenuation, radio frequency transceiver chip frequency points and the like) can be directly modified on an upper computer through a serial port.
The digital signal processing unit is connected with the radio frequency part through a reserved DPD feedback channel, specifically, the feedback channel further comprises a filter, an LC filter, an analog-to-digital converter (ADC) and the like, which are not described in detail for the prior art, the digital signal processor acquires an output signal of a signal source processed by a driver, the radio frequency channel and the radio frequency part from the feedback channel, the digital signal processes the output signal to generate a preprocessed signal, and performs DPD algorithm correction on the signal of the signal source, so that the problem of output signal distortion is solved;
the processing method mainly comprises four steps of signal normalization, model matrix generation, parameter identification and predistortion signal generation, and the specific processing process is as follows:
s1: the signal normalization, the digital signal processing module obtains the output baseband signal through the sampling of the feedback channel, the digital signal processing module calculates the time delay between the output baseband signal and the signal generated by the signal source through the correlation of the input and the output, so as to compensate the delay on the time axis of the output signal caused by the transmitting channel and the feedback channel, and the supplementary formula is as follows:
in the formula (1), x (n) and y (n) are respectively the input baseband signal and the output baseband signal, and when R (n0) takes the maximum value, the corresponding argument value is the time delay of the output signal.
S2: and generating a model matrix, wherein the behavior model of the predistortion module is similar to the behavior model of the power amplifier in form, so that the model research of the digital predistortion technology mainly researches the nonlinear behavior model of the power amplifier, and in order to improve the practicability of the DPD technology, the constraint condition which should be met by the behavior model of the power amplifier in the digital predistortion technology is as follows: in order to facilitate the pre-distortion module to be realized by using a digital circuit, the input and the output of a power amplifier behavior model must be discrete signals; because the nonlinear distortion of the power amplifier comprises static nonlinearity and dynamic nonlinearity, the behavior model must also comprise the components of the static nonlinearity and the dynamic nonlinearity; in general, an input baseband signal of a power amplifier is a complex signal including two paths of I/Q signals, and therefore, a behavior model can be described by the complex signal; in order to facilitate the extraction of the model parameters using the least square method, the model output should satisfy a linear relationship with the model parameters. The behavior characteristic of the power amplifier can be abstracted into a nonlinear memory system, in the field of signal processing, the nonlinear memory system is usually described by a Volterra series, but the complete Volterra series is very complex, and the Volterra series is simplified by the Anding Zhu et al, and a DDR model is provided:
the formula (2) is a real number expression form of the DDR model, wherein x (n) is an input signal discrete sequence, y (n) is an output signal discrete sequence acquired at the rear end of the power amplifier, p is a nonlinear order, and M is a memory depth.
In practical applications, a complex expression form is often required, and equation (3) is a complex envelope form of the first-order DDR model obtained according to (2):
besides the DDR model, the power amplifier behavior model based on the simplified Volterra series also comprises an MP model, a GMP model and the like, which are commonly used in power amplifier modeling, and based on the models and an input signal sequence, a model matrix can be generated for parameter identification of the power amplifier behavior model.
S3: the parameters are identified, the behavior model of the predistortion module can be described by DDR, MP, GMP and other models, according to the principle of the digital predistortion technology, the parameters of the predistortion module should make the response of the parameters be the inverse function of the behavior model of the power amplifier, and the parameters can be extracted by a direct learning structure or an indirect learning structure:
as shown in fig. 5, the indirect learning structure includes a digital predistortion processing unit, a transmission channel and a transmitter connected in sequence, and an input signal is input from the digital predistortion processing unit and output from the transmitter;
the digital predistortion processing unit directly obtains an inverse function of a power amplifier behavior model by acquiring input signals and output signals in a transmitting channel and an output end of a transmitter according to the relation that a predistortion module and a power amplifier are mutually inverse functions, and the obtained parameters are regarded as predistortion coefficients; the indirect learning method is convenient to calculate, does not need iteration, has good real-time performance, but has higher requirement on the signal-to-noise ratio of the feedback signal.
As shown in fig. 6, the direct learning structure includes a digital predistortion processing unit, a transmitting channel and a transmitter connected in sequence, an input signal is input from the digital predistortion processing unit and output from the transmitter, a predistortion parameter extraction unit is arranged between an input end of the transmitter and an input end of the digital predistortion processing unit, the predistortion parameter extraction unit extracts the input signal from an output end of the digital predistortion processing unit and acquires an output signal of an output end of the transmitter through a feedback channel; the predistortion parameter extraction unit sends the input signal and the output signal to the digital predistortion processing unit, the direct learning structure is based on the self-adaptive filtering theory, and the digital predistortion processing unit updates the predistortion parameter according to the error of the input signal and the output signal, so that the error approaches to zero finally.
S4: the predistortion signal is generated, the final purpose of the digital predistortion technology is to obtain the predistortion signal and then use the predistortion signal as the input of the power amplifier, after the parameters of the predistortion module are obtained, the predistortion signal is calculated in two ways, one is to directly calculate the output signal according to the predistortion function, the other is to store the mapping relation of the input and the output of the behavior model into a lookup table (as shown in figure 7), the predistortion signal can be obtained according to the input direct lookup table, the former method adds and multiplies the operation and obviously increases the time complexity, and the latter method increases the storage resources, but the lookup operation takes less time, and the application is wider in the engineering practice.
As shown in fig. 8, in the flow of generating the predistortion signal by the digital signal processing unit, in the multi-stage nonlinear processing, the input signal in each stage is processed by the complex multiplier CM together with the respective input signal after the absolute value removal (IMC) and the table look-up (LUT) operations, and is finally output to the accumulator ACC, which outputs the output signal Yn.
As can be seen from the digital predistortion framework, on the basis of the original transmitter, the digital predistortion technology needs to add additional modules in both the analog domain and the digital domain, so the cost of the digital predistortion technology also includes the analog part and the digital part, and in addition, both the analog circuit and the digital circuit generate additional power consumption, which is also the overhead of the digital predistortion technology, and the sources of the cost overhead of these parts are described in detail below.
The analog part, the feedback path, is a major source of digital predistortion hardware cost. The bandwidth of the output signal is broadened due to the nonlinearity of the power amplifier, and usually, the power of a distortion component outside a third adjacent channel (above 7-order nonlinearity) is low, so that a feedback channel needs to acquire a nonlinear component below 5 th order without distortion, and at the moment, the feedback bandwidth is at least 5 times that of an original input signal, which causes a large cost pressure on devices such as an ADC and a mixer on the feedback channel, and the bandwidth of a predistortion signal is also broadened, so that the rate of the DAC is also required to reach 5 times or more of the bandwidth of the original signal, which also increases the hardware cost of the digital predistortion technology.
The parameter extraction is usually completed by using a least square method, and the time complexity is in direct proportion to the third power of the number of the model parameters, so that the parameter extraction consumes a larger time resource of the ARM module, in addition, the generation of the predistortion signal also consumes a certain time resource, and if the generation is realized by adopting a lookup table, a certain memory resource is consumed.
From the viewpoint of power consumption, the fundamental purpose of the digital predistortion technique is to reduce the power consumption of the rf circuit, so that the dc power can be converted into the rf power as much as possible for transmission, and therefore, the power consumption should be taken into consideration when measuring the cost benefit of the digital predistortion technique. The extra power consumption generated by digital predistortion mainly comes from an ADC (analog-to-digital converter) device and a DAC (digital-to-analog converter), and because a feedback channel is additionally introduced, the direct current power consumption generated by an ADC (analog-to-digital converter) acquisition signal is totally regarded as the power consumption overhead of the digital predistortion; although the original transmitter circuit includes a DAC device, after applying the predistortion technique, the bandwidth of the predistorted signal is widened compared with the bandwidth of the original communication signal, which requires that the sampling rate of the DAC is also increased by a multiple, and the higher the DAC rate is, the higher the power consumption is, so the digital predistortion technique also causes additional power consumption of the DAC, and in addition, the processes of delay alignment, parameter extraction and the like also generate certain digital power consumption.
The specific demonstration effect is as follows:
as shown in fig. 9-11, in the automatic calibration of digital predistortion, the intermodulation components generated by the respective nonlinearity of the two-tone signals (with an interval of 5MHz) are significantly suppressed, and through one DPD iteration, the intermodulation components can be reduced from the initial-34 dBc to-70 dBc, and the correction effect is good.
Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.
Claims (4)
1. The radio frequency power amplifier linearization orthotic devices, its characterized in that: the digital signal processing unit is arranged on the feedback channel;
the signal processing step of the digital signal processing unit includes:
(1) the signal normalization, the digital signal processing module obtains the output baseband signal through the sampling of the feedback channel, the digital signal processing module calculates the time delay between the output baseband signal and the signal generated by the signal source through the correlation of the input and the output, so as to compensate the delay on the time axis of the output signal caused by the transmitting channel and the feedback channel, and the supplementary formula is as follows:
wherein x (n) and y (n) are input and output baseband signals respectively, and the corresponding argument value is the time delay of the output signal when R (n0) takes the maximum value;
(2) generating a model matrix, wherein the behavior model of the predistortion module is as follows:
wherein x (n) is an input signal discrete sequence, y (n) is an output signal discrete sequence collected at the rear end of the power amplifier, p is a nonlinear order, and M is a memory depth;
(3) parameter identification, namely extracting parameters of a predistortion module by adopting a direct learning or indirect learning structure;
(4) and generating a predistortion signal, namely directly calculating an output signal according to a predistortion function, or storing the mapping relation of input and output of the behavior model into a lookup table, and directly looking up the table according to the input of the predistortion signal to obtain the predistortion signal.
2. The rf power amplifier linearization correction device of claim 1, wherein: the indirect learning structure comprises a digital predistortion processing unit, a transmitting channel and a transmitter which are sequentially connected, wherein an input signal is input from the digital predistortion processing unit and is output from the transmitter; the digital predistortion processing unit directly obtains an inverse function of a power amplifier behavior model by acquiring input signals and output signals in a transmitting channel and an output end of a transmitter according to the relation that a predistortion module and a power amplifier are mutually inverse functions, and the obtained parameters are regarded as predistortion coefficients.
3. The rf power amplifier linearization correction device of claim 1, wherein: the direct learning structure comprises a digital pre-distortion processing unit, a transmitting channel and a transmitter which are sequentially connected, wherein an input signal is input from the digital pre-distortion processing unit and output from the transmitter, a pre-distortion parameter extraction unit is arranged between the input end of the transmitter and the input end of the digital pre-distortion processing unit, the pre-distortion parameter extraction unit extracts an input signal from the output end of the digital pre-distortion processing unit and acquires an output signal of the output end of the transmitter through a feedback channel; the predistortion parameter extraction unit sends the input signal and the output signal to the digital predistortion processing unit, and the digital predistortion processing unit updates the predistortion parameter according to the error of the input signal and the output signal, so that the error approaches to zero finally.
4. The rf power amplifier linearization correction device of claim 1, wherein: the digital signal processing unit is an FPGA programmable device.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114553247A (en) * | 2022-04-08 | 2022-05-27 | 上海星思半导体有限责任公司 | Radio frequency circuit, and method and device for determining digital predistortion coefficient set |
| CN114650073A (en) * | 2022-04-15 | 2022-06-21 | 成都信息工程大学 | Linearization correction method and device for radio frequency receiver |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114553247A (en) * | 2022-04-08 | 2022-05-27 | 上海星思半导体有限责任公司 | Radio frequency circuit, and method and device for determining digital predistortion coefficient set |
| CN114553247B (en) * | 2022-04-08 | 2023-07-28 | 上海星思半导体有限责任公司 | Radio frequency circuit, method and device for determining digital predistortion coefficient set |
| CN114650073A (en) * | 2022-04-15 | 2022-06-21 | 成都信息工程大学 | Linearization correction method and device for radio frequency receiver |
| CN114650073B (en) * | 2022-04-15 | 2023-05-16 | 成都信息工程大学 | Linearization correction method and device for radio frequency receiver |
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