Analog predistortion processing circuit and signal processing device

Abstract

The present invention relates to an analog pre-distortion processing circuit and a signal processing device. The analog pre-distortion processing circuit includes a narrowband spread spectrum module, an analog pre-distortion module, and a filtering module. The narrowband spread spectrum module is used to spread spectrum the input narrowband radio frequency signal into a broadband radio frequency signal. The bandwidth of the broadband radio frequency signal is a preset bandwidth. The analog pre-distortion module is used to perform analog pre-distortion linearization processing on the broadband radio frequency signal to obtain a linearized broadband radio frequency signal; the preset bandwidth is within the optimal cancellation bandwidth of the analog pre-distortion module. The filtering module is used to perform signal filtering on the linearized broadband radio frequency signal to obtain a linearized narrowband radio frequency signal. The analog pre-distortion linearization processing of the narrowband radio frequency signal is realized, and the cancellation ability of the analog pre-distortion system for the narrowband radio frequency signal is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and particularly to an analog predistortion processing circuit and a signal processing device. Background Art

[0002] With the rapid development of mobile communication technologies, 4G and 5G communication systems have gradually become the mainstream, which has also made the wireless communication frequency band increasingly crowded and the peak-to-average ratio (PAR) of signals higher and higher. In order to accommodate more communication channels within a limited frequency spectrum range, transmission technologies with high spectrum utilization rate are required. However, due to the non-linearity of the power amplifier itself, it will interfere with other communication channels within the communication frequency band and affect the spectrum utilization rate. Therefore, in order to solve the problems of spectrum utilization rate and the non-linearity of the power amplifier, the commonly used solutions in the industry are mainly the CFR peak clipping technology and the linearization technology of the power amplifier.

[0003] Among them, the analog predistortion technology in the linearization technology of the power amplifier has an important application position and plays a key role in modern wireless communication. However, in the process of implementing the present invention, the inventor found that the traditional analog predistortion system has poor cancellation ability for narrowband RF signals. Summary of the Invention

[0004] Based on this, in view of the above problems existing in the traditional analog predistortion system, it is necessary to provide an analog predistortion processing circuit and a signal processing device.

[0005] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0006] On the one hand, the embodiments of the present invention provide an analog predistortion processing circuit, including:

[0007] A narrowband spreading module, configured to spread the input narrowband RF signal into a broadband RF signal; the bandwidth of the broadband RF signal is a preset bandwidth;

[0008] An analog predistortion module, configured to perform analog predistortion linearization processing on the broadband RF signal to obtain a linearized broadband RF signal; the preset bandwidth is within the optimal cancellation bandwidth of the analog predistortion module;

[0009] A filtering module, configured to perform signal filtering on the linearized broadband RF signal to obtain a linearized narrowband RF signal.

[0010] In one of the embodiments, the narrowband spreading module includes a combiner and a spreading signal source. The first input port of the combiner is used to receive the narrowband RF signal, and the second input port of the combiner is connected to the output end of the spreading signal source;

[0011] The spread spectrum signal source is used to output a broadband signal with a target bandwidth to the combiner after receiving an indication signal output by the main controller of the predistortion system. The combiner is used to combine the broadband signal with the narrowband radio frequency signal and output the obtained broadband radio frequency signal to the analog predistortion module.

[0012] In one embodiment, the narrowband spread spectrum module further includes a first coupler, a power detector, and a first power attenuator;

[0013] The input port of the first coupler is used to receive the narrowband radio frequency signal. The output port of the first coupler is connected to the first input port of the combiner. The coupling port of the first coupler is connected to the input port of the power detector. The input end of the first power attenuator is connected to the output end of the spread spectrum signal source, and the output end of the first power attenuator is connected to the second input port of the combiner;

[0014] The power detector is used to detect the signal power of the narrowband radio frequency signal and transmit it to the main controller. The first power attenuator is used to attenuate the signal power of the passed broadband signal to be less than the signal power of the narrowband radio frequency signal after receiving the power adjustment signal output by the main controller.

[0015] In one embodiment, the narrowband spread spectrum module further includes a first radio frequency switch and a second radio frequency switch;

[0016] The moving contact of the first radio frequency switch is used to access the narrowband radio frequency signal. The first stationary contact of the first radio frequency switch is connected to the input port of the first coupler. The second stationary contact of the first radio frequency switch is connected to the first stationary contact of the second radio frequency switch;

[0017] The second stationary contact of the second radio frequency switch is connected to the combining port of the combiner. The moving contact of the second radio frequency switch is connected to the input port of the analog predistortion module.

[0018] In one embodiment, the filtering module is a filter. The input port of the filter is connected to the output port of the analog predistortion module. The output port of the filter is used to output the linearized narrowband radio frequency signal externally.

[0019] In one embodiment, the above analog predistortion processing circuit further includes a third radio frequency switch,

[0020] The moving contact of the third radio frequency switch is connected to the output port of the analog predistortion module. The first stationary contact of the third radio frequency switch is connected to the input port of the filter. The second stationary contact of the third radio frequency switch is used to output the unspread and linearized broadband radio frequency signal externally.

[0021] In one embodiment, the analog predistortion module includes a power conversion circuit, a second coupler, a delay line, a third coupler, a radio frequency power amplifier, a fourth coupler, an isolator, a first balun, an analog predistortion chip, a second balun, and a third balun;

[0022] The power conversion circuit, the second coupler, the delay line, the third coupler, the radio frequency power amplifier, the fourth coupler, and the isolator are connected in series in sequence. The input port of the power conversion circuit is connected to the output port of the narrowband spread spectrum module, and the output port of the isolator is connected to the input port of the filtering module;

[0023] The coupling port of the second coupler is connected to the input port of the analog predistortion chip through the first balun, and the output port of the analog predistortion chip is connected to the coupling port of the third coupler through the second balun;

[0024] The coupling port of the fourth coupler is connected to the feedback input port of the analog predistortion chip through the third balun.

[0025] In one embodiment, the power conversion circuit includes a second power attenuator and a low-power amplifier tube;

[0026] The second power attenuator and the low-power amplifier tube are connected in series. The input port of the second power attenuator is connected to the output port of the narrowband spread spectrum module, and the output port of the low-power amplifier tube is connected to the input port of the second coupler.

[0027] On the other hand, a signal processing device is further provided, which includes the above-mentioned analog predistortion processing circuit.

[0028] In one embodiment, the above-mentioned signal processing device further includes a main controller. The narrowband spread spectrum module of the analog predistortion processing circuit includes a spread spectrum signal source, a power detector, and a first power attenuator;

[0029] The main controller is used to output an indication signal to the spread spectrum signal source, and is used to receive the signal power transmitted by the power detector and output a power adjustment signal to the first power attenuator.

[0030] In one embodiment, the analog predistortion processing circuit further includes a third radio frequency switch, and the narrowband spread spectrum module further includes a first radio frequency switch and a second radio frequency switch;

[0031] The main controller is electrically connected to the switch control ends of the first radio frequency switch, the second radio frequency switch, and the third radio frequency switch respectively, and the main controller is further used to output switch control signals to the first radio frequency switch, the second radio frequency switch, and the third radio frequency switch respectively.

[0032] In one embodiment, the signal processing device is any one of a baseband amplifier device, a repeater device, a radio frequency remote unit device, a track power amplifier device, an integrated power amplifier, and a receiver.

[0033] One of the above technical solutions has the following technical effects:

[0034] In the above analog pre-distortion processing circuit and signal processing device, by adopting a narrowband spread-spectrum module and a filtering module and performing circuit optimization design with the analog pre-distortion module, when the input radio frequency signal is a narrowband radio frequency signal, the narrowband radio frequency signal can be spread-spectrum to a broadband radio frequency signal with a bandwidth within the optimal cancellation bandwidth of the analog pre-distortion module. Furthermore, the analog pre-distortion module can perform normal and effective analog pre-distortion linearization processing on the broadband radio frequency signal. Finally, by filtering the broadband radio frequency signal after analog pre-distortion linearization processing, the spread-spectrum component in the broadband radio frequency signal can be removed to obtain the linearized narrowband radio frequency signal, realizing the analog pre-distortion linearization processing of the narrowband radio frequency signal, and greatly improving the cancellation ability of the analog pre-distortion system for the narrowband radio frequency signal. Description of the Drawings

[0035] Figure 1 It is a waveform schematic diagram of the existing analog pre-distortion processing technology;

[0036] Figure 2 It is a schematic circuit diagram of the existing analog pre-distortion processing system;

[0037] Figure 3 It is a first schematic diagram of the analog pre-distortion processing circuit in an embodiment;

[0038] Figure 4 It is a second schematic diagram of the analog pre-distortion processing circuit in an embodiment;

[0039] Figure 5 It is a third schematic diagram of the analog pre-distortion processing circuit in an embodiment;

[0040] Figure 6 It is a fourth schematic diagram of the analog pre-distortion processing circuit in an embodiment;

[0041] Figure 7 It is a fifth schematic diagram of the analog pre-distortion processing circuit in an embodiment;

[0042] Figure 8 It is a sixth schematic diagram of the analog pre-distortion processing circuit in an embodiment;

[0043] Figure 9 It is a seventh schematic diagram of the analog pre-distortion processing circuit in an embodiment:

[0044] Figure 10 It is a schematic diagram of the analog pre-distortion processing circuit structure of the signal processing device in an embodiment. Detailed implementation manners

[0045] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0046] It should be noted that unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific implementation manners and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0047] The radio frequency power linearization technology is widely applied in various industries such as communication, medical treatment and transportation. In some application scenarios, strict requirements are imposed on the linearity of radio frequency power amplifiers. In order to improve the linearity of radio frequency power amplifiers, linearization technologies are usually adopted. The main implementation manners of this linearization technology are as follows: implemented by using the power back-off technology, implemented by using the feed-forward technology, implemented by using the analog pre-distortion technology or implemented by using the digital pre-distortion technology.

[0048] Regarding the analog pre-distortion technology, its analog pre-distortion (APD) is one of the most basic building blocks in current wireless communication systems and is used to improve the efficiency of radio frequency power amplifiers. By reducing the distortion generated when the radio frequency power amplifier operates in its non-linear region, the efficiency and linearity of the radio frequency power amplifier can be greatly improved. Analog pre-distortion performs pre-distortion processing of signals in the analog domain without digitizing the signals, and has the advantages of small time delay and low cost compared with digital pre-distortion systems. Generally speaking, pre-distortion is to artificially add a system whose characteristics are exactly opposite to the non-linear distortion of the system including the power amplifier, so as to compensate for the gain and phase changes within the entire power change range of the input signal, and has characteristics such as good linearization effect, flexible design and strong applicability. When used in combination with Doherty power amplifiers, the efficiency of the analog pre-distortion system can be maximized, so it has gradually become the mainstream of current linearization technologies and plays a key role in modern wireless communication.

[0049] Such as Figure 1The waveform schematic diagram in the analog predistortion system is shown. Among them, after two symmetrical PA curves (i.e., power amplifier curves) are superimposed, the highly linear curve on the right side of the equal sign can be obtained, that is, the linearized curve output after analog predistortion processing. When the power amplifier operates in the nonlinear region, output compression will result in AM-AM and AM-PM distortion curves. The work of the APD is to output curves in the opposite directions of AM-AM and AM-PM, so as to achieve the effect of predistortion. According to the nonlinear characteristics (amplitude and phase distortion) of the power amplifier, the signals input to the power amplifier are subjected to opposite distortion processing. The combination of the two nonlinear distortion functions can realize a highly linear and distortion-free system. Predistortion processing performed on the analog baseband is called analog predistortion, and predistortion processing performed on the analog circuit is also called analog predistortion. As Figure 1 shown, the predistorter of the analog predistortion system processes the nonlinearity of the PA (i.e., power amplifier) in the analog domain. By generating a curve symmetrical to the PA curve through the predistorter (such as the analog predistortion chip in the following text), and then superimposing it with the PA curve, the linearity of the PA curve after output can be made better, canceling out the nonlinearity, as Figure 1 shown by the curve on the right side of the equal sign in the figure.

[0050] As Figure 2 shown is the circuit structure diagram of a common analog predistortion line system in the conventional analog predistortion linearization technology. The working principle is as follows: The input RF signal is power-controlled through the attenuation circuit ATT and the low-power amplifier tube A, and then a part of the RF signal is coupled through the coupler OC1 and sent to the analog predistortion chip through the balun B1. The RF signal that continues to be transmitted forward through the coupler OC1 is delayed by the delay line L and then combined with the analog predistortion component (i.e., predistortion signal) output by the analog predistortion chip through the balun B2 in the coupler OC2. In this way, the RF signal output from the coupler OC2 to the RF power amplifier PA contains the input RF signal and the predistortion signal. The RF power amplifier PA amplifies the RF signal output from the coupler OC2 and then outputs it to the coupler OC3. The coupler OC3 couples a part of the RF signal as a feedback signal and sends it to the analog predistortion chip through the balun B3, and the RF signal output from the output port of the coupler OC3 is then output externally through the isolator M. The analog predistortion chip automatically generates the corresponding predistortion signal by comparing the difference between the input RF signal and the feedback signal, and outputs the predistortion signal through the balun B2 to the coupler OC2 to be combined with the input RF signal. Through continuous cyclic correction in this way, the linearity of the RF power amplifier PA is finally improved, so that the linearity index of the RF power amplifier is enhanced.

[0051] For existing analog predistortion systems, which have a certain operating bandwidth (i.e., cancellation bandwidth), the inventors found in the practice process that whether the bandwidth of the signal is too wide or too narrow has an impact on the cancellation ability of the analog predistortion system. If the bandwidth of a signal is too narrow, such as the currently used NB-loT (Narrow Band Internet of Things) signal with a bandwidth of only 180 kHz, the cancellation ability of the traditional analog predistortion system for such a narrowband signal will be very poor. Based on this, the present application will provide the following technical solutions to solve this problem:

[0052] Please refer to Figure 3 , in one embodiment, an analog predistortion processing circuit 100 is provided, including a narrowband spreading module 12, an analog predistortion module 14, and a filtering module 16. The narrowband spreading module 12 is configured to spread the input narrowband radio frequency signal into a broadband radio frequency signal. The bandwidth of the broadband radio frequency signal is a preset bandwidth. The analog predistortion module 14 is configured to perform analog predistortion linearization processing on the broadband radio frequency signal to obtain a linearized broadband radio frequency signal. The preset bandwidth is within the optimal cancellation bandwidth of the analog predistortion module 14. The filtering module 16 is configured to perform signal filtering on the linearized broadband radio frequency signal to obtain a linearized narrowband radio frequency signal.

[0053] It can be understood that the narrowband spreading module 12 can be a circuit module or device in the art with a signal bandwidth expansion function, such as a mixer, a combiner, or a combined circuit thereof, etc., and can expand the bandwidth of the input signal to the required bandwidth according to the set signal bandwidth size. The analog predistortion module 14 is a conventional analog predistortion device (chip system) in the art. The specific circuit structures of different models of the analog predistortion module 14 will be different, and can provide different performance predistortion linearization processing functions. The specific structure of the analog predistortion module 14 can be determined by the specific circuit structure of the analog predistortion device selected according to the application index requirements in actual applications. The filtering module 16 is a filter or a filter circuit module whose filtering bandwidth corresponds to the spreading bandwidth of the narrowband spreading module 12, such as, but not limited to, a single or multiple filters, or a comprehensive filter circuit module with a filtering and amplification function after filtering.

[0054] Specifically, different analog predistortion modules 14 have different optimal cancellation bandwidths. If the bandwidth of the input radio frequency signal is within the optimal cancellation bandwidth of the analog predistortion module 14, the analog predistortion module 14 has better cancellation performance for the radio frequency signal. In actual applications, there will be occasions where the bandwidth of the input radio frequency signal is extremely narrow. Therefore, in the application scenarios where the received input signal is a narrowband radio frequency signal, the spreading parameters of the narrowband spreading module 12 can be set in advance according to the bandwidth of the narrowband radio frequency signal. For example, the bandwidth of the signal that is autonomously generated in the narrowband spreading module 12 or received from an external signal source and used for spreading, so as to spread the input narrowband radio frequency signal to a broadband radio frequency signal with a preset bandwidth.

[0055] In actual applications, a signal bandwidth detection device can also be set at the input end of the narrowband spreading module 12 to automatically detect the bandwidth of the input radio frequency signal, and report the detected bandwidth to the main controller of the device to which the analog predistortion processing circuit 100 is applied. The main controller determines whether the currently input radio frequency signal is a broadband radio frequency signal or a narrowband radio frequency signal. If it is a broadband radio frequency signal (that is, a radio frequency signal whose signal bandwidth is already within the optimal cancellation bandwidth of the analog predistortion module 14), the main controller does not need to control the narrowband radio frequency signal. The broadband radio frequency signal does not pass through the narrowband spreading module 12, but directly enters the analog predistortion module 14 for predistortion processing and then is output externally. The external output here can be directly output without passing through the filtering module 16, or can be output externally after passing through the filtering module 16. If it is a narrowband radio frequency signal, the main controller can adjust the spreading parameters of the narrowband spreading module 12 according to the preset spreading parameter table, so as to spread the input narrowband radio frequency signal to a broadband radio frequency signal with a preset bandwidth. The spreading parameter table pre-stores the spreading bandwidth sizes required for spreading narrowband radio frequency signals with different bandwidths. After receiving the control signal output by the main controller, the narrowband spreading module 12 can spread the narrowband radio frequency signal according to the spreading bandwidth size.

[0056] The broadband radio frequency signal obtained after spreading by the narrowband spreading module 12 enters the analog predistortion module 14, and the analog predistortion module 14 completes the analog predistortion linearization processing, so as to obtain a linearized broadband radio frequency signal for output. Thereafter, the linearized broadband radio frequency signal enters the filtering module 16 for filtering processing to filter out the spreading components in the linearized broadband radio frequency signal, that is, the signal components superimposed on the narrowband radio frequency signal when the narrowband spreading module 12 spreads the input narrowband radio frequency signal. After the linearized broadband radio frequency signal is filtered by the filtering module 16, the output is the narrowband radio frequency signal that has been effectively subjected to analog predistortion linearization processing.

[0057] By adopting the narrowband spread spectrum module 12 and the filtering module 16 and performing circuit optimization design with the analog predistortion module 14, when the input radio frequency signal is a narrowband radio frequency signal, the narrowband radio frequency signal can be spread spectrum to expand the narrowband radio frequency signal to a broadband radio frequency signal with a bandwidth within the optimal cancellation bandwidth of the analog predistortion module 14. Furthermore, the analog predistortion module 14 can normally and effectively perform analog predistortion linearization processing on the broadband radio frequency signal. Finally, by filtering the broadband radio frequency signal after the analog predistortion linearization processing to remove the spread spectrum component in the broadband radio frequency signal, the linearized narrowband radio frequency signal can be obtained, realizing the analog predistortion linearization processing of the narrowband radio frequency signal, greatly improving the analog predistortion system, that is, the analog predistortion processing circuit 100 improved based on the analog predistortion module 14, and the cancellation ability for the narrowband radio frequency signal.

[0058] Please refer to Figure 4 , in one embodiment, the narrowband spread spectrum module 12 includes a combiner 122 and a spread spectrum signal source 124. The first input port of the combiner 122 is used to receive the narrowband radio frequency signal. The second input port of the combiner 122 is connected to the output end of the spread spectrum signal source 124. The spread spectrum signal source 124 is used to output a broadband signal with a target bandwidth to the combiner 122 after receiving the indication signal output by the main controller of the predistortion system. The combiner 122 is used to combine the broadband signal and the narrowband radio frequency signal and output the obtained broadband radio frequency signal to the analog predistortion module 14.

[0059] It can be understood that the spread spectrum signal source 124 is a conventional signal source in the art, and can control the signal according to a preset signal bandwidth or a signal bandwidth received in real time from the main controller to generate a signal with a corresponding bandwidth. The target bandwidth refers to the signal bandwidth required to expand the bandwidth of the input narrowband radio frequency signal to a preset bandwidth. The bandwidth of the signal generated by the spread spectrum signal source 124 can be manually preset as the target bandwidth by a person according to the bandwidth of the narrowband radio frequency signal input in the actual application scenario and its spread spectrum requirement, or can be automatically set for the spread spectrum signal source 124 by the main controller according to a preset spread spectrum parameter table, and the target bandwidth with different bandwidth sizes can be automatically changed according to the need in real time. The main controller of the predistortion system also refers to the main controller in the device to which the analog predistortion processing circuit 100 is applied, which provides a control function for the analog predistortion process, and is usually the main control chip inherent in the applied device.

[0060] Specifically, in this embodiment, a combiner 122 and a spread spectrum signal source 124 are used to perform spread spectrum processing on the input narrowband RF signal. The input narrowband RF signal enters the combiner 122 through the first input port of the combiner 122. At the same time, the spread spectrum signal source 124 generates a broadband signal with a target bandwidth and outputs it to the combiner 122 through the second input port of the combiner 122. The combiner 122 combines the input narrowband RF signal and the broadband signal with the target bandwidth to spread the input narrowband RF signal into a broadband RF signal with a preset bandwidth. To more intuitively understand the foregoing spread spectrum process, taking an input narrowband RF signal with a frequency point of 1842.5 MHz and a bandwidth of 160 kHz as an example, the bandwidth of the broadband signal X1 generated by the spread spectrum signal source 124 is 2 MHz, and the center frequency point is 1844.5 MHz. After the input narrowband RF signal Pin and the broadband signal X1 generated by the spread spectrum signal source 124 are combined in the combiner 122, it becomes a broadband signal (Pin + X1) with a preset bandwidth, and then is output to the analog predistortion module 14 for analog predistortion linearization processing. Finally, the broadband signal (Pin + X1) after the analog predistortion linearization processing is filtered by the filter module 16 to filter out the broadband signal X1 in the signal, and the obtained is the narrowband RF signal Pin after the analog predistortion linearization processing. In this way, linearization of the input narrowband RF signal Pin can be achieved within the optimal cancellation bandwidth of the analog predistortion module 14. The preset bandwidth of the broadband RF signal can be less than or equal to the optimal cancellation bandwidth of the analog predistortion module 14, and the cancellation effect can reach the best when they are equal.

[0061] Through the application of the above-mentioned combiner 122 and spread spectrum signal source 124, the spread spectrum processing of the input narrowband RF signal can be realized efficiently and simply, without using relatively complex spread spectrum technologies in this field to realize the spread spectrum processing of the input narrowband RF signal, and the circuit structure is simple and the efficiency is higher.

[0062] Please refer to Figure 5 , in one embodiment, the narrowband spread spectrum module 12 further includes a first coupler 126, a power detector 128, and a first power attenuator 129. The input port of the first coupler 126 is used to receive the narrowband RF signal. The output port of the first coupler 126 is connected to the first input port of the combiner 122. The coupling port of the first coupler 126 is connected to the input port of the power detector 128. The input end of the first power attenuator 129 is connected to the output end of the spread spectrum signal source 124. The output end of the first power attenuator 129 is connected to the second input port of the combiner 122. The power detector 128 is used to detect the signal power of the narrowband RF signal and transmit it to the main controller. The first power attenuator 129 is used to attenuate the signal power of the passed broadband signal to be less than the signal power of the narrowband RF signal after receiving the power adjustment signal output by the main controller.

[0063] It can be understood that the above-mentioned first coupler 126, power detector 128, and first power attenuator 129 are all conventional signal processing devices in the art. The specific types and models of each device can be selected according to the needs of the spread spectrum processing of the input narrowband RF signal and the application cost in the actual application scenario.

[0064] Specifically, since the broadband signal superimposed on the target bandwidth of the input narrowband RF signal needs to be filtered out after being processed and output by the analog pre-distortion module 14, and the power of the broadband signal of the target bandwidth is greater than the signal power of the input narrowband RF signal, it will cause the signal power of the obtained broadband RF signal to be too large, resulting in an increase in the operating current of the analog pre-distortion module 14 and a corresponding increase in energy consumption. Moreover, the input narrowband RF signal becomes a secondary signal relative to the broadband signal of the target bandwidth, and the processing effect of the analog pre-distortion module 14 on the narrowband RF signal component will also decrease. Therefore, it is necessary to control the power of the broadband signal of the target bandwidth to be less than the signal power of the input narrowband RF signal. In some practical application scenarios, when the power of the broadband signal is about 3 dB less than the signal power of the input narrowband RF signal, it can preferably avoid the increase in the operating current of the analog pre-distortion module 14, and the processing effect of the analog pre-distortion module 14 on the narrowband RF signal component is not affected by the power magnitude.

[0065] The input narrowband RF signal enters the combiner 122 through the first coupler 126. At the same time, a part of the input narrowband RF signal is coupled out to the power detector 128 on the first coupler 126. The power detector 128 can obtain the signal power of the input narrowband RF signal and transmit it to the main controller, so that the main controller can control the attenuation amount of the broadband signal output by the spread spectrum signal source 124 by the first power attenuator 129 according to the signal power magnitude of the input narrowband RF signal, so that the signal power of the broadband signal is less than the signal power of the input narrowband RF signal. For example, if the signal power of the input narrowband RF signal is 0 dB, then the first power attenuator 129 attenuates the signal power of the broadband signal output by the spread spectrum signal source 124 to -3 dB, and then the combination of these two signals is output in the combiner 122. In this way, through the application of the above-mentioned first coupler 126, power detector 128, and first power attenuator 129, the signal power of the combined output broadband RF signal is appropriate, which can effectively reduce the energy consumption of the analog pre-distortion module 14 and further improve the analog pre-distortion processing effect.

[0066] Please refer to Figure 6, in one embodiment, the narrowband spread spectrum module 12 further includes a first RF switch 127 and a second RF switch 125. The moving contact of the first RF switch 127 is used to access the narrowband RF signal. The first stationary contact of the first RF switch 127 is connected to the input port of the first coupler 126. The second stationary contact of the first RF switch 127 is connected to the first stationary contact of the second RF switch 125. The second stationary contact of the second RF switch 125 is connected to the combining port of the combiner 122. The moving contact of the second RF switch 125 is connected to the input port of the analog predistortion module 14.

[0067] It can be understood that in this embodiment, two RF switches can be used to select and switch the signal transmission path. The input RF signal enters the analog predistortion processing circuit 100 through the first RF switch 127. If the input RF signal is a broadband RF signal, that is, the analog predistortion processing circuit 100 operates in the ordinary analog predistortion processing mode, the input RF signal can directly enter the analog predistortion module 14 for processing and output without going through the spread spectrum processing. If the input RF signal is a narrowband RF signal, that is, the analog predistortion processing circuit 100 operates in the narrowband cancellation mode, the input RF signal needs to go through the spread spectrum processing before it can enter the analog predistortion module 14 for processing and output.

[0068] Specifically, in the ordinary analog predistortion processing mode, the moving contact and the second stationary contact of the first RF switch 127 are closed, and the moving contact and the first stationary contact of the second RF switch 125 are closed, so as to form a signal direct-through path that does not pass through the first coupler 126 to the combiner 122. The input RF signal directly enters the analog predistortion module 14 through the first RF switch 127 and the second RF switch 125 for the conventional analog predistortion linearization processing in the art.

[0069] Taking the circuit structure of the analog predistortion module 14 adopting the circuit structure of the analog predistortion line system as shown in Figure 2 as an example, after the input RF signal passes through the first RF switch 127 and the second RF switch 125, the signal power is amplified to an appropriate value through the attenuation circuit ATT and the low-power amplifier tube A for power control, and then a part of the RF signal is coupled into the balun B1 through the coupler OC1. The balun B1 converts the input RF signal into IQ signal components (that is, decomposes the input RF signal into two components with the same frequency, the same peak amplitude but a phase difference of 90 degrees, the I component and the Q component). The balun B1 sends the IQ signal components into the analog predistortion chip as the reference signal with the optimal linear effect.

[0070] The radio frequency signal that continues to be transmitted forward through the coupler OC1 is delayed by the delay line L and then combined with the predistortion signal output by the analog predistortion chip through the balun B2 in the coupler OC2. In this way, the radio frequency signal output from the coupler OC2 to the radio frequency power amplifier PA contains the input radio frequency signal and the predistortion signal. The radio frequency power amplifier PA amplifies the signal power of the radio frequency signal output from the coupler OC2 to the required power value and then outputs it to the coupler OC3. The coupler OC3 couples a part of the radio frequency signal as a feedback signal through the balun B3. The balun B3 converts the feedback signal from the radio frequency signal into IQ signal components and sends them into the analog predistortion chip as the feedback reference signal. After comparing the difference between the IQ signal components of the input radio frequency signal and the feedback signal, the analog predistortion chip outputs the corrected IQ signal components. The corrected IQ signal components contain the signal difference between the input radio frequency signal and the feedback signal. The corrected IQ signal components are combined into an analog predistortion signal (also called an analog predistortion correction signal) in the balun B2 and output to the coupler OC2. After being combined with the input radio frequency signal in the coupler OC2, they are sent into the radio frequency power amplifier PA, and the distortion components can be cancelled out. The predistorted radio frequency signal output from the radio frequency power amplifier PA can also couple a part of the radio frequency signal as a feedback signal through the coupler OC3 and send it into the analog predistortion chip through the balun B3 for predistortion processing again. In this way, through continuous loop feedback, the predistortion signal is continuously adjusted automatically, and finally the state with the smallest difference between the feedback signal and the input radio frequency signal is achieved. After analog predistortion, the linearity of the signal output by the radio frequency power amplifier PA can be effectively improved, achieving a linearization effect. Finally, the predistorted radio frequency signal output forward through the coupler OC3 is output through the isolator M.

[0071] In the narrowband cancellation mode, the moving contact and the first stationary contact of the first radio frequency switch 127 are closed, and the moving contact and the second stationary contact of the second radio frequency switch 125 are closed, forming a signal spreading path from the first coupler 126 to the combiner 122. The input radio frequency signal enters the combiner 122 after passing through the first radio frequency switch 127 and the first coupler 126. At the same time, the first coupler 126 couples out a part of the input radio frequency signal to the power detector 128. The power detector 128 can obtain the signal power of the input narrowband radio frequency signal and transmit it to the main controller, so that the main controller can control the attenuation amount of the broadband signal output by the spread spectrum signal source 124 by the first power attenuator 129, so that the signal power of the broadband signal is less than the signal power of the input narrowband radio frequency signal. Then, the combination output of the input radio frequency signal and the broadband signal is completed in the combiner 122. The output broadband radio frequency signal enters the analog predistortion module 14 through the second radio frequency switch 125 for the aforementioned analog predistortion linearization processing.

[0072] The closing action between the contacts of the first RF switch 127 and the second RF switch 125 can be realized by manual toggling, or can be automatically controlled by the main controller according to the preset working mode (that is, the ordinary analog pre-distortion processing mode or the narrowband cancellation mode) through the preset switch control logic. Through the above-mentioned setting of the first RF switch 127 and the second RF switch 125, the switching of the signal paths corresponding to the input RF signals of different bandwidths can be quickly realized, so as to respectively realize the analog pre-distortion processing of the input broadband RF signal or the narrowband RF signal.

[0073] In one embodiment, the filter module 16 is a filter, the input port of the filter is connected to the output port of the analog predistortion module 14, and the output port of the filter is used to output the linearized narrowband RF signal to the outside.

[0074] It can be understood that in this embodiment, a single filter can be directly used to implement filtering processing of the broadband RF signal output by the analog predistortion module 14. The working bandwidth of the filter can be determined according to the signal frequency to be filtered out, that is, it can be determined by the bandwidth of the broadband signal superimposed on the input narrowband RF signal, so as to ensure that the narrowband RF signal component in the broadband RF signal output by the analog predistortion module 14 passes through, while the broadband signal component is filtered out.

[0075] By applying the above filter, the circuit structure is simple and a better filtering effect can be achieved, which is beneficial to reducing the production cost of the analog pre-distortion processing circuit 100.

[0076] See also Figure 7 In one embodiment, the analog predistortion processing circuit 100 further includes a third RF switch 18. The moving contact of the third RF switch 18 is connected to the output port of the analog predistortion module 14. The first static contact of the third RF switch 18 is connected to the input port of the filter. The second static contact of the third RF switch 18 is used to output a broadband RF signal that has not been spread spectrum processed and linearized.

[0077] It can be understood that, on the output port side of the analog predistortion module 14, an RF switch can also be connected to the first RF switch 127 and the second RF switch 125, so that the broadband RF signal that does not need to be processed by spread spectrum and then subjected to analog predistortion linearization can be directly output to the outside without passing through a filter. Correspondingly, the broadband RF signal that is processed by spread spectrum and then subjected to analog predistortion linearization is filtered by the third RF switch 18 and then output to the outside.

[0078] To more easily and intuitively understand the above solution, a detailed working process of the analog predistortion processing circuit 100 in an application scenario is provided: The analog predistortion processing circuit 100 is powered on and initialized, and the working mode can be determined and selected manually; if the ordinary analog predistortion processing mode is selected, the moving contact of the first RF switch 127 is closed with the second stationary contact, the moving contact of the second RF switch 125 is closed with the first stationary contact, the moving contact of the third RF switch 18 is closed with the second stationary contact, and the input RF signal enters the analog predistortion module 14 for analog predistortion linearization processing and is directly output externally through the second stationary contact of the third RF switch 18.

[0079] If the narrowband cancellation mode is selected, the moving contact of the first RF switch 127 is closed with the first stationary contact, the moving contact of the second RF switch 125 is closed with the second stationary contact, the moving contact of the third RF switch 18 is closed with the first stationary contact, the main controller reads the signal power detected by the power detector 128, controls the broadband signal output by the spread spectrum signal source 124, and adjusts the attenuation amount of the first power attenuator 129 according to the signal power detected by the power detector 128, so that the signal power of the broadband signal is less than the signal power of the input narrowband RF signal. After combining, the corresponding broadband RF signal is obtained and sent to the analog predistortion module 14 for analog predistortion linearization processing. Finally, the linearized broadband RF signal passes through the first stationary contact of the third RF switch 18, enters the filter for filtering and then is output externally.

[0080] By applying the above third RF switch 18, the filtering of the RF signal on the output side can be better controlled, and the signal transmission efficiency of the analog predistortion processing circuit 100 can be improved.

[0081] Please refer to Figure 8, in one embodiment, the analog predistortion module 14 includes a power conversion circuit 141, a second coupler 142, a delay line 143, a third coupler 144, a radio frequency power amplifier 145, a fourth coupler 146, an isolator 147, a first balun 148, an analog predistortion chip 149, a second balun 150, and a third balun 151. The power conversion circuit 141, the second coupler 142, the delay line 143, the third coupler 144, the radio frequency power amplifier 145, the fourth coupler 146, and the isolator 147 are connected in series in sequence. The input port of the power conversion circuit 141 is connected to the output port of the narrowband spread spectrum module 12. The output port of the isolator 147 is connected to the input port of the filtering module 16. The coupling port of the second coupler 142 is connected to the input port of the analog predistortion chip 149 through the first balun 148. The output port of the analog predistortion chip 149 is connected to the coupling port of the third coupler 144 through the second balun 150. The coupling port of the fourth coupler 146 is connected to the feedback input port of the analog predistortion chip 149 through the third balun 151.

[0082] It can be understood that the power conversion circuit 141 can be a circuit module or an integrated chip in the field that has the signal power regulation function of analog signals, and can be specifically selected according to the size of the input radio frequency signal power, the output power requirement, etc. The second coupler 142, the delay line 143, the third coupler 144, the radio frequency power amplifier 145, the fourth coupler 146, the isolator 147, and devices such as the first balun 148, the analog predistortion chip 149, the second balun 150, and the third balun 151 can all be traditional conventional devices in the field, for example Figure 2 the corresponding devices shown in, and the specific models can be selected correspondingly according to the characteristics of the transmitted signal in the actual application scenario.

[0083] Specifically, the broadband radio frequency signal input to the analog predistortion module 14 can be the broadband radio frequency signal corresponding to the output after the narrowband radio frequency signal is input and spread spectrum processed by the narrowband spread spectrum module 12, or the broadband radio frequency signal that is normally input and does not require spread spectrum processing. The input broadband radio frequency signal first undergoes signal power control by the power conversion circuit 141 to amplify the signal power to an appropriate value, and then a part of the radio frequency signal is coupled through the second coupler 142 and sent to the first balun 148. The first balun 148 converts the input broadband radio frequency signal into IQ signal components and then sends them to the analog predistortion chip 149 as the reference signal with the optimal linear effect.

[0084] The broadband RF signal that continues to be transmitted forward through the second coupler 142 is delayed by the delay line 143 and then combined with the predistortion signal output by the analog predistortion chip 149 through the second balun 150 in the third coupler 144. Thus, the RF signal output from the third coupler 144 to the RF power amplifier 145 contains the input broadband RF signal and the predistortion signal. After amplifying the signal power of the broadband RF signal output from the third coupler 144 to the required power value, the RF power amplifier 145 outputs it to the fourth coupler 146. The fourth coupler 146 couples a part of the RF signal as a feedback signal. The feedback signal is converted from the broadband RF signal into the corresponding IQ signal components through the third balun 151 and sent to the analog predistortion chip 149 as a feedback reference signal. After comparing the difference between the IQ signal components of the input broadband RF signal and the feedback signal, the analog predistortion chip 149 outputs the corrected IQ signal components.

[0085] The corrected IQ signal components contain the signal difference between the input broadband RF signal and the feedback signal. The corrected IQ signal components are combined into an analog predistortion signal (also called an analog predistortion correction signal) in the second balun 150 and output to the third coupler 144. After being combined with the input broadband RF signal in the third coupler 144, it is sent to the RF power amplifier 145, where the distortion components can be cancelled out. The predistorted broadband RF signal output from the RF power amplifier 145 can again couple a part of the RF signal as a new feedback signal through the fourth coupler 146 and send it to the analog predistortion chip 149 through the third balun 151 for predistortion processing again. In this way, through continuous loop feedback, the predistortion signal is continuously adjusted automatically, and finally reaches a state where the difference between the feedback signal and the input RF signal is minimized. After analog predistortion, the linearity of the signal output from the RF power amplifier 145 can be effectively improved, achieving a linearization effect. Finally, the predistorted broadband RF signal output forward through the fourth coupler 146 is output through the isolator 147.

[0086] If the broadband RF signal input to the analog predistortion module 14 is a narrowband RF signal input and output as a broadband RF signal after being spread spectrum by the narrowband spread spectrum module 12, the broadband RF signal output by the isolator 147 enters the filter through the first stationary contact of the third RF switch 18 for filtering to filter out the spread spectrum signal (i.e., the broadband signal of the target bandwidth) superimposed during spread spectrum. The remaining narrowband RF signal is the narrowband RF signal after analog predistortion linearization for external output. If the input broadband RF signal is a broadband RF signal that is normally input and does not require spread spectrum processing, the broadband RF signal output by the RF power amplifier 145, that is, the broadband RF signal that has not been spread spectrum processed and linearized, can be directly output externally through the second stationary contact of the third RF switch 18. By applying the above analog predistortion module 14 for analog predistortion processing of signals, the application cost is not high and the applicability is relatively high.

[0087] Please refer to Figure 9 , in an embodiment, the power conversion circuit 141 includes a second power attenuator 1411 and a low-power amplifier transistor 1412. The second power attenuator 1411 and the low-power amplifier transistor 1412 are connected in series. The input port of the second power attenuator 1411 is connected to the output port of the narrowband spread spectrum module 12, and the output port of the low-power amplifier transistor 1412 is connected to the input port of the second coupler 142.

[0088] It can be understood that in this embodiment, the second power attenuator 1411 is also Figure 2 the attenuation circuit ATT shown in Figure 2 or a power attenuator of the same type but different models. Similarly, the low-power amplifier transistor 1412 is also

[0089] Specifically, the broadband RF signal output by the second RF switch 125 of the narrowband spread spectrum module 12 can be a broadband RF signal obtained by inputting a narrowband RF signal and spreading it through the narrowband spread spectrum module 12, or a broadband RF signal that is normally input and does not require spreading processing. Specifically, it is determined by the input RF signal and the signal transmission path selected by the first RF switch 127 and the second RF switch 125. The broadband RF signal output by the second RF switch 125 is successively subjected to signal power control by the second power attenuator 1411 and the low-power amplifier tube 1412, and then a broadband RF signal with an appropriate power level (which can be determined by the working parameter requirements of the analog predistortion module 14) is output to the second coupler 142 for subsequent processing. By applying the above-mentioned second power attenuator 1411 and low-power amplifier tube 1412 for signal power control of the broadband RF signal, the application cost of analog predistortion can be further reduced and the applicability can be improved.

[0090] In one embodiment, a signal processing device is provided, including the above-mentioned analog predistortion processing circuit 100.

[0091] It can be understood that for the specific limitations of the analog predistortion processing circuit 100 in this embodiment, reference can be made to the limitations of the corresponding embodiments of the analog predistortion processing circuit 100 in the foregoing text, which will not be elaborated here. The signal processing device can be various signal transmission and processing devices in the field that use analog predistortion technology and need to improve the narrowband cancellation performance of analog predistortion. Those skilled in the art can understand that different types of signal processing devices, in addition to including the above-mentioned analog predistortion processing circuit 100, may also include other components, such as a device main control board, a power supply, a chassis, an antenna, and components with other functions, etc. Specifically, it can be determined according to the inherent structure of the specific signal processing device to which the analog predistortion processing circuit 100 is applied.

[0092] By applying the above-mentioned analog predistortion processing circuit 100, when the input RF signal is a narrowband RF signal, the narrowband RF signal can be spread to a broadband RF signal with a bandwidth within the optimal cancellation bandwidth of the analog predistortion module 14. Furthermore, the analog predistortion module 14 can effectively perform analog predistortion linearization processing on the broadband RF signal. Finally, by filtering the broadband RF signal after analog predistortion linearization processing to remove the spread spectrum component in the broadband RF signal, a linearized narrowband RF signal can be obtained, realizing the analog predistortion linearization processing of the narrowband RF signal, and greatly improving the cancellation ability of the analog predistortion system for narrowband RF signals.

[0093] Please refer to Figure 10In one embodiment, the signal processing device further includes a main controller 201. The narrowband spread spectrum module 12 of the analog predistortion processing circuit 100 includes a spread spectrum signal source 124, a power detector 128 and a first power attenuator 129. The main controller 201 is used to output an indication signal to the spread spectrum signal source 124, and to receive the signal power transmitted by the power detector 128, and output a power adjustment signal to the first power attenuator 129.

[0094] Among them, the main controller 201 is an existing controller on the signal processing device, which can automatically control the entire analog predistortion processing process according to the preset analog predistortion processing mode, such as the selection of the mode (non-spread spectrum mode under normal broadband RF signal input, or spread spectrum mode under narrowband RF signal input), and complete the gating switching of the corresponding RF switch, the triggering of the broadband signal generation of the spread spectrum signal source 124, the indication of the attenuation power size of the first power attenuator 129, and the predistortion process regulation of the analog predistortion chip 149, etc. The main controller 201 can be an MCU, a CPU, or a programmable logic device commonly used in the art.

[0095] It can be understood that in the above embodiment, the switching of each RF switch, the triggering of the broadband signal generated by the spread spectrum signal source 124, and the setting of the attenuation power of the first power attenuator 129 can be manually set in advance, or can be automatically completed by an external independent controller (just pre-set it in the independent controller in the manner of manual setting through the general instruction method in the field). However, in this embodiment, the control end of each RF switch, the control end of the spread spectrum signal source 124, the output end of the power detector 128, the control end of the first power attenuator 129, and the control port of the analog pre-distortion chip 149 can be directly connected to the main controller 201 of the signal processing device, and the main controller 201 can automatically complete the control of the entire analog pre-distortion processing process according to the pre-setting.

[0096] Through the main controller 201 thereon, the output indication of the spread spectrum signal source 124 can be automatically realized, so that when the spread spectrum signal source 124 needs to generate a broadband signal with a target bandwidth, it can quickly output the broadband signal with the target bandwidth to the combiner 122 to complete the combined spread spectrum processing of the input narrowband RF signal. At the same time, the main controller 201 can also automatically control the power attenuation of the broadband signal with the target bandwidth by the first power attenuator 129 according to the signal power transmitted by the power detector 128, so as to ensure that the signal power of the broadband signal with the target bandwidth is less than the input narrowband RF signal, so as to limit the signal power of the corresponding output broadband RF signal after combined spread spectrum, reduce the working current in the subsequent analog pre-distortion processing link, and thus effectively save the energy of the entire device. In this way, through the access and application of the main controller 201, the performance of the analog pre-distortion processing can be better improved.

[0097] In one embodiment, as Figure 10 shown, the analog pre-distortion processing circuit 100 further includes a third RF switch 18. The narrowband spread spectrum module 12 further includes a first RF switch 127 and a second RF switch 125. The main controller 201 is electrically connected to the switch control terminals of the first RF switch 127 and the second RF switch 125, and the switch control terminal of the third RF switch 18 respectively. The main controller 201 is further configured to output switch control signals to the first RF switch 127, the second RF switch 125 and the third RF switch 18 respectively.

[0098] It can be understood that for the explanation of the third RF switch 18, the first RF switch 127 and the second RF switch 125 in this embodiment, reference can be made to the explanation of the third RF switch 18, the first RF switch 127 and the second RF switch 125 in the corresponding embodiment of the above analog pre-distortion processing circuit 100, and no further elaboration will be given in this embodiment.

[0099] Specifically, there are multiple control pins on the main controller 201, and the switch control terminals of the third RF switch 18, the first RF switch 127 and the second RF switch 125 can be directly or indirectly electrically connected to the corresponding control pins on the main controller 201 respectively, so as to receive the switch control signals output by the main controller 201 respectively. After the third RF switch 18, the first RF switch 127 and the second RF switch 125 receive the switch control signals respectively, they switch the closed state between their moving contacts and static contacts, thereby forming corresponding signal paths. Through the above circuit connections between each RF switch and the main controller 201, the control of the gating and switching of each RF switch can be automatically completed, thereby effectively improving the switching efficiency of the analog pre-distortion processing mode of input signals with different bandwidths in the signal processing device.

[0100] In one embodiment, the signal processing device is any one of a baseband amplifier device, a repeater device, a remote radio unit device, a track power amplifier device, an integrated power amplifier, and a receiver.

[0101] It can be understood that the signal processing device applying the above analog pre-distortion processing circuit 100 can be any one of a baseband amplifier device (i.e., a power amplifier device in a base station of a communication system), a repeater device, a remote radio unit device, a track power amplifier device, an integrated power amplifier (i.e., an integrated power amplifier device formed by integrating a radio frequency power amplifier device and other power amplifier-related components on the same structural base), and a receiver, so as to improve the analog pre-distortion narrowband cancellation performance of the device. Those skilled in the art can understand that the foregoing are only several of the signal processing devices, and the above analog pre-distortion processing circuit 100 can also be applied to other devices that need to improve the analog pre-distortion narrowband cancellation performance.

[0102] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0103] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A simulated pre-distortion processing circuit, characterized in that, it includes: A narrowband spread-spectrum module, configured to spread-spectrum an input narrowband radio frequency signal into a broadband radio frequency signal; The bandwidth of the broadband radio frequency signal is a preset bandwidth; A simulated pre-distortion module, configured to perform simulated pre-distortion linearization processing on the broadband radio frequency signal to obtain a linearized broadband radio frequency signal; the preset bandwidth is within the optimal cancellation bandwidth of the simulated pre-distortion module; A filtering module, configured to perform signal filtering on the linearized broadband radio frequency signal to obtain a linearized narrowband radio frequency signal; The narrowband spread-spectrum module includes a combiner and a spread-spectrum signal source. The first input port of the combiner is used to receive the narrowband radio frequency signal, and the second input port of the combiner is connected to the output end of the spread-spectrum signal source; The spread-spectrum signal source is configured to output a broadband signal with a target bandwidth to the combiner after receiving an indication signal output by the main controller of the pre-distortion system. The combiner is configured to combine the broadband signal with the narrowband radio frequency signal and output the obtained broadband radio frequency signal to the simulated pre-distortion module.

2. The simulated pre-distortion processing circuit according to claim 1, characterized in that, The narrowband spread-spectrum module further includes a first coupler, a power detector, and a first power attenuator; The input port of the first coupler is used to receive the narrowband radio frequency signal. The output port of the first coupler is connected to the first input port of the combiner. The coupling port of the first coupler is connected to the input port of the power detector. The input end of the first power attenuator is connected to the output end of the spread-spectrum signal source, and the output end of the first power attenuator is connected to the second input port of the combiner; The power detector is configured to detect the signal power of the narrowband radio frequency signal and transmit it to the main controller. The first power attenuator is configured to attenuate the signal power of the passed broadband signal to be less than the signal power of the narrowband radio frequency signal after receiving a power adjustment signal output by the main controller.

3. The simulated pre-distortion processing circuit according to claim 2, characterized in that, The narrowband spread-spectrum module further includes a first radio frequency switch and a second radio frequency switch; The moving contact of the first radio frequency switch is used to access the narrowband radio frequency signal. The first stationary contact of the first radio frequency switch is connected to the input port of the first coupler. The second stationary contact of the first radio frequency switch is connected to the first stationary contact of the second radio frequency switch; The second stationary contact of the second radio frequency switch is connected to the combining port of the combiner. The moving contact of the second radio frequency switch is connected to the input port of the simulated pre-distortion module.

4. The simulated pre-distortion processing circuit according to any one of claims 1 to 3, characterized in that, The filtering module is a filter. The input port of the filter is connected to the output port of the simulated pre-distortion module, and the output port of the filter is used to externally output the linearized narrowband radio frequency signal.

5. The simulated pre-distortion processing circuit according to claim 4, characterized in that, It further includes a third RF switch. The moving contact of the third RF switch is connected to the output port of the analog predistortion module. The first stationary contact of the third RF switch is connected to the input port of the filter. The second stationary contact of the third RF switch is used to output externally the broadband RF signal that has not undergone spread spectrum processing and is linearized.

6. The analog predistortion processing circuit according to claim 1, wherein, the analog predistortion module includes a power conversion circuit, a second coupler, a delay line, a third coupler, a RF power amplifier, a fourth coupler, an isolator, a first balun, an analog predistortion chip, a second balun and a third balun; the power conversion circuit, the second coupler, the delay line, the third coupler, the RF power amplifier, the fourth coupler and the isolator are connected in series in sequence. The input port of the power conversion circuit is connected to the output port of the narrowband spread spectrum module. The output port of the isolator is connected to the input port of the filter module; the coupling port of the second coupler is connected to the input port of the analog predistortion chip through the first balun. The output port of the analog predistortion chip is connected to the coupling port of the third coupler through the second balun; the coupling port of the fourth coupler is connected to the feedback input port of the analog predistortion chip through the third balun.

7. The analog predistortion processing circuit according to claim 6, wherein, the power conversion circuit includes a second power attenuator and a low-power amplifier tube; the second power attenuator and the low-power amplifier tube are connected in series. The input port of the second power attenuator is connected to the output port of the narrowband spread spectrum module. The output port of the low-power amplifier tube is connected to the input port of the second coupler.

8. A signal processing device, wherein, it includes the analog predistortion processing circuit according to claim 1.

9. The signal processing device according to claim 8, wherein, it further includes a main controller. The narrowband spread spectrum module of the analog predistortion processing circuit includes a spread spectrum signal source, a power detector and a first power attenuator; the main controller is used to output an indication signal to the spread spectrum signal source, and is used to receive the signal power transmitted by the power detector and output a power adjustment signal to the first power attenuator.

10. The signal processing device according to claim 9, wherein, the analog predistortion processing circuit further includes a third RF switch. The narrowband spread spectrum module further includes a first RF switch and a second RF switch; the main controller is electrically connected to the switch control ends of the first RF switch and the second RF switch respectively, and the switch control end of the third RF switch. The main controller is further used to output switch control signals to the first RF switch, the second RF switch and the third RF switch respectively.

11. The signal processing device according to any one of claims 8 to 10, wherein, the signal processing device is any one of a baseband amplifier device, a repeater device, a remote radio unit device, a track power amplifier device, an integrated power amplifier and a receiver.

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