WO2021088848A1 - 带内波动抑制装置和射频系统 - Google Patents

带内波动抑制装置和射频系统 Download PDF

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Publication number
WO2021088848A1
WO2021088848A1 PCT/CN2020/126399 CN2020126399W WO2021088848A1 WO 2021088848 A1 WO2021088848 A1 WO 2021088848A1 CN 2020126399 W CN2020126399 W CN 2020126399W WO 2021088848 A1 WO2021088848 A1 WO 2021088848A1
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Prior art keywords
impedance adjustment
impedance
suppression device
band fluctuation
acoustic wave
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PCT/CN2020/126399
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English (en)
French (fr)
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马超
金淮东
李华鸿
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三维通信股份有限公司
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Publication of WO2021088848A1 publication Critical patent/WO2021088848A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits
    • H04B1/0475—Circuits with means for limiting noise, interference or distortion
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
    • H04B1/12—Neutralising, balancing, or compensation arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/155—Ground-based stations
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits
    • H04B2001/0408—Circuits with power amplifiers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/02—Transmitters
    • H04B1/04—Circuits
    • H04B2001/0491—Circuits with frequency synthesizers, frequency converters or modulators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • This application relates to the field of communication technology, and in particular to an in-band fluctuation suppression device and a radio frequency system.
  • Repeater is a kind of base station radio frequency remote equipment.
  • the repeater is composed of components or modules such as antenna, radio frequency duplexer, low noise amplifier, mixer, electric attenuator, filter, power amplifier, etc., including uplink and downlink.
  • the basic principle of the repeater is: use the forward antenna to receive the downlink signal of the base station into the repeater, amplify the useful signal through the low-noise amplifier, suppress the noise signal in the signal, and improve the signal-to-noise ratio; and then down-convert to The intermediate frequency signal is filtered by a filter, amplified by the intermediate frequency, and then shifted and upconverted to radio frequency, amplified by the power amplifier, and transmitted from the backward antenna to the mobile station; at the same time, the backward antenna is used to receive the mobile station's uplink signal, and follow the opposite path from the uplink
  • the link performs the same processing as the downlink: that is, it passes through a low-noise amplifier, down-converter, filter
  • Field Programmable Gate Array In repeaters or other remote radio equipment, in-band fluctuations are usually required to be no more than 3dB.
  • Field Programmable Gate Array FPGA for short
  • FPGA Field Programmable Gate Array
  • FIR Finite Impulse Response
  • ADC analog-to-digital converter
  • the FIR filter is added to compensate the in-band fluctuation of the radio frequency system.
  • the principle of the FIR filter to suppress the in-band fluctuation of the radio frequency system is to generate a feedback signal that is opposite to the frequency response of the in-band fluctuation based on the original digital intermediate frequency signal, and use the feedback signal to compensate the digital intermediate frequency signal to offset the in-band fluctuation.
  • using the above-mentioned method to suppress in-band fluctuations will not only lead to the occupation of FPGA resources, but also have relatively high requirements on the operating frequency of the FPGA.
  • an in-band fluctuation suppression device includes: an impedance adjustment module and a surface acoustic wave filter module, the impedance adjustment module being coupled to the surface acoustic wave A filter module, wherein the impedance adjustment module is used to adjust the impedance of the application circuit so that the frequency response characteristic of the surface acoustic wave filter module and the response characteristic of the in-band fluctuation of the application circuit within the working frequency range in contrast.
  • the impedance adjustment module is coupled to the input terminal and/or the output terminal of the surface acoustic wave filter module.
  • the impedance adjustment module includes: a first impedance adjustment module and a second impedance adjustment module, wherein the first impedance adjustment module is coupled to the input end of the surface acoustic wave filter module, so The second impedance adjustment module is coupled to the output end of the surface acoustic wave filter module.
  • the first impedance adjustment module and the second impedance adjustment module have the same circuit topology.
  • the first impedance adjustment module and the second impedance adjustment module have different circuit topologies.
  • the impedance adjustment module includes: one or more impedance adjustment sub-circuits; the connection mode between the multiple impedance adjustment sub-circuits is series and/or parallel.
  • the impedance adjustment sub-circuit includes at least one of the following: an L-type impedance adjustment sub-circuit, a T-type impedance adjustment sub-circuit, and a ⁇ -type impedance adjustment sub-circuit.
  • the configuration mode of the parameters of the impedance adjustment module includes at least one of the following: online debugging configuration and simulation configuration.
  • a radio frequency system including one or more of the in-band fluctuation suppression devices.
  • the radio frequency system includes an uplink and a downlink; wherein the in-band fluctuation suppression device is coupled between two stable impedance circuits of the uplink, and/or The in-band fluctuation suppression device is coupled between the two stable impedance circuits of the downlink.
  • the in-band fluctuation suppression device of the present application uses an impedance adjustment module to adjust the impedance of the application circuit, so that the frequency response characteristics of the surface acoustic wave filter module of the in-band fluctuation suppression device and the application circuit are in the operating frequency range
  • the in-band fluctuation response characteristic of the in-band fluctuates in the opposite manner, which solves the problem of high requirements on the operating frequency of the FPGA due to the use of FPGA to suppress in-band fluctuations in the related technology, and avoids the dependence of the in-band fluctuation suppression device on the operating frequency of the FPGA.
  • Fig. 1 is a structural block diagram of an in-band fluctuation suppression device according to an embodiment of the present application.
  • FIG. 2 is a diagram of the amplitude of the output waveform of the surface acoustic wave filter module in the case where the electrode impedance of the surface acoustic wave filter module matches the impedance of the application circuit according to an embodiment of the present application.
  • FIG. 3 is a diagram showing the amplitude of the output waveform of the surface acoustic wave filter module when the electrode impedance of the surface acoustic wave filter module is mismatched with the impedance of the application circuit according to an embodiment of the present application.
  • FIG. 4 is a phase diagram of the output waveform of the surface acoustic wave filter module when the electrode impedance of the surface acoustic wave filter module matches the impedance of the application circuit according to the embodiment of the present application.
  • FIG. 5 is a phase diagram of the output waveform of the surface acoustic wave filter module when the electrode impedance of the surface acoustic wave filter module is mismatched with the impedance of the application circuit according to an embodiment of the present application.
  • FIG. 6 is a topological diagram 1 of the impedance adjustment sub-circuit of an embodiment of the present application.
  • FIG. 7 is a second topology diagram of the impedance adjustment sub-circuit of an embodiment of the present application.
  • FIG. 8 is the third topology diagram of the impedance adjustment sub-circuit of the embodiment of the present application.
  • FIG. 9 is a topology diagram of the in-band fluctuation suppression device of an embodiment of the present application.
  • Fig. 10 is a structural block diagram of a radio frequency system according to an embodiment of the present application.
  • connection refers to physical or mechanical connections, but may include electrical connections, whether direct or indirect.
  • the "plurality”, “individual”, and “different” referred to in this application refer to two or more.
  • “And/or” describes the association relationship of the associated objects, which means that there can be three kinds of relationships. For example, “A and/or B” can mean: A alone exists, A and B exist at the same time, and B exists alone.
  • the character “/” generally indicates that the associated objects before and after are in an “or” relationship.
  • first”, “second”, “third”, etc. involved in this application merely distinguish similar objects, and do not represent a specific ordering of objects.
  • FIG. 1 is a structural block diagram of an in-band fluctuation suppression device according to an embodiment of the present application.
  • the in-band fluctuation suppression device includes an impedance adjustment module 20 and a surface acoustic wave filter module 10, wherein the impedance adjustment module 20 Coupled to the surface acoustic wave filter module 10.
  • the impedance adjustment module 20 is used to adjust the impedance of the application circuit, so that the response characteristic of the surface acoustic wave filter module 10 is opposite to the response characteristic of the in-band fluctuation of the application circuit in the operating frequency range.
  • the above-mentioned in-band fluctuation suppression device can be connected in series in the radio frequency system of a radio frequency remote unit such as a repeater, an optical fiber remote unit, etc., to suppress the in-band fluctuation of the radio frequency system.
  • a radio frequency remote unit such as a repeater, an optical fiber remote unit, etc.
  • the surface acoustic wave filter module 10 is usually composed of an impedance matching network and a SAW filter.
  • the SAW filter is made of materials with piezoelectric effect such as quartz, lithium niobate, and barium titanate crystal.
  • the SAW filter has an input interdigital transducer and an output interdigital transducer. When the input interdigital transducer is connected to an AC voltage signal, the surface of the piezoelectric crystal substrate vibrates and excites a sound wave with the same frequency as the external signal.
  • This sound wave is mainly along the surface of the substrate and the interdigital electrode Propagation in the rising direction, the sound wave in one direction is absorbed by the sound-absorbing material, and the sound wave in the other direction is transmitted to the output interdigital transducer and converted into electrical signal output.
  • the SAW filter Since the SAW filter performs mutual conversion between the acoustic signal and the electrical signal through the interdigital transducer, the SAW filter has the characteristics of three echoes. That is, in the SAW filter, when the main signal in the form of a surface acoustic wave reaches the output electrode, it is converted into an electrical signal and output by the inverse piezoelectric effect of the output interdigital transducer. However, at this time, the output electrode can also be regarded as an input electrode, so the output interdigital transducer of the output electrode converts a part of the main signal that has been converted into an electrical signal form and converts it into a surface acoustic wave through the piezoelectric effect.
  • the impedance of the application circuit to which the surface acoustic wave filter module is connected will affect the third echo of the SAW filter, which in turn affects the frequency response characteristics of the surface acoustic wave filter module.
  • the following experiments will be used to illustrate the influence of the impedance of the application circuit connected to the surface acoustic wave filter module on the frequency response characteristics of the surface acoustic wave filter module.
  • the standard impedance is usually 50 ohms or 75 ohms, which is usually determined by the impedance of the transmission line in the circuit.
  • impedance matching that is, when the internal resistance of the signal source is equal to the characteristic impedance of the connected transmission line and has the same phase, or the characteristic impedance of the transmission line is equal to the impedance of the connected load and the same phase, the transmission line can obtain the maximum power or the transmission line All the energy carried on it can be absorbed by the load. Therefore, the electrode impedance on the input electrode and output electrode of the surface acoustic wave filter module is usually adjusted to the standard impedance by the matching network.
  • the frequency response characteristic of the surface acoustic wave filter module usually refers to its electrode impedance and the connected application circuit. Frequency response characteristics in the case of impedance matching.
  • the electrode impedance of the tested surface acoustic wave filter module is 50 ohms, and its passband is 1710 ⁇ 1735MHz.
  • the input electrode and the output electrode of the surface acoustic wave filter module are respectively connected in series with impedance adjustment modules to adjust the impedance of the application circuit to match or mismatch with the electrode impedance of the surface acoustic wave filter module.
  • impedance matching and impedance mismatch input a square wave with the same amplitude and phase to the input end of the surface acoustic wave filter module, and use an oscilloscope to observe the amplitude and phase of the output waveform of the surface acoustic wave filter module. Variety.
  • Figure 2 and Figure 3 respectively show the amplitude diagrams of the output waveform of the surface acoustic wave filter module when the electrode impedance of the surface acoustic wave filter module in the pass band of 1710 ⁇ 1735 MHz is matched or mismatched with the impedance of the application circuit.
  • Figures 2 and 3 it can be observed that after the impedance of the application circuit is changed from matching with the electrode impedance to being mismatched with the electrode impedance, the amplitude of the waveform of the surface acoustic wave filter module has changed.
  • Figures 4 and 5 respectively show the phase diagram of the output waveform of the surface acoustic wave filter module when the electrode impedance of the surface acoustic wave filter module matches or mismatches the impedance of the application circuit in the pass band 1710 ⁇ 1735 MHz. . According to Fig. 4 and Fig. 5, it can be observed that the phase of the waveform of the surface acoustic wave filter module has changed after the impedance of the application circuit changes from matching with the electrode impedance to being mismatched with the electrode impedance.
  • the impedance of the application circuit affects the vibration of the interdigital transducer inside the SAW filter, including the influence of the characteristics of the three echoes superimposed, which changes the initial performance of the SAW filter.
  • the response characteristic of the surface acoustic wave filter module is affected by the impedance of the application circuit, and the frequency response characteristic of the surface acoustic wave filter module can be adjusted to be the same as that of the application circuit by adjusting the impedance of the application circuit.
  • the response characteristics of in-band fluctuations in the operating frequency range are opposite.
  • an impedance adjustment module 20 is added to the surface acoustic wave filter module 10 to adjust the impedance of the application circuit, so that the frequency response characteristics of the surface acoustic wave filter module 10 and the application circuit are working.
  • the response characteristics of in-band fluctuations in the frequency range are opposite, so that the three echoes of the SAW filter are superimposed with the initial signal to offset the in-band fluctuations of the initial signal, and realize the in-band fluctuation compensation of the application circuit in the working frequency range.
  • the coordination of the impedance adjustment module 20 and the surface acoustic wave filter module 10 and other analog devices can effectively suppress in-band fluctuations, which solves the problem of high requirements for FPGA operation frequency due to the use of FPGAs to suppress in-band fluctuations in related technologies.
  • the problem also avoids the occupation of FPGA resources.
  • the in-band fluctuation suppression device based on the surface acoustic wave filter module 10 also has the advantages of simple manufacturing process, good passband characteristics, high reliability, high consistency, small size and strong versatility.
  • a surface acoustic wave filter module that is the same as or slightly larger than the passband of the application circuit can be selected to build an in-band ripple suppression device to achieve different passbands. In-band fluctuation compensation of the application circuit of the belt.
  • the impedance adjustment module 20 can be coupled in series to the input end of the surface acoustic wave filter module 10, or can be coupled in series to the output end of the surface acoustic wave filter module 10, or in the surface acoustic wave filter module 10.
  • the input terminal and the output terminal of the impedance adjustment module 20 are respectively coupled.
  • coupling the impedance adjustment module 20 to the input end and the output end of the surface acoustic wave filter module 10 can improve the effect of in-band fluctuation suppression and simplify the configuration difficulty of the impedance adjustment module 20 parameters.
  • the impedance adjustment module 20 in this embodiment may be composed of one or more impedance adjustment sub-circuits.
  • These impedance adjustment sub-circuits include but are not limited to at least one of the following: an L-type impedance adjustment sub-circuit, a T-type impedance adjustment sub-circuit, and a ⁇ -type impedance adjustment sub-circuit.
  • the number of each type of impedance adjustment sub-circuits can be configured as required, and the connection mode between the various impedance adjustment sub-circuits can be series and/or parallel.
  • the L-shaped impedance adjusting sub-circuit is an L-shaped circuit composed of at least two types of elements among resistors, capacitors, and inductors.
  • the L-type impedance adjustment sub-circuit has the advantages of simple circuit and low cost. Based on the consideration of reducing power loss, the L-type impedance adjustment sub-circuit uses inductive and capacitive components as much as possible, and does not use resistors as much as possible. Therefore, the L-type impedance adjustment sub-circuit of this embodiment is preferably one of the eight circuits shown in FIG. 6.
  • the T-type impedance adjustment sub-circuit is a T-type circuit composed of at least two types of elements among resistors, capacitors, and inductors. Based on the consideration of reducing power loss, the T-type impedance adjustment sub-circuit uses inductive and capacitive components as much as possible, and does not use resistors as much as possible. Two preferred T-type impedance adjustment sub-circuits are shown in FIG. 7.
  • the ⁇ -type impedance adjusting sub-circuit is a ⁇ -type circuit composed of at least two types of elements among resistors, capacitors, and inductors. Based on the consideration of reducing power loss, the ⁇ -type impedance adjustment sub-circuit uses inductive and capacitive components as much as possible, and does not use resistors as much as possible. Two preferred ⁇ -type impedance adjustment sub-circuits are shown in FIG. 8.
  • a more preferred solution for the impedance adjustment sub-circuit is to use a capacitor in series with the surface acoustic wave filter module, and an inductance with the surface acoustic wave filter module in parallel, so as to achieve the functions of blocking direct current and providing an electrostatic discharge channel.
  • FIG. 9 is a topological diagram of the in-band ripple suppression device according to a preferred embodiment of the present application.
  • the in-band ripple suppression device includes four inductors, four capacitors, and a surface acoustic wave filter module 10.
  • an L-type impedance adjustment sub-circuit is composed of an inductor and a capacitor, and there are a total of four L-type impedance adjustment sub-circuits.
  • Two of the L-type impedance adjustment sub-circuits are coupled in series and then coupled to the input end of the surface acoustic wave filter module 10, and the other two L-type impedance adjustment sub-circuits are coupled in series and then coupled to the output of the surface acoustic wave filter module 10 end.
  • circuit topology of the impedance adjustment module connected in series with the front end and the back end of the surface acoustic wave filter module 10 shown in FIG. 9 is the same, it is not limited to this in the embodiment of the present application, that is, The circuit topology of the impedance adjustment module connected in series at the front end and the back end of the surface acoustic wave filter module 10 may also be different.
  • the manner of configuring the parameters of the impedance adjustment module includes, but is not limited to: online debugging configuration and/or simulation configuration.
  • the online debugging configuration refers to connecting the impedance adjustment module in series to the application circuit, and then debug each parameter of the impedance adjustment module and detect the fluctuations in the band at the same time, and finally the appropriate impedance adjustment module parameters will be debugged.
  • the simulation configuration is to simulate the application circuit in the computer and test the parameter configuration of various impedance adjustment modules. After obtaining the parameters that can meet the needs, the impedance adjustment module is designed according to the parameters obtained by the simulation simulation, and finally connected The compensation of in-band fluctuation is realized in the actual application circuit.
  • the above parameter configuration methods can also be used together or in conjunction with other parameter configuration methods.
  • the impedance of the application circuit after the impedance is adjusted by the impedance adjustment module and the electrode impedance of the surface acoustic wave filter module may be matched or mismatched.
  • a radio frequency system is also provided.
  • Fig. 10 is a structural block diagram of a radio frequency system according to an embodiment of the present application.
  • the radio frequency system includes one or more in-band fluctuation suppression devices, which are realized by installing in-band fluctuation suppression devices in the radio frequency system. In-band fluctuation compensation for radio frequency systems.
  • the radio frequency system includes uplink and downlink; among them, according to the in-band fluctuation of the uplink and downlink, the in-band can be selectively inserted in the uplink and/or downlink. Fluctuation suppression device to achieve in-band fluctuation compensation.
  • the in-band fluctuation suppression device is inserted between two stable impedance circuits of the uplink or the downlink.
  • the uplink may include: a low noise amplifier (LNA) circuit, an analog-to-digital converter (ADC), a first in-band fluctuation suppression device, and a reverse operation (REV) interface
  • the downlink may include: A power amplifier circuit, a digital-to-analog converter (DAC), a second in-band fluctuation suppression device and a forward running (FWD) interface
  • the coupling relationship in the uplink is preferably: REV interface, LNA circuit, first in-band fluctuation suppression
  • the device and the ADC are coupled in sequence
  • the coupling relationship in the downlink is preferably: the DAC, the second in-band fluctuation suppression device, the power amplifier circuit, and the FWD interface are coupled in sequence.
  • an in-band ripple suppression device is coupled between the ADC and the LNA circuit, and another in-band ripple suppression device is coupled between the DAC and the power amplifier circuit, due to the ADC, LNA, digital-to-analog converter and power amplifier circuit
  • the port has the characteristics of stable impedance. Therefore, the impedance adjustment module of the in-band fluctuation suppression device will not affect the characteristics of other front-end or back-end equipment after changing the impedance of the application circuit, ensuring the stability of the radio frequency system.
  • inserting an in-band fluctuation suppression device on the uplink and downlink can not only enhance the suppression ability of in-band fluctuation, but also insert the in-band fluctuation suppression device between stable impedance circuits so as not to affect the circuit stability. Wave, reducing the risk of link self-excitation.

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  • Computer Networks & Wireless Communication (AREA)
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Abstract

本申请涉及一种带内波动抑制装置和射频系统。其中，该带内波动抑制装置包括：阻抗调节模块和声表面波滤波器模块，阻抗调节模块耦合至声表面波滤波器模块；其中，阻抗调节模块用于调节应用电路的阻抗，以使得声表面波滤波器模块的频率响应特性与应用电路在工作频率范围内的带内波动的响应特性相反。通过本申请的方案，解决了相关技术中因采用FPGA抑制带内波动而对FPGA的运算频率要求高的问题，避免了带内波动抑制装置对FPGA的运算频率的依赖。

Description

带内波动抑制装置和射频系统
相关申请
本申请要求2019年11月04日申请的，申请号为201911065658.X，发明名称为“带内波动抑制装置和射频系统”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及通信技术领域，特别是涉及一种带内波动抑制装置和射频系统。
背景技术
直放站是一种基站射频拉远设备。直放站由天线、射频双工器、低噪声放大器、混频器、电调衰减器、滤波器、功率放大器等元器件或模块组成，包括上、下行两种链路。直放站工作的基本原理是：用前向天线将基站的下行信号接收进直放机，通过低噪放大器将有用信号放大，抑制信号中的噪声信号，提高信噪比；再经下变频至中频信号，经滤波器滤波，中频放大，再移频上变频至射频，经功率放大器放大，由后向天线发射到移动台；同时利用后向天线接收移动台上行信号，沿相反的路径由上行链路进行与下行链路相同的处理：即经过低噪放大器、下变频器、滤波器、中放、上变频器、功率放大器再发射到基站，从而达到基站与移动台的双向通信。
直放站或者其他的射频拉远设备的射频系统中，由于射频系统中模拟器件的搭配、数字信号干扰等会导致射频系统的工作频率范围内最大电平和最小电平存在差值，即带内波动。例如，双工器、滤波器在通带内频率响应的不平坦就会导致带内波动。
直放站或者其他的射频拉远设备中通常要求带内波动不大于3dB。在相关技术中通常采用现场可编程门阵列(Field Programmable Gate Array，简称FPGA)来抑制带内波动。例如，采用FPGA实现一个有限长单位冲激响应滤波器(Finite Impulse Response，简称FIR)后，通过在直放站的模数转换器(Analog-to-Digital Converter，简称ADC)后的数字中频信号加入FIR滤波器来补偿射频系统的带内波动。FIR滤波器抑制射频系统的带内波动的原理是根据原始的数字中频信号生成与带内波动的频率响应相反的反馈信号，并利用反馈信号对数字中频信号进行补偿，以抵消带内波动。然而，采用上述方式抑制带内波动不仅会导致FPGA资源被占用，还对FPGA的运算频率有比较高的要求。
发明内容
根据本申请的各种实施例，提供一种带内波动抑制装置，所述带内波动抑制装置包括：阻抗调节模块和声表面波滤波器模块，所述阻抗调节模块耦合至所述声表面波滤波器模块，其中，所述阻抗调节模块用于调节应用电路的阻抗，以使得所述声表面波滤波器模块的频率响应特性与所述应用电路在工作频率范围内的带内波动的响应特性相反。
在其中一个实施例中，所述阻抗调节模块耦合至所述声表面波滤波器模块的输入端和/或输出端。
在其中一个实施例中，所述阻抗调节模块包括：第一阻抗调节模块和第二阻抗调节模块，其中，所述第一阻抗调节模块耦合至所述声表面波滤波器模块的输入端，所述第二阻抗调节模块耦合至所述声表面波滤波器模块的输出端。
在其中一个实施例中，所述第一阻抗调节模块和所述第二阻抗调节模块具有相同的电路拓扑结构。
在其中一个实施例中，所述第一阻抗调节模块和所述第二阻抗调节模块具有不同的电路拓扑结构。
在其中一个实施例中，所述阻抗调节模块包括：一个或者多个阻抗调节子电路；所述多个阻抗调节子电路之间的连接方式为串联和/或并联。
在其中一个实施例中，所述阻抗调节子电路包括以下至少之一：L型阻抗调节子电路、T型阻抗调节子电路、π型阻抗调节子电路。
在其中一个实施例中，所述阻抗调节模块的参数的配置方式包括以下至少之一：在线调试配置、模拟仿真配置。
根据本申请的各种实施例，还提供一种射频系统，所述射频系统包括一个或多个所述带内波动抑制装置。
在其中一个实施例中，所述射频系统包括上行链路和下行链路；其中，在所述上行链路的两个稳定阻抗电路之间耦合有所述带内波动抑制装置，和/或在所述下行链路的两个稳定阻抗电路之间耦合有所述带内波动抑制装置。
本申请的有益效果如下：本申请的带内波动抑制装置采用阻抗调节模块调节应用电路的阻抗，以使得带内波动抑制装置的声表面波滤波器模块的频率响应特性与应用电路在工作频率范围内的带内波动的响应特性相反的方式，解决了相关技术中因采用FPGA抑制带内波动而对FPGA的运算频率要求高的问题，避免了带内波动抑制装置对FPGA的运算频率的依赖。
附图说明
为了更好地描述和说明这里公开的那些发明的实施例和/或示例，可以参考一幅或多幅附图。用于描述附图的附加细节或示例不应当被认为是对所公开的发明、目前描述的实施例和/或示例以及目前理解的这些发明的最佳模式中的任何一者的范围的限制。
图1是本申请实施例的带内波动抑制装置的结构框图。
图2是本申请实施例的在声表面波滤波器模块的电极阻抗与应用电路的阻抗匹配的情况下声表面波滤波器模块的输出波形的幅值图。
图3是本申请实施例的在声表面波滤波器模块的电极阻抗与应用电路的阻抗失配的情况下声表面波滤波器模块的输出波形的幅值图。
图4是本申请实施例的在声表面波滤波器模块的电极阻抗与应用电路的阻抗匹配的情况下声表面波滤波器模块的输出波形的相位图。
图5是本申请实施例的在声表面波滤波器模块的电极阻抗与应用电路的阻抗失配的情况下声表面波滤波器模块的输出波形的相位图。
图6是本申请实施例的阻抗调节子电路的拓扑图一。
图7是本申请实施例的阻抗调节子电路的拓扑图二。
图8是本申请实施例的阻抗调节子电路的拓扑图三。
图9是本申请实施例的带内波动抑制装置的拓扑图。
图10是本申请实施例的射频系统的结构框图。
具体实施方式
为了便于理解本申请，为使本申请的上述目的、特征和优点能够更加明显易懂，下面结合附图对本申请的具体实施方式做详细的说明。在下面的描述中阐述了很多具体细节以便于充分理解本申请，附图中给出了本申请的较佳实施方式。但是，本申请可以以许多不同的形式来实现，并不限于本文所描述的实施方式。相反地，提供这些实施方式的目的是使对本申请的公开内容理解的更加透彻全面。本申请能够以很多不同于在此描述的其它方式来实施，本领域技术人员可以在不违背本申请内涵的情况下做类似改进，因此本申请不受下面公开的具体实施例的限制。
显而易见地，下面描述中的附图仅仅是本申请的一些示例或实施例，对于本领域的普通技术人员而言，在不付出创造性劳动的前提下，还可以根据这些附图将本申请应用于其他类似情景。此外，还可以理解的是，虽然这种开发过程中所作出的努力可能是复杂并且冗长的，然而对于与本申请公开的内容相关的本领域的普通技术人员而言，在本申请揭露的技术内容的基础上进行的一些设计，制造或者生产等变更只是常规的技术手段，不应当理解为本 申请公开的内容不充分。
在本申请中提及“实施例”意味着，结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例，也不是与其它实施例互斥的独立的或备选的实施例。本领域普通技术人员显式地和隐式地理解的是，本申请所描述的实施例在不冲突的情况下，可以与其它实施例相结合。
除非另作定义，本申请所涉及的技术术语或者科学术语应当为本申请所属技术领域内具有一般技能的人士所理解的通常意义。本申请所涉及的“一”、“一个”、“一种”、“该”等类似词语并不表示数量限制，可表示单数或复数。本申请所涉及的术语“包括”、“包含”、“具有”以及它们任何变形，意图在于覆盖不排他的包含；例如包含了一系列步骤或模块(单元)的过程、方法、系统、产品或设备没有限定于已列出的步骤或单元，而是可以还包括没有列出的步骤或单元，或可以还包括对于这些过程、方法、产品或设备固有的其它步骤或单元。本申请所涉及的“连接”、“相连”、“耦接”等类似的词语并非限定于物理的或者机械的连接，而是可以包括电气的连接，不管是直接的还是间接的。本申请所涉及的“多个”、“各个”、“不同”是指两个或两个以上。“和/或”描述关联对象的关联关系，表示可以存在三种关系，例如，“A和/或B”可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。字符“/”一般表示前后关联对象是一种“或”的关系。本申请所涉及的术语“第一”、“第二”、“第三”等仅仅是区别类似的对象，不代表针对对象的特定排序。
在本申请实施例中提供了一种带内波动抑制装置。图1是本申请实施例的带内波动抑制装置的结构框图，如图1所示，该带内波动抑制装置包括：阻抗调节模块20和声表面波滤波器模块10，其中，阻抗调节模块20耦合至声表面波滤波器模块10。
其中，阻抗调节模块20用于调节应用电路的阻抗，以使得声表面波滤波器模块10的响应特性与应用电路在工作频率范围内的带内波动的响应特性相反。
上述带内波动抑制装置可以串联在直放站、光纤拉远单元等射频拉远单元的射频系统中，以抑制射频系统的带内波动。
其中，声表面波滤波器模块10通常由阻抗匹配网络和声表滤波器组成，其中，声表滤波器是利用石英、铌酸锂、钛酸钡晶体等具有压电效应的材料做成的。声表滤波器有输入叉指换能器和输出叉指换能器。当输入叉指换能器接上交流电压信号时，压电晶体基片的表面就产生振动，并激发出与外加信号同频率的声波，此声波主要沿着基片的表面的与叉指电极升起的方向传播，其中一个方向的声波被吸声材料吸收，另一方向的声波则传送到输出叉指换能器，被转换为电信号输出。
由于声表滤波器是通过叉指换能器进行声波信号和电信号的相互转换，因此，声表滤 波器具有三次回波的特性。即，在声表滤波器中，当声表面波形式的主信号到达输出电极时，通过输出叉指换能器的反压电效应转换成电信号输出。然而，此时也可以把输出电极看成是一个输入电极，于是输出电极的输出叉指换能器又通过压电效应把已转换为电信号形式的主信号的一部分又被转换成声表面波，向输入电极方向传送；在声表面波到达输入电极后，又以相似的形式被反射到输出电极，从而形成了多次回波，多次回波的存在导致声表滤波器的输出信号的幅值和相位发生变化进而降低输出信号的质量。
此外，声表面波滤波器模块接入的应用电路的阻抗对声表滤波器的三次回波会产生影响，进而影响声表面波滤波器模块的频率响应特性。下面将通过实验来说明声表面波滤波器模块接入的应用电路的阻抗对声表面波滤波器模块的频率响应特性的影响。
在电路中，标准阻抗通常为50欧姆或者75欧姆，这通常是由电路中的传输线阻抗决定的。在阻抗匹配的情况下，即信号源内阻与所接传输线的特性阻抗大小相等且相位相同或传输线的特性阻抗与所接负载阻抗的大小相等且相位相同的情况下，传输线能够获得最大功率或者传输线上携带的能量能够全部被负载所吸收。因此，声表面波滤波器模块的输入电极和输出电极上的电极阻抗通常被匹配网络调整为标准阻抗，声表面波滤波器模块的频率响应特性通常也是指其电极阻抗与所接入的应用电路的阻抗匹配的情况下的频率响应特性。
在实验中，被测的声表面波滤波器模块的电极阻抗为50欧姆，其通带为1710～1735MHz。在声表面波滤波器模块的输入电极和输出电极分别串联阻抗调节模块，以将应用电路的阻抗调节为与声表面波滤波器模块的电极阻抗匹配或者失配。在阻抗匹配和阻抗失配的情况下，向声表面波滤波器模块的输入端输入相同幅值和相位的方波，采用示波器分别观察声表面波滤波器模块的输出波形的幅值和相位的变化。
图2、图3分别示出了在通带1710～1735MHz内声表面波滤波器模块的电极阻抗与应用电路的阻抗匹配、失配情况下，声表面波滤波器模块的输出波形的幅值图。根据图2和图3可以观察到在应用电路的阻抗由与电极阻抗匹配变为与电极阻抗失配后，声表面波滤波器模块的波形的幅度发生了变化。
图4、图5分别示出了在通带1710～1735MHz内声表面波滤波器模块的电极阻抗与应用电路的阻抗匹配、失配的情况下，声表面波滤波器模块的输出波形的相位图。根据图4和图5可以观察到在应用电路的阻抗由与电极阻抗匹配变为与电极阻抗失配后，声表面波滤波器模块的波形的相位发生了变化。
发生上述变化的原因是应用电路的阻抗对声表滤波器内部的叉指换能器的振动产生影响，包括三次回波叠加后所表现的特性产生影响，改变了声表滤波器初始的表现。
上述实验结果表明了应用电路的阻抗变化将会影响声表面波滤波器模块的频率响应 特性。
在本申请实施例中，正是利用声表面波滤波器模块的响应特性受到应用电路阻抗影响的性质，得以通过调节应用电路的阻抗将声表面波滤波器模块的频率响应特性调节为与应用电路在工作频率范围内的带内波动的响应特性相反。
具体而言，在本实施例中，通过在声表面波滤波器模块10外加一个阻抗调节模块20对应用电路的阻抗进行调节，使得声表面波滤波器模块10的频率响应特性与应用电路在工作频率范围内的带内波动的响应特性相反，进而使得声表滤波器的三次回波与初始信号叠加而抵消初始信号的带内波动，实现应用电路在工作频率范围内的带内波动补偿。通过上述方式，使用阻抗调节模块20和声表面波滤波器模块10等模拟器件的配合有效地抑制带内波动，解决了相关技术中因采用FPGA抑制带内波动而对FPGA的运算频率要求高的问题，也避免了对FPGA资源的占用。此外，基于声表面波滤波器模块10的带内波动抑制装置还具有制造工艺简单、通带特性好、可靠性高、一致性高、体积小和通用性强的优点。
在本实施例中，可以根据应用电路的通带，选择与应用电路的通带相同或者略大于应用电路的通带的声表面波滤波器模块，搭建带内波动抑制装置，以实现对不同通带的应用电路的带内波动补偿。
在本实施例中，阻抗调节模块20可以串联耦合在声表面波滤波器模块10的输入端，也可以串联耦合在声表面波滤波器模块10的输出端，或者在声表面波滤波器模块10的输入端和输出端分别耦合阻抗调节模块20。作为优选，在声表面波滤波器模块10的输入端和输出端分别耦合阻抗调节模块20能够提高带内波动抑制的效果并简化阻抗调节模块20的参数的配置难度。
本实施例中的阻抗调节模块20可以由一个或者多个阻抗调节子电路组成。这些阻抗调节子电路包括但不限于以下至少之一：L型阻抗调节子电路、T型阻抗调节子电路、π型阻抗调节子电路。并且，每种类型的阻抗调节子电路的数量都可以根据需要配置，各个阻抗调节子电路之间的连接方式可以为串联和/或并联。
在一些实施例中，L型阻抗调节子电路是由电阻、电容和电感中的至少两种类型的元件组成的L型的电路。L型阻抗调节子电路具有线路简洁和成本低的优点。基于减少功率损耗方面的考虑，L型阻抗调节子电路尽量使用感性和容性元件，而尽量不使用电阻。因此，本实施例的L型阻抗调节子电路优选为图6中示出的8种电路中的一种。
在一些实施例中，T型阻抗调节子电路是由电阻、电容和电感中的至少两种类型的元件组成的T型的电路。基于减少功率损耗方面的考虑，T型阻抗调节子电路尽量使用感性和容性元件，而尽量不使用电阻。在图7中示出了两种优选的T型阻抗调节子电路。
在一些实施例中，π型阻抗调节子电路是由电阻、电容和电感中的至少两种类型的元件组成的π型的电路。基于减少功率损耗方面的考虑，π型阻抗调节子电路尽量使用感性和容性元件，而尽量不使用电阻。在图8中示出了两种优选的π型阻抗调节子电路。
此外，阻抗调节子电路比较优选的方案是采用电容与声表面波滤波器模块串联，电感与声表面波滤波器模块并联的方式，从而达到隔直流和提供静电泄放通道的作用。
可选地，在本实施例中提供了一种带内波动抑制装置。图9是本申请优选实施例的带内波动抑制装置的拓扑图，如图9所示，该带内波动抑制装置包括：四个电感、四个电容和声表面波滤波器模块10。其中，由一个电感和一个电容组成一个L型阻抗调节子电路，共四个L型阻抗调节子电路。其中两个L型阻抗调节子电路串联耦合之后再耦合到声表面波滤波器模块10的输入端，另外两个L型阻抗调节子电路串联耦合之后再耦合到声表面波滤波器模块10的输出端。
需要说明的是，虽然在图9中示出的声表面波滤波器模块10前端和后端串联的阻抗调节模块的电路拓扑结构是相同的，但是在本申请实施例中并不限于此，即声表面波滤波器模块10前端和后端串联的阻抗调节模块的电路拓扑结构也可以是不相同的。
在本实施例中，配置阻抗调节模块的参数的方式包括但不限于：在线调试配置和/或模拟仿真配置。其中的在线调试配置是指将阻抗调节模块串联到应用电路中，然后通过调试阻抗调节模块的各个参数并同时检测带内波动情况，最终将调试得到合适的阻抗调节模块的参数。其中的模拟仿真配置是指在计算机中对应用电路进行模拟仿真并测试各种阻抗调节模块的参数配置，得到能够满足需要的参数后，再按照模拟仿真得到的参数设计阻抗调节模块，最终接入实际的应用电路中实现带内波动的补偿。上述的参数配置方式也可以一同使用或者搭配其他参数配置方式使用。经过阻抗调节模块调整阻抗后的应用电路的阻抗与声表面波滤波器模块的电极阻抗可能是匹配的、也可能是失配的。
在实施例中还提供了一种射频系统。图10是本申请实施例的一种射频系统的结构框图，如图10所示，该射频系统包括一个或多个带内波动抑制装置，通过在射频系统内设置带内波动抑制装置，实现了射频系统的带内波动补偿。
其中，在本实施例中，射频系统包括上行链路和下行链路；其中，根据上下行链路的带内波动情况，可以选择性地在上行链路和/或下行链路中插入带内波动抑制装置来实现带内波动补偿。较优地，带内波动抑制装置插入在上行链路或下行链路的两个稳定阻抗电路之间。
在本实施例中，上行链路可以包括：低噪声放大器(LNA)电路、模数转换器(ADC)、第一带内波动抑制装置和反转运行(REV)接口，下行链路可以包括：功放电路、数模转换器(DAC)、第二带内波动抑制装置和正转运行(FWD)接口，其中，上行链路内的耦合关 系优选为：REV接口、LNA电路、第一带内波动抑制装置和ADC按依次耦合，下行链路内的耦合关系优选为：DAC、第二带内波动抑制装置、功放电路和FWD接口按依次耦合。在本实施例中将一个带内波动抑制装置耦合在ADC和LNA电路之间，将另一个带内波动抑制装置耦合在DAC和功放电路之间，由于ADC、LNA、数模转换器和功放电路的端口具有稳定阻抗的特点，因此，带内波动抑制装置的阻抗调节模块改变应用电路的阻抗后也不会影响其前端或者后端其他设备的特性，保证了射频系统的稳定性。
本实施例提供的射频系统，在上下行链路上插入带内波动抑制装置不仅能够增强带内波动的抑制能力，还通过将带内波动抑制装置插入在稳定阻抗电路之间从而不影响电路驻波、降低了链路自激风险。
以上所述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本申请的几种实施方式，其描述较为具体和详细，但并不能因此而理解为对发明专利范围的限制。应当指出的是，对于本领域的普通技术人员来说，在不脱离本申请构思的前提下，还可以做出若干变形和改进，这些都属于本申请的保护范围。因此，本申请专利的保护范围应以所附权利要求为准。

Claims (10)

  1. 一种带内波动抑制装置，其特征在于，所述带内波动抑制装置包括：阻抗调节模块和声表面波滤波器模块，所述阻抗调节模块耦合至所述声表面波滤波器模块，其中，
    所述阻抗调节模块用于调节应用电路的阻抗，以使得所述声表面波滤波器模块的频率响应特性与所述应用电路在工作频率范围内的带内波动的响应特性相反。
  2. 根据权利要求1所述的带内波动抑制装置，其特征在于，所述阻抗调节模块耦合至所述声表面波滤波器模块的输入端和/或输出端。
  3. 根据权利要求2所述的带内波动抑制装置，其特征在于，所述阻抗调节模块包括：第一阻抗调节模块和第二阻抗调节模块，其中，所述第一阻抗调节模块耦合至所述声表面波滤波器模块的输入端，所述第二阻抗调节模块耦合至所述声表面波滤波器模块的输出端。
  4. 根据权利要求3所述的带内波动抑制装置，其特征在于，所述第一阻抗调节模块和所述第二阻抗调节模块具有相同的电路拓扑结构。
  5. 根据权利要求3所述的带内波动抑制装置，其特征在于，所述第一阻抗调节模块和所述第二阻抗调节模块具有不同的电路拓扑结构。
  6. 根据权利要求1至5中任一项所述的带内波动抑制装置，其特征在于，所述阻抗调节模块包括：一个或者多个阻抗调节子电路；所述多个阻抗调节子电路之间的连接方式为串联和/或并联。
  7. 根据权利要求6所述的带内波动抑制装置，其特征在于，所述阻抗调节子电路包括以下至少之一：L型阻抗调节子电路、T型阻抗调节子电路、π型阻抗调节子电路。
  8. 根据权利要求1所述的带内波动抑制装置，其特征在于，所述阻抗调节模块的参数的配置方式包括以下至少之一：在线调试配置、模拟仿真配置。
  9. 一种射频系统，其特征在于，所述射频系统包括一个或多个如权利要求1至8中任一项所述的带内波动抑制装置。
  10. 根据权利要求9所述的射频系统，其特征在于，所述射频系统包括上行链路和下行链路；其中，在所述上行链路的两个稳定阻抗电路之间耦合有所述带内波动抑制装置，和/或在所述下行链路的两个稳定阻抗电路之间耦合有所述带内波动抑制装置。
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