Adaptive filter circuit, radio frequency circuit, chip and equipment

Abstract

The invention relates to a self-adaptive filter circuit, a radio frequency circuit, a chip and equipment. The adaptive filter circuit comprises a frequency modulation control module used for generating a corresponding frequency modulation control signal according to a second harmonic component output by a power module; the resonance module comprises a self-adaptive frequency modulation sub-module, the self-adaptive frequency modulation sub-module is used for adjusting the oscillation frequency generated by the resonance module based on the output signal of the power module and the frequency modulation control signal, and the oscillation frequency is used for filtering the second harmonic component; the output signal carries the second harmonic component; and the frequency modulation control module is also used for updating the frequency modulation control signal according to the filtered second harmonic component, so that the self-adaptive frequency modulation sub-module adjusts the oscillation frequency generated by the resonance module through the updated frequency modulation control signal, and the change of the harmonic component under different working conditions can be flexibly coped with. And it is ensured that the communication system can effectively suppress harmonic waves under various conditions.

Description

Technical Field

[0001] The present application relates to the field of radio frequency integrated circuit technology, and in particular to an adaptive filtering circuit, a radio frequency circuit, a chip and a device. Background Art

[0002] In modern communication systems, the performance of power amplifiers is crucial and directly affects the signal quality and overall system efficiency. During the operation of power amplifiers, the generation of second harmonics is a common problem, which not only reduces the purity of the signal, but also may cause mutual interference between systems, thus affecting the stability and reliability of the entire communication link.

[0003] Traditional harmonic suppression methods usually use capacitor arrays plus digital control to suppress second harmonics. However, due to PVT (Process Voltage and Temperature) deviations during chip production and use, the harmonic suppression effect is seriously deteriorated. The flexibility and adaptability of harmonic suppression are poor, which affects the stability of the power amplifier and makes it difficult to meet the needs of modern high-frequency, high-performance applications. Summary of the invention

[0004] Based on this, it is necessary to provide an adaptive filtering circuit, a radio frequency circuit, a chip and a device that can adaptively adjust the tuning frequency according to the changes to improve the stability of the power amplifier.

[0005] In a first aspect, the present application provides an adaptive filtering circuit, comprising:

[0006] A frequency modulation control module, used to generate a corresponding frequency modulation control signal according to the second harmonic component output by the power module;

[0007] A resonance module, comprising an adaptive frequency modulation submodule, wherein the adaptive frequency modulation submodule is used to adjust the oscillation frequency generated by the resonance module based on the output signal of the power module and the frequency modulation control signal, wherein the oscillation frequency is used to filter the second harmonic component; and the output signal carries the second harmonic component;

[0008] The frequency modulation control module is further used to update the frequency modulation control signal according to the filtered second harmonic component, so that the adaptive frequency modulation submodule adjusts the oscillation frequency generated by the resonance module through the updated frequency modulation control signal.

[0009] In one embodiment, the frequency modulation control module includes:

[0010] A down-mixer, wherein a first mixing input terminal of the down-mixer is connected to a second mixing input terminal of the down-mixer and then connected to the second harmonic component, and the down-mixer is used to convert the second harmonic frequency voltage in the second harmonic component into a first DC voltage;

[0011] an adder, wherein a first addend input terminal of the adder is connected to a mixing output terminal of the down-mixer and is used to receive the first DC voltage, a second addend input terminal of the adder is connected to a reference voltage, and the adder is used to add the first DC voltage and the reference voltage to obtain a first superimposed voltage;

[0012] an operational amplifier, wherein a first non-inverting input terminal of the operational amplifier is connected to a first signal output terminal of the adder for receiving the first superimposed voltage, a first inverting input terminal of the operational amplifier is connected to the reference voltage, a second signal output terminal of the operational amplifier is connected to the adaptive frequency modulation submodule, and the operational amplifier is used to generate a frequency modulation control signal according to the first superimposed voltage and the reference voltage, and provide the frequency modulation control signal to the adaptive frequency modulation submodule, so that the adaptive frequency modulation submodule adjusts the oscillation frequency generated by the resonance module based on the second harmonic component and the frequency modulation control signal.

[0013] In one of the embodiments, the first mixing input terminal of the down-mixer and the second mixing input terminal of the down-mixer are also used to access the filtered second harmonic component and convert the second harmonic frequency voltage in the filtered second harmonic component into a second DC voltage;

[0014] The first addend input terminal of the adder is also used to receive the second DC voltage, and add the second DC voltage to the reference voltage to obtain a second superimposed voltage;

[0015] The first non-inverting input terminal of the operational amplifier is also used to access the second superimposed voltage, and update the frequency modulation control signal according to the second superimposed voltage and the reference voltage, and provide the updated frequency modulation control signal to the adaptive frequency modulation sub-module, so that the adaptive frequency modulation sub-module can adjust the oscillation frequency generated by the resonance module through the updated frequency modulation control signal.

[0016] In one of the embodiments, the adaptive frequency modulation submodule includes a first capacitor;

[0017] One end of the first capacitor is connected to the output signal, and the other end of the first capacitor is connected to the frequency modulation control module. The first capacitor is used to adjust the oscillation frequency generated by the resonance module according to the difference between the voltage of the output signal and the control voltage in the frequency modulation control signal.

[0018] In one embodiment, the first capacitor is a variable capacitor.

[0019] In one of the embodiments, the resonance module further includes a second capacitor and a first inductor;

[0020] One end of the second capacitor is connected to a common end of the first capacitor and the frequency modulation control module, and the other end of the first capacitor is grounded via the first inductor.

[0021] In a second aspect, the present application provides a radio frequency circuit, the radio frequency circuit comprising a power module, a signal conversion module, the adaptive filtering circuit as described above, and a radio frequency module; wherein:

[0022] The power module is used to access the radio frequency signal, and after amplifying the radio frequency signal, differentially output the amplified radio frequency signal to obtain an output signal, wherein the output signal includes a second harmonic component and a fundamental frequency component;

[0023] The signal conversion module is used to convert the fundamental frequency component into a single-ended signal, and to provide the second harmonic component to the adaptive filtering circuit;

[0024] The adaptive filtering circuit is used to adaptively filter the second harmonic component to filter out the second harmonic component;

[0025] The radio frequency module is used to output the single-ended signal.

[0026] In one embodiment, the power module comprises:

[0027] A power amplifier, wherein the second in-phase input terminal and the second inverting input terminal of the power amplifier are used as the power module to access the radio frequency signal, the first differential output terminal and the second differential output terminal of the power amplifier are connected to the signal conversion module, the radio frequency signal includes a first input signal connected to the second in-phase input terminal and a second input signal connected to the second inverting input terminal, and the power amplifier is used to amplify the first input signal and the second input signal respectively, and output the amplified first input signal through the first differential output terminal, and output the amplified second input signal through the second differential output terminal to obtain an output signal.

[0028] In one embodiment, the power module further includes:

[0029] A second inductor, one end of which is connected to a power supply, and the other end of which is connected to the signal conversion module, the frequency modulation control module and the resonance module.

[0030] In one embodiment, the signal conversion module includes a balun converter, and the balun converter includes a primary coil and a secondary coil coupled to the primary coil;

[0031] The first end of the primary coil is connected to the first differential output end, the second end of the primary coil is connected to the second differential output end, the third end of the primary coil is connected to the power module, the frequency modulation control module and the resonance module, the primary coil is used to convert the fundamental frequency component into a balanced signal and couple it to the secondary coil, and is used to transmit the second harmonic component to the frequency modulation control module and the resonance module;

[0032] A first end of the secondary coil is connected to the radio frequency module to provide the single-ended signal to the radio frequency module, and a second end of the secondary coil is grounded.

[0033] In a third aspect, the present application provides a radio frequency chip, wherein the radio frequency chip integrates the adaptive filtering circuit as described above or integrates the radio frequency circuit as described above.

[0034] In a fourth aspect, the present application provides a radio frequency device, comprising the radio frequency chip as described above.

[0035] The above-mentioned adaptive filtering circuit, radio frequency circuit, chip and device, by setting a resonance module to filter the second harmonic component carried in the output signal of the power module at the resonance frequency, can effectively filter out unnecessary harmonic components in the output signal, which is beneficial to improve the purity of the signal, thereby avoiding mutual interference between signals in the communication system, and ensuring the stability and reliability of the entire communication link; at the same time, a frequency modulation control module is set, and by accessing the second harmonic component, the change of the second harmonic component can be monitored in real time. When the second harmonic component changes, the frequency modulation control module can generate a corresponding frequency modulation control signal based on the changed second harmonic component, and the frequency modulation control The signal acts on the adaptive regulation submodule of the resonance module, so that the adaptive frequency modulation submodule adjusts the oscillation frequency generated by the resonance module through the updated frequency modulation control signal, thereby realizing adaptive regulation of the oscillation frequency, and ensuring that the resonance module always operates at an oscillation frequency matching the second harmonic component to cope with possible frequency changes in the output signal of the power module, thereby further enhancing the stability and reliability of the entire communication system. Moreover, by dynamically adjusting the oscillation frequency of the resonance module, it is also possible to more flexibly cope with changes in harmonic components under different working conditions, ensuring that the communication system can effectively suppress harmonics under various conditions to meet changing communication needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 is a structural block diagram of an adaptive filtering circuit according to an embodiment;

[0038] Figure 2 is a circuit schematic diagram of an adaptive filtering circuit of an embodiment;

[0039] Figure 3 is a structural block diagram of a radio frequency circuit according to an embodiment;

[0040] Figure 4 is a circuit schematic diagram of a radio frequency circuit of an embodiment;

[0041] Figure 5 A schematic diagram of the frequencies of the fundamental frequency component and the second harmonic component before and after the second harmonic component is regulated by the resonance module of this embodiment;

[0042] Figure 6 The diagram is a frequency diagram of the fundamental frequency component and the second harmonic component before and after the second harmonic component is regulated by the frequency modulation control module and the resonance module of the present application.

[0043] Description of reference numerals:

[0044] Frequency modulation control module 101, resonance module 102;

[0045] Down-mixer mix, adder add, operational amplifier A, first capacitor C1, second capacitor C2, first inductor L1;

[0046] Power module 301, signal conversion module 302, adaptive filter circuit 303, radio frequency module 304;

[0047] The second inductor L2, the power amplifier PA, and the balun converter BL. DETAILED DESCRIPTION

[0048] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0050] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0051] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0052] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0053] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0054] In the process of wireless communication, since the RF signal is usually very weak, it needs to be amplified. As the main part of the transmission system, the power module is mainly used to amplify the weak RF signal into a higher power signal. In wireless communication, the RF signal is usually very weak and needs to be amplified by a power amplifier so that it has enough energy to cover the target transmission area to ensure that the signal can be transmitted to the target transmission area. The performance of the power module directly determines the stability of the signal. However, during the operation of the power module, as the signal is transmitted and processed, the output signal of the power module includes a DC signal and a second harmonic component. The second harmonic component refers to a signal with a frequency twice the original signal frequency. When the current flows through a nonlinear load, a non-sinusoidal current is formed, thereby generating harmonics. Among the generated harmonics, the component with a frequency twice the fundamental frequency is the second harmonic. The generation of second harmonics will interfere with the communication system through electromagnetic induction or capacitive coupling, causing distortion or interruption of the communication signal, thereby affecting the stability and reliability of the entire communication link. Therefore, it is necessary to optimize the design of the power amplifier module to improve the filtering of the second harmonic components, thereby improving the signal's anti-interference ability and ensuring that the signal will not be excessively interfered with and attenuated during transmission.

[0055] In one embodiment, Figure 1 As shown, an adaptive filtering circuit is provided, including a frequency modulation control module 101 and a resonance module 102 .

[0056] The frequency modulation control module 101 is used to control the frequency modulation control module 101 according to the power module 301 ( Figure 3 ) generates a corresponding frequency modulation control signal based on the second harmonic component output by the power module 301. The resonance module 102 includes an adaptive frequency modulation submodule, which is used to adjust the oscillation frequency generated by the resonance module 102 based on the output signal of the power module 301 and the frequency modulation control signal. The oscillation frequency is used to filter the second harmonic component; the output signal carries the second harmonic component. The frequency modulation control module 101 is also used to update the frequency modulation control signal according to the filtered second harmonic component, so that the adaptive frequency modulation submodule adjusts the oscillation frequency generated by the resonance module 102 through the updated frequency modulation control signal.

[0057] For example, when transmitting a signal, the power module 301 receives a radio frequency signal, amplifies the radio frequency signal, and outputs the signal. The output signal of the power module 301 is synchronously transmitted to the frequency modulation control module 101 and the adaptive frequency modulation submodule of the resonance module 102. The first end ( Figure 1 Node a1 in the adaptive frequency modulation submodule) and the first end of the adaptive frequency modulation submodule ( Figure 1The frequency modulation control module 101 generates a frequency modulation control signal matching the second harmonic component according to the second harmonic component in the output signal and transmits the frequency modulation control signal to the second end ( Figure 1 The node a2 in the adaptive frequency modulation submodule is transmitted to the second end ( Figure 1 Node b2 in the figure), so that the adaptive frequency modulation module generates a corresponding oscillation frequency according to the input signal at its first end and the frequency modulation control signal at its second end, so that the resonance module 102 as a whole filters the second harmonic component in the input signal under the action of the oscillation frequency.

[0058] With the filtering of the second harmonic component and the continuous transmission of the RF signal, when the second harmonic component in the power module 301 changes, the changed second harmonic component is synchronously transmitted to the frequency modulation control module 101 and the adaptive frequency modulation submodule of the resonance module 102 along with the output signal, so that the frequency modulation control module 101 updates the frequency modulation control signal according to the changed second harmonic component and transmits the updated frequency modulation control signal to the adaptive frequency modulation submodule, so that the adaptive frequency modulation submodule adjusts the oscillation frequency generated by the resonance module 102 according to the updated frequency modulation control signal and the current output signal, thereby realizing adaptive adjustment of the oscillation frequency.

[0059] The above-mentioned adaptive filtering circuit, by setting the resonance module 102 to filter the second harmonic component carried in the output signal of the power module 301 at the resonance frequency, can effectively filter out the unnecessary harmonic components in the output signal, which is beneficial to improve the purity of the signal, thereby avoiding mutual interference between signals in the communication system, and ensuring the stability and reliability of the entire communication link; at the same time, the frequency modulation control module 101 is set, and by accessing the second harmonic component, the change of the second harmonic component can be monitored in real time. When the second harmonic component changes, the frequency modulation control module 101 can generate a corresponding frequency modulation control signal based on the changed second harmonic component, and the frequency modulation control signal acts on the resonance module The adaptive adjustment submodule of block 102 adjusts the oscillation frequency generated by the resonance module 102 through the updated frequency modulation control signal by the adaptive frequency modulation submodule to achieve adaptive adjustment of the oscillation frequency, which can ensure that the resonance module 102 always operates at an oscillation frequency that matches the second harmonic component to cope with possible frequency changes in the output signal of the power module 301, thereby further enhancing the stability and reliability of the entire communication system. In addition, by dynamically adjusting the oscillation frequency of the resonance module 102, it is also possible to more flexibly cope with changes in harmonic components under different working conditions, ensuring that the communication system can effectively suppress harmonics under various conditions to meet changing communication needs.

[0060] In one embodiment, Figure 2As shown, the frequency modulation control module 101 includes a down-mixer mix, an adder add and an operational amplifier A.

[0061] Among them, the first mixing input terminal of the down-mixer mix and the second mixing input terminal of the down-mixer mix are connected to form the first end of the frequency modulation control module 101, the mixing output terminal of the down-mixer mix is ​​connected to the first addend input terminal of the adder add, the second addend input terminal of the adder add is connected to the reference voltage, the first signal output terminal of the adder add is connected to the first in-phase input terminal of the operational amplifier A, the first inverting input terminal of the operational amplifier A is connected to the reference voltage, and the second signal output terminal of the operational amplifier A is connected to the second end of the adaptive frequency modulation sub-module.

[0062] The down-mixer mix is ​​used to convert the second harmonic frequency voltage in the second harmonic component into a first DC voltage, and transmit the first DC voltage to the first addend input terminal of the adder add. Specifically, the first mixing input terminal of the down-mixer mix is ​​used as the local oscillator terminal of the down-mixer mix and the second mixing input terminal is used as the radio frequency terminal of the down-mixer mix to access the second harmonic component, or the first mixing input terminal is used as the radio frequency terminal and the second mixing input terminal is used as the local oscillator terminal to access the second harmonic component, so that the first mixing input terminal and the second mixing input terminal are both connected to the same second harmonic component, and the frequency of the accessed signal is the same. After being processed by the down-mixer mix, the frequency of the second harmonic component can be filtered out, and a signal without frequency, i.e., the first DC voltage, is output through the mixing output terminal of the down-mixer mix.

[0063] The adder add is used to add the first DC voltage and the reference voltage to obtain a first superimposed voltage, and transmit the first superimposed voltage to the first non-inverting input terminal of the operational amplifier A. Specifically, the first addend input terminal of the adder add is connected to the first DC voltage as the addend input terminal of the adder add, and the second addend input terminal is connected to the external reference voltage as the augend input terminal of the adder add, or the first addend input terminal of the adder add is connected to the first DC voltage as the augend input terminal of the adder add, and the second addend input terminal is connected to the reference voltage as the addend input terminal of the adder add, so as to add the first DC voltage and the reference voltage to obtain the first superimposed voltage.

[0064] The operational amplifier A is used to generate a frequency modulation control signal according to the first superimposed voltage and the reference voltage, and provide the frequency modulation control signal to the adaptive frequency modulation submodule, so that the adaptive frequency modulation submodule adjusts the oscillation frequency generated by the resonance module 102 based on the second harmonic component and the frequency modulation control signal. Specifically, the first in-phase input terminal of the operational amplifier A is connected to the first superimposed voltage, and the first inverting input terminal is connected to the reference voltage. The operational amplifier A generates a corresponding control voltage based on the first superimposed voltage and the reference voltage as a frequency modulation control signal and provides it to the adaptive frequency modulation submodule.

[0065] Among them, the control voltage generated by operational amplifier A is expressed as:

[0066] (1)

[0067] in, is the control voltage, also known as the frequency modulation control signal, is the voltage connected to the first non-inverting input terminal of the operational amplifier. is the reference voltage, is the voltage connected to the first inverting input terminal of the operational amplifier, is the feedback resistor, is the input resistance.

[0068] Since the reference voltage is added to the first superimposed voltage, it is equivalent to connecting the reference voltage to both the first non-inverting input terminal and the second non-inverting input terminal of the operational amplifier, that is, , , is the first DC voltage, so the frequency modulation control signal is expressed as:

[0069] (2)

[0070] It can be seen that the frequency modulation control signal is the sum of the amplified value of the first DC voltage and the reference voltage. This is beneficial to reducing the influence of the common mode voltage, thereby improving the anti-interference ability of the circuit and ensuring the generation of a stable and reliable frequency modulation control signal.

[0071] As an optional method of this embodiment, when the second harmonic component changes, the first mixing input terminal of the down mixer mix and the second mixing input terminal of the down mixer mix are also used to access the filtered second harmonic component, and convert the second harmonic frequency voltage in the filtered second harmonic component into a second DC voltage; the first addend input terminal of the adder add is also used to access the second DC voltage, and add the second DC voltage to the reference voltage to obtain a second superimposed voltage; the first in-phase input terminal of the operational amplifier A is also used to access the second superimposed voltage, and update the frequency modulation control signal according to the second superimposed voltage and the reference voltage, and provide the updated frequency modulation control signal to the adaptive frequency modulation submodule, so that the adaptive frequency modulation submodule adjusts the oscillation frequency generated by the resonance module 102 through the updated frequency modulation control signal. In this embodiment, the process of the down mixer mix, the adder add and the operational amplifier A generating a new frequency modulation control signal based on the changed second harmonic component can be referred to the record of the above process, and will not be repeated here.

[0072] In this embodiment, on the one hand, by simultaneously inputting the second harmonic component into the first mixing input terminal and the second mixing input terminal of the down-mixer mix to eliminate the frequency of the second harmonic component, a first DC voltage without frequency is obtained, which is used as a basis for subsequent frequency modulation control signal generation, which is beneficial to reducing the interference of the high-frequency signal on the first DC voltage signal and ensuring the generation of a stable and reliable frequency modulation control signal; on the other hand, the first DC voltage is superimposed with the reference voltage and used as the input signal of the first non-inverting input terminal of the operational amplifier A, and the reference voltage is used as the input signal of the first inverting input terminal of the operational amplifier A, so that the output frequency modulation control signal is the sum of the amplified value of the first DC voltage and the reference voltage, which is beneficial to reducing the influence of the common-mode voltage, thereby improving the anti-interference ability of the circuit and ensuring the generation of a stable and reliable frequency modulation control signal.

[0073] In one embodiment, the adaptive frequency modulation submodule includes a first capacitor C1.

[0074] One end of the first capacitor C1 is connected to the output signal, and the other end of the first capacitor C1 is connected to the frequency modulation control module 101 .

[0075] The first capacitor C1 is used to adjust the oscillation frequency generated by the resonance module 102 according to the difference between the voltage of the output signal and the control voltage in the frequency modulation control signal.

[0076] The first capacitor C1 is a variable capacitor, and its capacitance can be changed with the change of the voltage at both ends. Specifically, one end of the first capacitor C1 is connected to the input signal as the first end of the adaptive frequency modulation submodule, and the other end of the first capacitor C1 is connected to the frequency modulation control signal as the second end of the adaptive frequency modulation submodule, so that the first capacitor C1 can adjust its own capacitance according to the input signal at both ends and the frequency modulation control signal, so as to achieve the purpose of adjusting the oscillation frequency.

[0077] In this embodiment, a variable capacitor is used as the first capacitor C1. When the voltage across the first capacitor C1 (i.e., the input signal and the frequency modulation control signal) changes, the first capacitor C1 responds to the voltage change by changing its own capacitance, thereby achieving the purpose of adjusting the oscillation frequency. The entire process only requires setting one capacitor, which is beneficial to saving digital resources, is not limited by the number of adjustment bits, and has high adaptability.

[0078] In one embodiment, the resonance module 102 further includes a second capacitor C2 and a first inductor L1.

[0079] One end of the second capacitor C2 is connected to a common end of the first capacitor C1 and the frequency modulation control module 101 , and the other end of the first capacitor C1 is grounded via the first inductor L1 .

[0080] The second capacitor C2 is connected in series with the first inductor L1 to form an LC oscillation circuit, and the interaction between the first inductor L1 and the second capacitor C2 is used to generate a continuous AC signal. When the second capacitor C2 is charged, the electric field energy increases and the magnetic field energy decreases; when the second capacitor C2 is discharged, the electric field energy decreases and the magnetic field energy increases. Through the mutual conversion between the electric field energy and the magnetic field energy, the current and voltage in the oscillation circuit show periodic changes, thereby forming oscillation to achieve filtering of the second harmonic component.

[0081] In this embodiment, by setting the second capacitor C2 and the first inductor L1, an oscillation source can be formed together with the first capacitor C1. When the second harmonic component passes through the first capacitor C1, the second capacitor C2 and the first inductor L1, the second harmonic component is attenuated due to the blocking effect of the capacitor and the inductor on the signal, thereby achieving the filtering of the second harmonic component.

[0082] In one embodiment, Figure 3 As shown, a radio frequency circuit is provided, including: a power module 301, a signal conversion module 302, an adaptive filtering circuit 303 and a radio frequency module 304; wherein the adaptive filtering circuit 303 is implemented by the adaptive filtering circuit 303 in the above embodiment, and the details can be referred to the relevant records of the above embodiment, which will not be elaborated in this embodiment.

[0083] The input end of the power module 301 is connected to the RF signal, the output end of the power module 301 is connected to the input end of the signal conversion module 302, and the output end of the signal conversion module 302 is also connected to the adaptive filtering circuit 303 and the RF module 304 respectively.

[0084] Among them, the power module 301 is used to access the RF signal, and after amplifying the RF signal, differentially output the amplified RF signal to obtain an output signal, which includes a second harmonic component and a fundamental frequency component; the signal conversion module 302 is used to convert the fundamental frequency component into a single-ended signal, and to provide the second harmonic component to the adaptive filtering circuit 303; the adaptive filtering circuit 303 is used to adaptively filter the second harmonic component to filter out the second harmonic component; the RF module 304 is used to output the single-ended signal.

[0085] Exemplarily, the input end of the power module 301 is connected to a radio frequency signal, the radio frequency signal is amplified by the power module 301 to obtain an amplified radio frequency signal, and the amplified radio frequency signal is differentially output through the output end of the power module 301 to obtain an output signal. Subsequently, the output signal flowing out through the output end of the power module 301 flows into the signal conversion module 302 through the input end of the signal conversion module 302. Since the baseband signal in the output signal is in differential mode, a virtual ground point is formed at the center of the signal conversion module 302, so that the baseband component does not flow into the adaptive filtering circuit 303 through the signal conversion module 302, but is converted into a single-ended signal through the signal conversion module 302 and then output to the RF module 304; and since the second harmonic component in the output signal is in common mode, the second harmonic component can flow into the adaptive filtering circuit 303 through the signal conversion module 302 after being transmitted to the signal conversion module 302. At the same time, since the oscillation frequency of the resonance module 102 in the adaptive filtering circuit 303 matches the frequency of the second harmonic component, that is, the resonance module 102 works at the second harmonic frequency, it can form an equivalent short circuit for the second harmonic component, so that the current generated by the second harmonic component flows to the reference ground through the resonance module 102, and will not interfere with the transmission of the baseband component, thereby achieving the purpose of suppressing the second harmonic and improving the signal transmission quality.

[0086] In this embodiment, the signal conversion module 302 is set to separate the second harmonic component from the output signal and provide the second harmonic component to the adaptive filtering circuit 303, so that the adaptive filtering circuit 303 can accurately filter out the second harmonic component, reduce high-frequency interference in the signal, so as to improve the purity and quality of the output signal; and the adaptive filtering circuit 303 can automatically adjust the oscillation frequency according to the change of the second harmonic component, realize flexible processing of different frequency components, and enhance the adaptability and flexibility of the system.

[0087] like Figure 4 As shown, in one embodiment, the power module 301 includes a power amplifier PA.

[0088] The second in-phase input terminal and the second inverting input terminal of the power amplifier PA are connected to the RF signal as the power module 301, and the first differential output terminal and the second differential output terminal of the power amplifier PA are connected to the signal conversion module 302. The RF signal includes a first input signal Fin_P connected to the second in-phase input terminal and a second input signal Fin_N connected to the second inverting input terminal.

[0089] The power amplifier PA is used to amplify the first input signal Fin_P and the second input signal Fin_N respectively, and output the amplified first input signal Fin_P through the first differential output terminal, and output the amplified second input signal Fin_N through the second differential output terminal to obtain output signals.

[0090] Exemplarily, the second in-phase input terminal and the second inverting input terminal of the power amplifier PA are connected to the RF signal as the input terminal of the power amplifier PA, and the first differential output terminal and the second differential output terminal of the power amplifier PA are connected to the signal conversion module 302 as the output terminal of the power amplifier PA to transmit the output signal to the signal conversion module 302; specifically, after the power amplifier PA is connected to the RF signal, it amplifies the RF signal to obtain an amplified RF signal. For the amplified RF signal, the power amplifier PA separates the RF signal into two signals, one signal as a positive signal and the other signal as a negative signal, the two signals are the same in amplitude but opposite in phase, and then the power amplifier PA performs differential processing on the separated positive and negative signals, and calculates the difference between the positive and negative signals to obtain the output signal.

[0091] In this embodiment, by performing differential processing on the radio frequency signal and then outputting it, common mode noise and interference can be effectively suppressed, and the purity and stability of the output signal can be improved.

[0092] In one embodiment, the power module 301 further includes a second inductor L2.

[0093] One end of the second inductor L2 is connected to the power supply, and the other end of the second inductor L2 is connected to the signal conversion module 302 , the frequency modulation control module 101 and the resonance module 102 .

[0094] The second inductor L2 is used to reduce the common-mode interference in the power supply VDD, so as to ensure that a stable and reliable power supply is provided to the power module 301 .

[0095] In this embodiment, by providing the second inductor L2 at the output end of the power supply VDD, common-mode interference can be further reduced to ensure stable operation of the power amplifier PA.

[0096] In one embodiment, the signal conversion module 302 includes a balun converter BL, and the balun converter BL includes a primary coil and a secondary coil coupled to the primary coil.

[0097] Among them, the first end of the primary coil is connected to the first differential output end, the second end of the primary coil is connected to the second differential output end, the third end of the primary coil is connected to the power module 301, the frequency modulation control module 101 and the resonance module 102, the first end of the secondary coil is connected to the RF module 304, and the second end of the secondary coil is grounded.

[0098] The primary coil is used to convert the fundamental frequency component into a balanced signal and couple it to the secondary coil, and to transmit the second harmonic component to the frequency modulation control module 101 and the resonance module 102 ; the secondary coil is used to provide a single-ended signal to the RF module 304 .

[0099] Exemplarily, the primary coil receives the fundamental frequency component and the second harmonic component from the power module 301 through its first end and the second end. Since the first end and the second end of the primary coil are respectively connected to the first differential output end and the second differential output end, they constitute the input port of the balanced signal; after the fundamental frequency component and the second harmonic component are connected, for the fundamental frequency signal, the primary coil uses the principle of electromagnetic induction to convert the received fundamental frequency component signal into a single-ended signal, and couples the single-ended signal to the secondary coil, and provides it to the RF module 304 through the secondary coil to send the RF signal outward; for the second harmonic component, the third end of the primary coil (that is, the tap of the primary coil) transmits the second harmonic component to the frequency modulation control module 101 and the resonance module 102, so that the frequency modulation control module 101 and the resonance module 102 can filter the second harmonic component. Specifically, the third end of the primary coil is connected to the corresponding end of the first capacitor C1 to transfer the output signal to the first capacitor C1, and the third section of the primary coil is also connected to both the first mixing signal input end and the second mixing input end to provide the second harmonic component to the down mixer mix.

[0100] In this embodiment, a balun converter BL is provided to receive the fundamental frequency component and the second harmonic component from the power module 301. The fundamental frequency signal is converted by the balun converter BL, and the single-ended signal obtained after the conversion can be provided to the radio frequency signal. At the same time, the balun converter BL also provides the second harmonic component to the adaptive filtering circuit 303, which can suppress the second harmonic component and ensure stable communication.

[0101] like Figure 5, which is a frequency diagram of the fundamental frequency component and the second harmonic component before and after the second harmonic component is regulated by the resonance module 102 of this embodiment only, wherein: Figure 5 (a) is a schematic diagram of the fundamental frequency component (i.e., f_rf) and the second harmonic component (i.e., 2*f_rf) before regulation. Figure 5 (b) is a schematic diagram of the fundamental frequency component and the second harmonic component after regulation. It can be seen that the second harmonic component is well suppressed.

[0102] like Figure 6 , which is a frequency diagram of the fundamental frequency component and the second harmonic component before and after the frequency modulation control module 101 and the resonance module 102 of the present application jointly regulate the second harmonic component, wherein: Figure 6 (a) is a schematic diagram of the fundamental frequency component and the second harmonic component before regulation. It can be seen that the second harmonic component before regulation fluctuates greatly with PVT changes and has poor stability. Figure 6 (b) is a schematic diagram of the fundamental frequency component and the second harmonic component before regulation. It can be seen that after regulation, the second harmonic component fluctuates less with PVT changes and has high stability. While achieving harmonic suppression, it also improves the stability of the harmonic suppression effect when PVT changes.

[0103] In one embodiment, a radio frequency chip is provided. The radio frequency chip integrates the adaptive filtering circuit 303 of the above embodiment or integrates the radio frequency circuit of the above embodiment.

[0104] In one embodiment, a radio frequency device is provided. The radio frequency device includes the radio frequency chip according to the above embodiment.

[0105] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0106] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0107] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. An adaptive filtering circuit, characterized in that: include: A frequency modulation control module, used to generate a corresponding frequency modulation control signal according to the second harmonic component output by the power module; A resonance module, comprising an adaptive frequency modulation submodule, wherein the adaptive frequency modulation submodule is used to adjust the oscillation frequency generated by the resonance module based on the output signal of the power module and the frequency modulation control signal, wherein the oscillation frequency is used to filter the second harmonic component; and the output signal carries the second harmonic component; The frequency modulation control module is further used to update the frequency modulation control signal according to the filtered second harmonic component, so that the adaptive frequency modulation submodule adjusts the oscillation frequency generated by the resonance module through the updated frequency modulation control signal.

2. The adaptive filtering circuit according to claim 1, characterized in that: The frequency modulation control module comprises: A down-mixer, wherein a first mixing input terminal of the down-mixer is connected to a second mixing input terminal of the down-mixer and then connected to the second harmonic component, and the down-mixer is used to convert the second harmonic frequency voltage in the second harmonic component into a first DC voltage; an adder, wherein a first addend input terminal of the adder is connected to a mixing output terminal of the down-mixer and is used to receive the first DC voltage, a second addend input terminal of the adder is connected to a reference voltage, and the adder is used to add the first DC voltage and the reference voltage to obtain a first superimposed voltage; an operational amplifier, wherein a first non-inverting input terminal of the operational amplifier is connected to a first signal output terminal of the adder for receiving the first superimposed voltage, a first inverting input terminal of the operational amplifier is connected to the reference voltage, a second signal output terminal of the operational amplifier is connected to the adaptive frequency modulation submodule, and the operational amplifier is used to generate a frequency modulation control signal according to the first superimposed voltage and the reference voltage, and provide the frequency modulation control signal to the adaptive frequency modulation submodule, so that the adaptive frequency modulation submodule adjusts the oscillation frequency generated by the resonance module based on the second harmonic component and the frequency modulation control signal.

3. The adaptive filtering circuit according to claim 2, characterized in that: The first mixing input terminal of the down-mixer and the second mixing input terminal of the down-mixer are also used to access the filtered second harmonic component and convert the second harmonic frequency voltage in the filtered second harmonic component into a second DC voltage; The first addend input terminal of the adder is also used to receive the second DC voltage, and add the second DC voltage to the reference voltage to obtain a second superimposed voltage; The first non-inverting input terminal of the operational amplifier is also used to access the second superimposed voltage, and update the frequency modulation control signal according to the second superimposed voltage and the reference voltage, and provide the updated frequency modulation control signal to the adaptive frequency modulation sub-module, so that the adaptive frequency modulation sub-module can adjust the oscillation frequency generated by the resonance module through the updated frequency modulation control signal.

4. The adaptive filtering circuit according to claim 1, characterized in that: The adaptive frequency modulation submodule includes a first capacitor; One end of the first capacitor is connected to the output signal, and the other end of the first capacitor is connected to the frequency modulation control module. The first capacitor is used to adjust the oscillation frequency generated by the resonance module according to the difference between the voltage of the output signal and the control voltage in the frequency modulation control signal.

5. The adaptive filtering circuit according to claim 4, characterized in that: The first capacitor is a variable capacitor.

6. The adaptive filtering circuit according to claim 4, characterized in that: The resonance module also includes a second capacitor and a first inductor; One end of the second capacitor is connected to a common end of the first capacitor and the frequency modulation control module, and the other end of the first capacitor is grounded via the first inductor.

7. A radio frequency circuit, characterized in that: The radio frequency circuit comprises a power module, a signal conversion module, an adaptive filtering circuit according to any one of claims 1 to 6, and a radio frequency module; wherein: The power module is used to access the radio frequency signal, and after amplifying the radio frequency signal, differentially output the amplified radio frequency signal to obtain an output signal, wherein the output signal includes a second harmonic component and a fundamental frequency component; The signal conversion module is used to convert the fundamental frequency component into a single-ended signal, and to provide the second harmonic component to the adaptive filtering circuit; The adaptive filtering circuit is used to adaptively filter the second harmonic component to filter out the second harmonic component; The radio frequency module is used to output the single-ended signal.

8. The radio frequency circuit according to claim 7, characterized in that: The power module comprises: A power amplifier, wherein the second in-phase input terminal and the second inverting input terminal of the power amplifier are used as the power module to access the radio frequency signal, the first differential output terminal and the second differential output terminal of the power amplifier are connected to the signal conversion module, the radio frequency signal includes a first input signal connected to the second in-phase input terminal and a second input signal connected to the second inverting input terminal, and the power amplifier is used to amplify the first input signal and the second input signal respectively, and output the amplified first input signal through the first differential output terminal, and output the amplified second input signal through the second differential output terminal to obtain an output signal.

9. The radio frequency circuit according to claim 8, characterized in that: The power module further comprises: A second inductor, one end of which is connected to a power supply, and the other end of which is connected to the signal conversion module, the frequency modulation control module and the resonance module.

10. The radio frequency circuit according to claim 8, characterized in that: The signal conversion module includes a balun converter, and the balun converter includes a primary coil and a secondary coil coupled to the primary coil; The first end of the primary coil is connected to the first differential output end, the second end of the primary coil is connected to the second differential output end, the third end of the primary coil is connected to the power module, the frequency modulation control module and the resonance module, the primary coil is used to convert the fundamental frequency component into a balanced signal and couple it to the secondary coil, and is used to transmit the second harmonic component to the frequency modulation control module and the resonance module; A first end of the secondary coil is connected to the radio frequency module to provide the single-ended signal to the radio frequency module, and a second end of the secondary coil is grounded.

11. A radio frequency chip, characterized in that: The radio frequency chip is integrated with the adaptive filtering circuit as described in any one of claims 1 to 6 or is integrated with the radio frequency circuit as described in any one of claims 7 to 10.

12. A radio frequency device, characterized in that: Comprising the radio frequency chip as claimed in claim 11.

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