CN111064438A - Analog predistortion circuit, power amplifier and radio frequency module - Google Patents
Analog predistortion circuit, power amplifier and radio frequency module Download PDFInfo
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Abstract
The application discloses an analog predistortion circuit, a power amplifier and a radio frequency module. The analog predistortion circuit includes: the access end receives a radio frequency input signal and is coupled to the input end of the power amplification circuit; a bias terminal for receiving a bias signal; a first inductor, a first end of which is coupled to the access end; a first capacitor adapted to couple a second terminal of the first inductor to a reference ground potential; a nonlinear device, a first end of which is coupled to the bias end and coupled to the access end through a first inductor so as to provide a predistortion signal to the access end, and a second end of which is suitable for providing a regulation current flowing to a reference ground potential; and the second capacitor is coupled between the second end of the nonlinear device and the reference ground potential. The analog predistortion circuit adopts the second capacitor to provide a discharge path from the modulation signal to the reference ground potential, so that the predistortion signal has higher accuracy, and the linearity of the output signal of the power amplifier is improved.
Description
Technical Field
The present invention relates to the field of wireless communication technologies, and in particular, to an analog predistortion circuit, a power amplifier, and a radio frequency module.
Background
In wireless transmission, the attenuation of the signal will affect the transmission distance of the signal. In order to realize the transmission of signals at a longer distance, the signals generally need to be amplified by a power amplifier and then radiated outwards through an antenna, and the power amplifier is mainly used for realizing power amplification so that the signals amplified by the power amplifier have enough power.
In a power amplifier, when the power amplifier is operated in a saturation state, an output signal of the power amplifier generates nonlinear distortion compared with an input signal, and the nonlinear distortion comprises nonlinear amplitude distortion and nonlinear phase distortion. Specifically, the nonlinear distortion is shown in that as the output power of the power amplifier increases, the gain amplitude of the power amplifier decreases nonlinearly, and the gain phase compresses or expands nonlinearly. The nonlinear distortion of the power amplifier can bring adverse factors such as major frequency higher harmonics, intermodulation distortion, broadband spurious and the like, which can adversely affect the signal transmission and reduce the overall performance of the communication system. In order to compensate for the non-linear predistortion of a power amplifier, a predistortion circuit is typically incorporated at the input of the power amplifier to provide a predistortion signal that is opposite to the non-linear distortion, thereby linearizing the output signal of the power amplifier.
However, since the input signal of the power amplifier and the predistortion circuit are coupled to the input terminal of the power amplifier, the input signal of the power amplifier may generate a certain interference to the predistortion signal, and therefore, the predistortion signal generated by the predistortion circuit of the prior art still has a certain error, so that the output signal of the power amplifier still has a certain degree of nonlinear distortion. Therefore, in order to meet the market demand, it is desirable to provide a predistortion circuit with further improvement, so as to reduce the interference of the input signal to the predistortion signal as much as possible, so as to reduce the nonlinear distortion of the power amplifier and improve the linearity of the output signal of the power amplifier.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide an analog predistortion circuit, a power amplifier and a radio frequency module, which can reduce the nonlinear distortion of the power amplifier and improve the linearity of the output signal of the power amplifier.
According to a first aspect of embodiments of the present invention, there is provided an analog predistortion circuit, comprising: the access end receives a radio frequency input signal and is coupled to the input end of the power amplification circuit; a bias terminal for receiving a bias signal; a first inductor having a first end coupled to the access end; a first capacitor adapted to couple a second terminal of the first inductor to a reference ground potential; a nonlinear device, a first end of which is coupled to the bias terminal and coupled to the access terminal through the first inductor to provide a predistortion signal to the access terminal, and a second end of which is adapted to provide a regulated current flowing to a reference ground potential; and the second capacitor is coupled between the second end of the nonlinear device and the reference ground potential.
Preferably, the second terminal of the nonlinear device is coupled to a reference ground potential via a first resistor.
Preferably, the first resistor is an adjustable resistor adapted to configure the phase and/or amplitude of the predistortion signal.
Preferably, the bias terminal is coupled to the access terminal, and the analog predistortion circuit further comprises: and the bias resistor is coupled between the bias end and the access end.
Preferably, the bias terminal is coupled between a first terminal of the nonlinear device and a second terminal of the first inductor.
Preferably, the method further comprises the following steps: a third resistance and a second inductance coupled in series between the first terminal of the nonlinear device and the bias terminal; and a third capacitor coupled between the bias terminal and a reference ground potential.
Preferably, the non-linear device is a bipolar transistor, a field effect transistor or a diode.
Preferably, when the non-linear device is the bipolar transistor or the field effect transistor, a first terminal thereof receives the bias signal, and a bias terminal thereof is coupled to the first terminal thereof; when the nonlinear device is the diode, the anode of the diode receives the bias signal, and the cathode of the diode is coupled to a reference ground potential.
According to a second aspect of embodiments of the present invention, there is provided a power amplifier, comprising: an analog predistortion circuit as described above adapted to provide a predistortion signal; and a power amplification circuit, an input end of which is coupled to the analog predistortion circuit, and receives an input signal and the predistortion signal, and is adapted to perform power amplification on the input signal to obtain a power amplification signal, wherein the predistortion signal is configured to linearize the power amplification signal.
According to a third aspect of embodiments of the present invention, there is provided a radio frequency module including the power amplifier as described above.
According to the analog predistortion circuit, the power amplifier and the radio frequency module, the capacitor coupled to the nonlinear device is adopted to provide a discharge path from the modulation signal to the reference ground potential, so that the predistortion signal generated by the analog predistortion circuit has higher accuracy, the nonlinear distortion of the power amplifier is reduced, and the linearity of the output signal of the power amplifier is improved.
In an optional embodiment, a power supply terminal of the analog predistortion circuit provided by the embodiment of the invention is coupled between the first terminal of the nonlinear device and the second terminal of the first inductor, so that the circuit structure can be simplified, and the cost can be reduced.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.
Fig. 1 shows a schematic diagram of intermodulation distortion of an output signal of a power amplifier.
Fig. 2 shows a schematic structural diagram of a power amplifier according to an embodiment of the invention.
Fig. 3 shows a circuit diagram of a power amplifier according to a first embodiment of the invention.
Fig. 4 shows a circuit diagram of a power amplifier according to a second embodiment of the invention.
Fig. 5a shows a graph of equivalent capacitance of a non-linear device according to an embodiment of the invention.
Figure 5b shows a current-voltage characteristic of the equivalent resistance of a non-linear device according to an embodiment of the invention.
Fig. 6a is a diagram illustrating the relationship between the output power of a power amplifier and the third order intermodulation distortion power according to an embodiment of the present invention.
Fig. 6b is a diagram illustrating the relationship between the output power of the power amplifier and the power of the fifth-order intermodulation distortion according to the embodiment of the present invention.
Fig. 7 shows a schematic block diagram of a radio frequency module of an embodiment of the invention.
List of reference numerals
100 power amplifier
101 input terminal
102 power supply terminal
103 output terminal
104 bias terminal
110 input matching circuit
120 power amplifying circuit
130 output matching circuit
140 analog predistortion circuit
Detailed Description
The invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale. Moreover, certain well-known elements may not be shown in the figures.
In the following description, numerous specific details of the invention, such as structure, materials, dimensions, processing techniques and techniques of the devices are described in order to provide a more thorough understanding of the invention. However, as will be understood by those skilled in the art, the present invention may be practiced without these specific details.
It should be understood that coupling/coupling between a and B in the embodiments of the present application means that a and B may be coupled in series or in parallel, or a and B may be coupled through other devices, which is not limited in the embodiments of the present application.
The power amplifier and the analog predistortion circuit thereof provided by the application can be applied to radio frequency modules of transmitting ends in various communication systems, such as radar equipment, communication equipment, navigation equipment, satellite ground stations, electronic countermeasure equipment and the like. The communication system is, for example but not limited to: a global system for mobile communications (GSM) system, a Code Division Multiple Access (CDMA) system, a Wideband Code Division Multiple Access (WCDMA) system, a General Packet Radio Service (GPRS), a long term evolution (long term evolution, LTE) system, a Frequency Division Duplex (FDD) system, a Time Division Duplex (TDD) system, a universal mobile telecommunications system (universal mobile telecommunications system, UMTS), a Worldwide Interoperability for Microwave Access (WiMAX) communication system, a Wireless Local Area Network (WLAN), a fifth-generation wireless communication system, and the like.
The main function of the power amplifier is to amplify a low power signal generated by a preceding stage circuit to obtain an output signal with sufficient power, which is radiated outward via an antenna and can be transmitted over a sufficiently long distance. As an example, the power amplifier may convert power of a power supply into a current varying according to an input signal by using a current control function of a Bipolar Junction Transistor (BJT for short, also referred to as a triode) or a voltage control function of a Field Effect Transistor (FET for short), thereby performing a current-voltage amplification function.
When the power amplifier performs power amplification on two signals, the two signals are in a linear system, so that a second harmonic of one signal is beat (mixed) with a fundamental wave of the other signal to generate a parasitic signal, which is called a Third Order Intermodulation distortion signal (IMD 3), and similarly, a second harmonic of one signal is beat (mixed) with a Third harmonic of the other signal to generate a parasitic signal, which is called a Fifth Order Intermodulation distortion signal (IMD 5).
Referring to fig. 1, fig. 1 shows a low-frequency signal f in a broadband signalLAnd a high frequency signal fHWhen the power amplifier is used for low-frequency signal fLAnd a high frequency signal fHWhen power amplification is carried out, a third-order intermodulation distortion signal IMD3 is generatedLAnd IMD3HAnd a fifth order intermodulation distortion signal IMD5LAnd IMD5HAt a frequency of 2fL-fH、2fH-fL、3fL-2fHAnd 3fH-2fL。
The third order intermodulation distortion and the fifth order intermodulation distortion have a more significant effect on the linearity of the power amplifier than the higher order intermodulation distortion, the lower the third order intermodulation distortion and the fifth order intermodulation distortion, the better the linearity characterizing the power amplifier.
The power amplifier provided by the embodiment of the invention filters the radio frequency input signal in the analog predistortion circuit and further filters the modulation signal generated after filtering, thereby improving the accuracy of the analog predistortion signal and ensuring the high linearity of the output signal.
Embodiments of the power amplifier provided in the present application will be described below with reference to the accompanying drawings.
Fig. 2 shows a schematic structural diagram of a power amplifier according to an embodiment of the invention.
It should be understood that the power amplifier 100 in the embodiment of the present application may be applied to a Doherty power amplifier architecture, an Outphasing (Outphasing) amplifier, an envelope tracking amplifier, or other power amplifier architectures, which is not limited in the embodiment of the present application.
As shown in fig. 2, a power amplifier 100 according to an embodiment of the present invention includes: an input matching circuit 110, a Power Amplifier (PA) 120, an output matching circuit 130, and an analog predistortion circuit 140.
The input terminal 101 is configured to receive a radio frequency input signal RF _ in, which is, for example, a radio frequency signal. The input matching circuit 110 is coupled between the input terminal 101 and the power amplifying circuit 120 to realize impedance matching between the power amplifying circuit 120 and the input terminal 101. In some alternative embodiments, the input matching circuit 110 may be omitted.
The power supply terminal 102 receives a power supply voltage V provided by a power supplyCC. The supply voltage VCCMay be a voltage provided by a power supply circuit within the power amplifier 100 or a voltage provided by a power supply circuit in the radio frequency module in which the power amplifier 100 is located. In other embodiments, not shown, the supply voltage VCCIt may also be the access voltage V received by the power amplifier 100DDThis is not limited by the present application.
The input node a of the power amplifier circuit 120 is coupled to the input terminal 101 (or coupled to the output node of the input matching circuit 110), and is configured to power-amplify the radio frequency input signal RF _ in received by the input terminal 101 (or the radio frequency input signal RF _ in transmitted to the power amplifier circuit 120 by the input matching circuit 110) to obtain a power amplified signal out _ p, and provide the power amplified signal out _ p to the output matching circuit 130. The power amplifying circuit 120 includes at least a power transistor PA (see fig. 3), which is, for example, a bipolar transistor, a field effect transistor or other type of transistor, and may be equivalent to a controlled current source or voltage source, for converting the energy without information provided by the power supply into the output energy with useful information according to the radio frequency input signal RF _ in, so as to output the power amplifying signal out _ p satisfying the power index.
As an example, an emitter of a bipolar transistor for implementing the power transistor PA may be coupled to a ground reference, a collector of the bipolar transistor may be coupled to the power supply terminal 102 via the output matching circuit 130 to receive energy provided by the power supply, a base of the bipolar transistor may be coupled to the input terminal 101 to receive the RF input signal RF _ in, so that the power transistor PA may be equivalent to a current source controlled by the RF input signal RF _ in and providing a current flowing to the ground reference, a parasitic capacitor connected in parallel with the current source, and the like, and the collector of the power transistor PA provides the power amplifying signal out _ p.
Similarly, as another example, the source of the fet for implementing the power transistor PA may be coupled to a ground reference, the substrate is coupled to the source, the drain may be coupled to the power supply terminal 102 via the output matching circuit 130 to receive the energy provided by the power supply, the gate may be coupled to the input terminal 101 to receive the RF input signal RF _ in, so that the power transistor PA may be equivalent to a current source controlled by the RF input signal RF _ in and providing a current flowing to the ground reference, a drain-source parasitic capacitance connected in parallel with the current source, and the like, and the drain of the power transistor PA provides the power amplifying signal out _ p.
The output matching circuit 130 is coupled between the output node B of the power amplifying circuit 120 and the output terminal 104, obtains the RF output signal RF _ out that can be provided to the output terminal 104 according to the power amplified signal out _ p, and controls the fundamental component and the subharmonic components of the power amplified signal out _ p by configuring the impedance of the fundamental component and the impedance of the subharmonic components (mainly the second harmonic component and the third harmonic component, and may also include higher harmonic components) directed from the output node to the output matching circuit 130 (i.e., to the output terminal 104), so as to improve the efficiency of the power amplifier 100 while satisfying the requirements of linearity, output power, and operating bandwidth, and also enable the power amplifier 100 to be applied to a wider frequency band under the condition of satisfying the linearity index and efficiency requirements. In designing a power amplifier, it is critical to design the output matching circuit 130 properly to improve efficiency, output power, linearity, operating bandwidth, and gain.
The output terminal 103 is used for coupling the output matching circuit 130 to a load of the power amplifier 100, thereby outputting the radio frequency output signal RF _ out to the load. The load of the power amplifier 100 is, for example but not limited to: transmission line, next amplifier, antenna feeder and/or duplexer.
In this embodiment, an analog predistortion circuit 140 is also coupled to the input node a of the power amplification circuit 120. The analog predistortion circuit 140 has an input terminal connected to the input node a of the power amplifying circuit 120, and the analog predistortion circuit 140 further has a Bias terminal 104 for receiving the Bias signal Bias. The analog predistortion circuit 140 is used for providing a predistortion signal pd according to the Bias signal Bias to compensate the nonlinear distortion of the power amplification circuit 120. The predistortion signal pd of the analog predistortion circuit 140 exhibits gain expansion and phase lag characteristics with increasing input power, and can be used to supplement the nonlinear distortion of the power amplifier circuit 120 at saturation power, thereby improving the linearity of the output signal of the power amplifier circuit 120. The phase and amplitude of the predistortion signal pd can be controlled by controlling the magnitude of the Bias signal Bias, so that adaptive compensation can be performed on the power amplification circuits 120 with different output powers.
The analog predistortion circuit 140 provided by the present application will be described in detail below.
Fig. 3 shows a circuit diagram of a power amplifier according to a first embodiment of the invention; fig. 4 shows a circuit diagram of a power amplifier according to a second embodiment of the invention.
As shown in fig. 3, the power amplifier 100 includes an input matching circuit 110, a power amplifying circuit 120, an output matching circuit 130, and an analog predistortion circuit 140, in this embodiment, the input matching circuit 110 is, for example, a capacitor CinThe power amplifier circuit 120 is a bipolar transistor or a field effect transistor, and the output matching circuit 130 is a capacitor C, for exampleoutFor the detailed connection relationship, please refer to fig. 1, which is not described herein.
In this embodiment, the analog predistortion circuit 140 includes at least an inductor LRFCapacitor CRFNonlinear device PD and capacitor CV。
Inductor LRFProvides an input of the analog predistortion circuit 140 and is coupled to the input node a of the power amplification circuit 120 to provide the predistortion signal pd to the power amplification circuit 120. Capacitor CRFCoupled to the inductor LRFAnd a reference ground potential for providing a discharge path between the radio frequency input signal RF _ in to the reference ground potential. Inductor LRFAnd a capacitor CRFTogether forming a filtering circuit for filtering the ac voltage through the dc voltage to provide the dc voltage and the modulated signal to the non-linear device PD.
The first terminal of the non-linear device PD is coupled to the inductor LRFAnd receives a Bias signal Bias provided by the Bias terminal 104, and a second terminal thereof is coupled to the reference ground and provides a regulated current flowing to the reference ground. The nonlinear device PD is adapted to provide a predistortion signal PD according to the Bias signal Bias, the predistortion signal PD being via an inductance LRFIs input to the input node a of the power amplifier circuit 120, the magnitude of which is related to the magnitude of the regulated current flowing to the reference ground potential. The predistortion signal PD of the analog predistortion circuit 140 due to the variable characteristic of the equivalent resistance value of the nonlinear device PDThe characteristics of gain expansion and phase lag exhibited by the increase of the input power can be used to supplement the non-linear distortion of the power amplifier circuit 120 at the saturation power, thereby improving the linearity of the output signal of the power amplifier circuit 120.
Specifically, the nonlinear device PD of the analog predistortion circuit 140 generates different equivalent resistors and equivalent capacitors according to a preset voltage value or current value, thereby providing the amplitude and phase of the desired predistortion signal. For example, referring to fig. 5a and 5b, when the voltage value of the Bias signal Bias received by the nonlinear device PD becomes larger, the equivalent capacitance value thereof becomes smaller, the phase and/or amplitude of the rf input signal can be adjusted, and the equivalent resistance value thereof becomes smaller, the amplitude of the rf input signal can be adjusted.
Optionally, the nonlinear device PD is a bipolar transistor, a field effect transistor, or a diode. When the non-linear device PD is a bipolar transistor or a field effect transistor, its first terminal receives the Bias signal Bias, and its Bias terminal is coupled to its first terminal. When the nonlinear device PD is a diode, the anode of the diode receives the Bias signal Bias, and the cathode of the diode is coupled to the ground reference.
In the embodiment of the invention, the second end of the non-linear device PD is connected with the resistor RVA resistor R coupled to a reference ground potentialVThe equivalent resistance value of the nonlinear device PD is suitable to be configured. Optionally, a resistor RVThe phase and/or amplitude of the predistortion signal pd is adapted to be configured as an adjustable resistor.
In a conventional power amplifier design, since an output terminal of a predistortion circuit is coupled to an input node of a power amplification circuit, a radio frequency input signal at the input node is transmitted to the predistortion circuit, but even if an inductor, a capacitor and other elements are provided in front of a nonlinear device to filter the radio frequency input signal, a part of an alternating voltage flows to the nonlinear device, the part of the alternating voltage is a modulation signal, and the modulation signal interferes with a fed-back predistortion signal, so that the predistortion signal output by the nonlinear device is mixed with unnecessary nonlinear distortion. The embodiment of the application needs to provide a discharge path for a modulation signal entering a nonlinear device to avoid interference of modulation signal feedback on a predistortion signal, so that the linearity of a radio frequency output signal of a power amplifier can be improved.
Therefore, the capacitor C of the embodiment of the inventionVCoupled to the second terminal of the predistortion element PD, is adapted to provide a discharge path for the modulated signal to the reference ground potential. In a power amplifier, Video Bandwidth (VBW) is an important indicator, and the Bandwidth of the power amplifier is usually limited by VBW. Optionally, a capacitor CVThe capacitance value of (c) may be selected based on the video frequency for providing a short circuit ground path at the video frequency. Optionally, a resistor RVThe resistance value of (a) can also be selected according to the video frequency.
As an example, as shown in FIG. 3, the bias terminal 104 is via a bias resistor RBIs coupled to the inductor LRFTo provide a Bias signal Bias to the non-linear device PD. In this example, a bias resistor RBAdapted to provide a bias current. The Bias current and the equivalent resistance value of the nonlinear device PD can be controlled by controlling the magnitude of the Bias signal Bias, and further the phase and amplitude of the predistortion signal PD can be controlled, so that adaptive compensation can be performed on the power amplification circuit 120 with different output powers. The bias terminal 104 receives a voltage V provided by a power supply module (not shown) according to the type of the non-linear device PDgg/VBB. In this example, the offset terminal 104 and the inductor L may be further includedRFAn inductor and an additional resistor are coupled in series therebetween, or a capacitor is coupled between the bias terminal 104 and a reference ground potential, to improve the stability of the circuit.
As another example, as shown in FIG. 4, the bias terminal 104 is coupled to the first terminal of the non-linear device PD, and the bias resistor R may be omittedB. Optionally, an inductance L is coupled in series between the bias terminal 104 and the first terminal of the nonlinear device PDDCAnd a resistance RDCA capacitor C is coupled between the bias terminal 104 and a ground reference potentialV2To improve the stability of the circuit.
Some examples of the power amplifier of the embodiment of the present invention are described above, however, the embodiment of the present invention is not limited thereto, and there may be other extensions and modifications.
For example, it should be understood that the reference ground potential in the foregoing embodiments may be replaced in alternative embodiments with other non-zero reference potentials (having positive or negative voltage magnitudes) or controlled varying reference signals.
For another example, the inductors and the capacitors provided in the embodiments of the present application may be lumped-parameter capacitor elements and inductor elements, or may be other equivalent elements having functions similar to those of the capacitors and the inductors, where the equivalent structures described herein, such as, but not limited to, microstrip lines, varactors, conductor structures with a certain pattern, and the like, can provide inductive impedance and/or capacitive impedance.
For another example, the power amplifier 100 may be a discrete device, may also be a circuit unit, and may also be combined into a high-efficiency high-linearity broadband power amplifier module. In other implementations, the aforementioned power amplifier circuit 120 may be packaged in a device, and the analog predistortion circuit 140 may be a load line structure at the periphery of the device.
Also, those of ordinary skill in the art will recognize that the various example structures and methods described in connection with the embodiments disclosed herein can be implemented with various configurations or adjustments, with reasonable variations on each structure or structure, but such implementations should not be considered as beyond the scope of the present application. Furthermore, it should be understood that the connection relationship between the various components of the amplifier in the foregoing figures in this application embodiment is an illustrative example, and does not set any limit to this application embodiment.
Fig. 6a is a diagram illustrating the relationship between the output power of a power amplifier and the third order intermodulation distortion power according to an embodiment of the present invention; fig. 6b is a diagram illustrating the relationship between the output power of the power amplifier and the power of the fifth-order intermodulation distortion according to the embodiment of the present invention.
In fig. 6a and 6b, dashed lines represent output power versus intermodulation distortion power of a conventional power amplifier, and solid lines represent output power versus intermodulation distortion power of a power amplifier according to an embodiment of the present invention.
As can be seen from fig. 6a and 6b, in the configuration shown in fig. 2 to 4, the power amplifier greatly reduces the third order intermodulation distortion power and the fifth order intermodulation distortion power at the output power Pout of 20-28dBm, and reduces the distortion by 25dB at the output power Pout of about 27.5dBm, thereby having good linearity at high output power Pout.
It should be noted that, in the above embodiments, only the third-order intermodulation distortion and the fifth-order intermodulation distortion are described, because the third-order intermodulation distortion and the fifth-order intermodulation distortion have a more significant effect on the linearity of the power amplifier than the higher-order intermodulation distortion. In some embodiments not shown, other resonant structures may also be introduced to configure the harmonic impedance and phase corresponding to the higher-order intermodulation distortion, such as the seventh-order intermodulation distortion, so as to implement further precise optimization, which is not described herein again.
Fig. 7 shows a schematic block diagram of a radio frequency module of an embodiment of the invention. As mentioned above, the rf module 10 is applied to the transmitting end in various communication systems, and will not be described in detail herein.
As shown in fig. 7, the radio frequency module 10 includes at least a power amplification circuit 120 and an analog predistortion circuit 140 or at least a power amplifier including the power amplification circuit 120 and the analog predistortion circuit 140. For specific implementation of the power amplifier, the power amplifying circuit 120 and the analog predistortion circuit 140, reference may be made to the description of the foregoing embodiments, and details are not described herein again.
The hardware implementation manner of the rf module 10 may be various, for example, the hardware implementation manner may be implemented by a circuit integrated on the same substrate, or implemented by multiple chips, which is not limited in this embodiment of the present invention.
The rf module 10 may further include a switch/duplexer 160, and the output signal provided by the analog predistortion circuit 140 is fed to an antenna 170 through the switch/duplexer 160 so as to be radiated outward with a power satisfying a requirement. The antenna 170 may include at least one sub-antenna, and different sub-antennas may face different frequency bands, so as to radiate an output signal in a wide frequency range.
Optionally, the rf module 10 may further include a transmitting circuit 150, configured to generate a corresponding analog signal as the input signal according to the specified data, so that the power amplifying circuit 120 may perform power amplification on the input signal to raise the power of the input signal containing the data information to a target level. Further, the rf module 10 may further include a processor for providing the transmission circuit 150 with the specific data to be transmitted.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and their full scope and equivalents.
Claims (10)
1. An analog predistortion circuit, comprising:
the access end receives a radio frequency input signal and is coupled to the input end of the power amplification circuit;
a bias terminal for receiving a bias signal;
a first inductor having a first end coupled to the access end;
a first capacitor adapted to couple a second terminal of the first inductor to a reference ground potential;
a nonlinear device, a first end of which is coupled to the bias terminal and coupled to the access terminal through the first inductor to provide a predistortion signal to the access terminal, and a second end of which is adapted to provide a regulated current flowing to a reference ground potential; and
and the second capacitor is coupled between the second end of the nonlinear device and the reference ground potential.
2. The analog predistortion circuit of claim 1, wherein the second terminal of the nonlinear device is coupled to a reference ground potential via a first resistor.
3. The analog predistortion circuit of claim 2, wherein the first resistor is an adjustable resistor adapted to configure the phase and/or amplitude of the predistortion signal.
4. The analog predistortion circuit of claim 1, wherein the bias terminal is coupled to the access terminal, the analog predistortion circuit further comprising:
and the bias resistor is coupled between the bias end and the access end.
5. The analog predistortion circuit of claim 1, wherein the bias terminal is coupled between a first terminal of the nonlinear device and a second terminal of the first inductor.
6. The analog predistortion circuit of claim 5, further comprising:
a third resistance and a second inductance coupled in series between the first terminal of the nonlinear device and the bias terminal; and
a third capacitor coupled between the bias terminal and a reference ground potential.
7. The analog predistortion circuit of claim 1, wherein the nonlinear device is a bipolar transistor, a field effect transistor or a diode.
8. The analog predistortion circuit of claim 7, wherein when the nonlinear device is the bipolar transistor or the field effect transistor, its first terminal receives the bias signal and its bias terminal is coupled to its first terminal;
when the nonlinear device is the diode, the anode of the diode receives the bias signal, and the cathode of the diode is coupled to a reference ground potential.
9. A power amplifier, comprising:
an analog predistortion circuit as claimed in any one of claims 1 to 8, adapted to provide a predistortion signal; and
a power amplification circuit, an input of which is coupled to the analog predistortion circuit and receives an input signal and the predistortion signal, adapted to power amplify the input signal to obtain a power amplified signal,
wherein the predistortion signal is configured to linearize the power amplification signal.
10. A radio frequency module comprising the power amplifier of claim 9.
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| CN111064438B (en) | 2023-12-08 |
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