CN111064438B - 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 terminal receives the radio frequency input signal and is coupled to the input terminal of the power amplifying circuit; the bias terminal receives a bias signal; a first inductor, a first end of which is coupled with the access end; a first capacitor adapted to couple a second end of the first inductor to a reference ground potential; a nonlinear device having a first end coupled to the bias end and coupled to the access end via a first inductor to provide a predistortion signal to the access end and a second end adapted to provide a regulated current flowing to a reference ground potential; and a second capacitor 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 application relates to the field of wireless communications technologies, and in particular, to an analog predistortion circuit, a power amplifier, and a radio frequency module.
Background
During wireless transmission, the attenuation of the signal will affect the transmission distance of the signal. In order to achieve a signal transmission with a longer distance, the signal is usually required to be amplified by a power amplifier and then radiated outwards through an antenna, where the power amplifier is mainly used for achieving power amplification, so that the signal amplified by the power amplifier has enough power.
In a power amplifier, when the power amplifier is operated in a saturated state, an output signal thereof generates nonlinear distortion, including nonlinear amplitude distortion and nonlinear phase distortion, as compared with an input signal. Specifically, nonlinear distortion is represented by nonlinear reduction in gain amplitude of the power amplifier and nonlinear compression or expansion in gain phase as the output power of the power amplifier increases. The nonlinear distortion of the power amplifier can bring adverse factors such as main frequency higher harmonic wave, intermodulation distortion, broadband spurious and the like, thereby adversely affecting the transmission of signals and reducing the overall performance of the communication system. In order to compensate for the nonlinear predistortion of the power amplifier, a predistortion circuit is generally connected to the input terminal of the power amplifier to provide a predistortion signal, and the predistortion signal is opposite to the nonlinear distortion, so that the output signal of the power amplifier is linearized.
However, since the input end of the power amplifier is coupled with the input signal and the predistortion circuit at the same time, the input signal of the power amplifier can generate a certain interference to the predistortion signal, so that the predistortion signal generated by the predistortion circuit in the prior art still has a certain error, and the output signal of the power amplifier still has a certain degree of nonlinear distortion. Therefore, to meet the market demand, it is desirable to provide a predistortion circuit that is further improved, so as to reduce the interference of the input signal on 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 foregoing, an object of the present application is to provide an analog predistortion circuit, a power amplifier and a radio frequency module, so as to reduce nonlinear distortion of the power amplifier and improve linearity of an output signal of the power amplifier.
According to a first aspect of an embodiment of the present application, there is provided an analog predistortion circuit comprising: the access terminal receives the radio frequency input signal and is coupled to the input terminal of the power amplifying circuit; the bias terminal receives a bias signal; a first inductor, a first end of which is coupled with the access end; a first capacitor adapted to couple a second end of the first inductor to a reference ground potential; a nonlinear device having a first terminal coupled to the bias terminal and coupled to the access terminal via the first inductor to provide a predistortion signal to the access terminal and a second terminal adapted to provide a regulated current to a reference ground potential; and a second capacitor coupled between the second end of the nonlinear device and a reference ground potential.
Preferably, the second end 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: a third resistor and a second inductor coupled in series between the first end of the nonlinear device and the bias end; and a third capacitance coupled between the bias terminal and a reference ground potential.
Preferably, the nonlinear device is a bipolar transistor, a field effect transistor or a diode.
Preferably, when the nonlinear device is the bipolar transistor or the field effect transistor, a first end thereof receives the bias signal, and a bias end thereof is coupled to a first end thereof; when the nonlinear device is the diode, the anode of the diode receives the bias signal, and the cathode is coupled to a reference ground potential.
According to a second aspect of an embodiment of the present application, there is provided a power amplifier including: an analog predistortion circuit as described above adapted to provide a predistortion signal; and a power amplification circuit having an input coupled to the analog predistortion circuit and receiving 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 amplified signal.
According to a third aspect of embodiments of the present application, there is provided a radio frequency module comprising a power amplifier as described above.
According to the analog predistortion circuit, the power amplifier and the radio frequency module provided by the embodiment of the application, the capacitor coupled to the nonlinear device is adopted to provide the 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 alternative embodiment, the power supply terminal of the analog predistortion circuit provided by the embodiment of the application 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 application will become more apparent from the following description of embodiments of the present application 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 diagram of a power amplifier according to an embodiment of the application.
Fig. 3 shows a circuit diagram of a power amplifier according to a first embodiment of the application.
Fig. 4 shows a circuit diagram of a power amplifier according to a second embodiment of the application.
Fig. 5a shows a graph of equivalent capacitance of a nonlinear device according to an embodiment of the present application.
Fig. 5b shows the voltammetric characteristic of the equivalent resistance of a nonlinear device according to an embodiment of the present application.
Fig. 6a shows a schematic diagram of the output power of a power amplifier versus third order intermodulation distortion power according to an embodiment of the present application.
Fig. 6b shows a schematic diagram of the output power of a power amplifier versus the fifth order intermodulation distortion power according to an embodiment of the present application.
Fig. 7 shows a schematic block diagram of a radio frequency module according to an embodiment of the application.
List of reference numerals
100. Power amplifier
101. Input terminal
102. Power supply terminal
103. An output terminal
104. Offset end
110. Input matching circuit
120. Power amplifying circuit
130. Output matching circuit
140. Analog predistortion circuit
Detailed Description
The application will be described in more detail below with reference to the accompanying drawings. Like elements are denoted by like reference numerals throughout the various figures. For clarity, the various features of the drawings are not drawn to scale. Furthermore, some well-known portions may not be shown in the drawings.
Numerous specific details of the application, such as device structures, materials, dimensions, processing techniques and technologies, are set forth in the following description in order to provide a thorough understanding of the application. However, as will be understood by those skilled in the art, the present application may be practiced without these specific details.
It should be understood that the connection/coupling between a and B in the embodiments of the present application means that a and B may be coupled in series or parallel, or that a and B may be coupled by 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. Among them, the communication system is, for example but not limited to: global system for mobile communications (global system of mobile communication, GSM), code division multiple access (code division multiple access, CDMA) system, wideband code division multiple access (wideband code division multiple access, WCDMA) system, general packet radio service (general packet radio service, GPRS), long term evolution (long term evolution, LTE) system, LTE frequency division duplex (frequency division duplex, FDD) system, LTE time division duplex (time division duplex, TDD), universal mobile telecommunications system (universal mobile telecommunication system, UMTS), worldwide interoperability for microwave access (worldwide interoperability for microwave access, wiMAX) communication system, wireless local area network (wireless local area network, WLAN), fifth generation wireless communication system, and the like.
The main function of the power amplifier is to amplify a low-power signal generated by the pre-stage circuit to obtain an output signal with sufficient power to radiate outwards through the antenna and to be able to transmit a sufficient distance. As an example, the power amplifier may convert the power of the power supply into a current varying according to an input signal using a current control function of a bipolar transistor (Bipolar Junction Transistor, abbreviated as BJT, also referred to as triode) or a voltage control function of a field effect transistor (Field Effect Transistor, abbreviated as FET), thereby playing a role of current-voltage amplification.
When the power amplifier amplifies power of two signals, the two signals are in a linear system, so that parasitic signals are generated after the second harmonic of one signal and the fundamental wave of the other signal are beaten (mixed), the parasitic signals are called third-order intermodulation distortion signals (Third Order Intermodulation, abbreviated as IMD 3), and similarly, the parasitic signals generated after the second harmonic of one signal and the third harmonic of the other signal are beaten (mixed) are called fifth-order intermodulation distortion signals (Fifth Order Intermodulation, abbreviated as IMD 5).
Referring to FIG. 1, a low frequency signal f in a wide frequency signal is shown in FIG. 1 L And a high frequency signal f H When the power amplifier is to low frequency signal f L And a high frequency signal f H When power amplification is performed, a third-order intermodulation distortion signal IMD3 is generated L And IMD3 H Five-order intermodulation distortion signal IMD5 L And IMD5 H The frequencies are respectively 2f L -f H 、2f H -f L 、3f L -2f H And 3f H -2f L 。
The influence of the third-order intermodulation distortion and the fifth-order intermodulation distortion on the linearity of the power amplifier is more remarkable compared with higher intermodulation distortion, and the lower the third-order intermodulation distortion and the fifth-order intermodulation distortion are, the better the linearity of the power amplifier is represented.
According to the power amplifier provided by the embodiment of the application, the radio frequency input signal in the analog predistortion circuit is filtered, and the modulation signal generated after the filtering is further filtered, so that the accuracy of the analog predistortion signal is improved, and the high linearity of the output signal is ensured.
Embodiments of the power amplifier provided by the present application will be described below with reference to the accompanying drawings.
Fig. 2 shows a schematic diagram of a power amplifier according to an embodiment of the application.
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, etc. power amplifier architectures, or other power amplifier architectures, which is not limited in this embodiment of the present application.
As shown in fig. 2, the power amplifier 100 of the embodiment of the present application includes: an input matching circuit 110, a Power Amplifier (PA) 120, an output matching circuit 130, and an analog predistortion circuit 140.
The input 101 is configured to receive a radio frequency input signal rf_in, 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 achieve 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 supply CC . The supply voltage V CC May be the voltage provided by the power supply circuitry within the power amplifier 100 or the voltage provided by the power supply circuitry in the radio frequency module in which the power amplifier 100 is located. In other embodiments, not shown, the supply voltage V CC It may also be the access voltage V received by the power amplifier 100 DD The application is not limited in this regard.
The input node a of the power amplifying 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 amplifying 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 at least comprises a power transistor PA (see fig. 3), which is, for example, a bipolar transistor, a field effect transistor or another type of transistor, and may be equivalently, a controlled current source or a voltage source, for converting the energy provided by the power supply and not containing information into the output energy containing useful information according to the radio frequency input signal rf_in, so as to output the power amplifying signal out_p meeting the power index.
As an example, the emitter of the bipolar transistor used to implement the power tube PA may be coupled to the reference ground potential, the collector is coupled to the power supply terminal 102 via the output matching circuit 130 to receive the energy provided by the power supply, the base may be coupled to the input terminal 101 to receive the radio frequency input signal rf_in, so that the power tube PA may be equivalently a current source controlled by the radio frequency input signal rf_in and providing a current flowing to the reference ground potential, a parasitic capacitance connected in parallel with the current source, and the like, and the collector of the power tube PA provides the power amplification signal out_p.
Similarly, as another example, a source of a field effect transistor for implementing the power tube PA may be coupled to the reference ground potential, a substrate is coupled to the source, a drain may be coupled to the power supply terminal 102 via the output matching circuit 130 to receive energy provided by the power supply, and a gate may be coupled to the input terminal 101 to receive the radio frequency input signal rf_in, so that the power tube PA may be equivalently a current source controlled by the radio frequency input signal rf_in and providing a current flowing to the reference ground potential, a drain-source parasitic capacitance connected in parallel with the current source, and the like, and a drain of the power tube PA provides the power amplification 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, and obtains a radio frequency output signal rf_out that can be provided to the output terminal 104 according to the power amplifying signal out_p, and by configuring the impedance of the fundamental component, each harmonic component (mainly the second harmonic component and the third harmonic component, and may also include the higher harmonic component) directed to the output matching circuit 130 (i.e. directed to the output terminal 104) by the output node, the control of the fundamental component and each harmonic component of the power amplifying signal out_p is achieved, so as to improve the efficiency of the power amplifier 100 while meeting the requirements of linearity, output power and operating bandwidth, and also enable the power amplifier 100 to be applied to a wider frequency band while meeting the requirements of linearity index and efficiency. In designing a power amplifier, the rational design of the output matching circuit 130 is critical to improving efficiency, output power, linearity, operating bandwidth, and gain.
The output terminal 103 is used for coupling the output matching circuit 130 to the load of the power amplifier 100, so as to output the radio frequency output signal rf_out to the load. The load of the power amplifier 100 is, for example and without limitation: transmission line, next-stage 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 and is connected to the input node a of the power amplification circuit 120 via the input terminal, and the analog predistortion circuit 140 further has a Bias terminal 104 for receiving the Bias signal Bias. The analog predistortion circuit 140 is configured to provide a predistortion signal pd according to the Bias signal Bias to compensate for nonlinear distortion of the power amplification circuit 120. The predistortion signal pd of the analog predistortion circuit 140 exhibits characteristics of gain expansion and phase lag with increasing input power, and can be used to supplement nonlinear distortion of the power amplification circuit 120 at saturated power, thereby improving output signal linearity of the power amplification 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 the power amplifying circuit 120 with different output powers can be adaptively compensated.
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 application; fig. 4 shows a circuit diagram of a power amplifier according to a second embodiment of the application.
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 C in The power amplifier circuit 120 is a bipolar transistor or a field effect transistor, and the output matching circuit 130 is a capacitor C out The specific connection relationship is shown in fig. 1, and will not be described herein.
In this embodiment, the analog predistortion circuit 140 includes at least an inductance L RF Capacitance C RF Nonlinear device PD and capacitor C V 。
Inductance L RF An access terminal of the analog predistortion circuit 140 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 C RF Coupled to the inductor L RF For providing a discharge path between the radio frequency input signal RF in to the reference ground potential. Inductance L RF And capacitor C RF Together, a filter circuit for filtering the alternating voltage, through the direct voltage, is formed to provide the direct voltage and the modulation signal to the nonlinear device PD.
The first end of the nonlinear device PD is coupled to the inductance L RF And receives Bias signal Bias provided by Bias terminal 104, the second terminal of which is coupled to a reference ground and provides a regulated current to the reference ground. The nonlinear device PD is adapted to provide a predistortion signal PD based on the Bias signal Bias, the predistortion signal PD being via an inductance L RF The first terminal of which is provided to the input node a of the power amplifying circuit 120, which is related to the magnitude of the regulated current flowing to the reference ground potential. Due to the variable characteristic of the equivalent resistance value of the nonlinear device PD, the predistortion signal PD of the analog predistortion circuit 140 exhibits characteristics of gain expansion and phase lag with an increase in input power, and can be used to supplement nonlinear distortion of the power amplification circuit 120 at saturated power, thereby improving output signal linearity of the power amplification circuit 120.
Specifically, the nonlinear device PD of the analog predistortion circuit 140 generates different equivalent resistances and equivalent capacitances according to a preset voltage value or current value, so as to provide the required magnitude and phase of the 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, so that the phase and/or amplitude of the radio frequency input signal can be adjusted, and the equivalent resistance value thereof becomes smaller, so that the amplitude of the radio frequency input signal can be adjusted.
Alternatively, the nonlinear device PD is a bipolar transistor, a field effect transistor or a diode. When the nonlinear 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 positive electrode of the device receives the Bias signal Bias, and the negative electrode is coupled to the reference ground potential.
In the embodiment of the application, the second end of the nonlinear device PD is connected with the resistor R V Coupled to a reference ground potential, resistor R V Is suitable for configuring the equivalent resistance value of the nonlinear device PD. Alternatively, resistance R V For the adjustable resistance, the phase and/or amplitude of the predistortion signal pd is adapted to be configured.
In the conventional power amplifier design, since the output terminal of the predistortion circuit is coupled to the input node of the power amplification circuit, the radio frequency input signal at the input node is transmitted to the predistortion circuit, but even if elements such as an inductor and a capacitor are provided in front of the nonlinear device to filter the radio frequency input signal, a part of the ac voltage flows to the nonlinear element, and the part of the ac voltage is a modulation signal, the modulation signal interferes with the 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 the modulation signal entering the nonlinear device so as to avoid interference of the modulation signal feedback on the predistortion signal, thereby improving the linearity of the radio frequency output signal of the power amplifier.
For this reason, the capacitor C of the embodiment of the application V Is coupled to a second end of the predistortion element PD and is adapted to provide a discharge path for the modulated signal to a reference ground potential. In a power amplifier, video Bandwidth (VBW) is an important indicator, and the Bandwidth of the power amplifier is generally limited to VBW. Alternatively, capacitor C V Can be selected according to the video frequency for providing a short-circuited ground path at the video frequency. Optionally, a resistor R V The resistance value of (2) may also be selected based on the video frequency.
As an example, as shown in fig. 3, bias terminal 104 is via bias resistor R B Coupled to the inductance L RF To a non-linear directionThe sexual device PD provides a Bias signal Bias. In this example, the bias resistor R B Adapted to provide a bias current. The magnitude of the Bias signal Bias can be controlled to control the Bias current and the equivalent resistance value of the nonlinear device PD, and further the phase and amplitude of the predistortion signal PD can be controlled, so that the power amplifying circuit 120 with different output powers can be adaptively compensated. Depending on the type of nonlinear device PD, bias terminal 104 receives a voltage V provided by a power supply module (not shown) gg /V BB . In this example, the inductor L may also be coupled to the bias terminal 104 RF An inductor and an additional resistor are coupled in series, or a capacitor is coupled between the bias terminal 104 and a reference ground 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 nonlinear device PD, and the bias resistor R can be omitted B . Optionally, an inductance L is coupled in series between the bias terminal 104 and the first terminal of the nonlinear device PD DC And resistance R DC A capacitor C is coupled between the bias terminal 104 and the reference ground potential V2 To improve the stability of the circuit.
Some examples of the power amplifier of the embodiment of the present application are described above, however the embodiment of the present application is not limited thereto, and other manners of expansion and modification are also possible.
For example, it should be appreciated that the reference ground potential in the foregoing embodiments may be replaced with other non-zero reference potentials (having positive or negative voltage magnitudes) or controlled varying reference signals in alternative embodiments.
For another example, the inductance and capacitance provided by the embodiment of the application may be lumped parameter capacitance elements and inductance elements, and may also be other equivalent elements with functions similar to those of capacitance and inductance, where the equivalent structures are, for example, but not limited to, microstrip lines, varactors, conductor structures with a certain pattern, and the like, which can provide inductive impedance and/or capacitive impedance.
For another example, the power amplifier 100 may be a discrete device, or may be a circuit unit, or may be combined into a high-efficiency and high-linearity broadband power amplifier module. In other implementations, the power amplification circuit 120 may be packaged in a device, and the analog predistortion circuit 140 may act as a load line structure around the device.
Also, those of ordinary skill in the art will recognize that structures and methods of examples described in connection with the embodiments disclosed herein may be implemented using different configurations or adaptations of each structure or reasonable variations of that structure to achieve the described functionality, but such implementations should not be considered to be beyond the scope of the present application. Also, it should be understood that the connection relationship between the respective components of the amplifier of the foregoing drawings in the embodiments of the present application is illustrative and not limiting in any way.
FIG. 6a is a schematic diagram showing the output power of a power amplifier versus third order intermodulation distortion power according to an embodiment of the present application; fig. 6b shows a schematic diagram of the output power of a power amplifier versus the fifth order intermodulation distortion power according to an embodiment of the present application.
In fig. 6a and 6b, a graph of output power versus intermodulation distortion power of a conventional power amplifier is shown by a dotted line, and a graph of output power versus intermodulation distortion power of a power amplifier according to an embodiment of the present application is shown by a solid line.
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 an output power Pout of 20-28dBm, and reduces the distortion by 25dB at an output power Pout of about 27.5dBm, thus having good linearity at a high output power Pout.
It should be noted that, in the above embodiment, only the third-order intermodulation distortion and the fifth-order intermodulation distortion are described, because the influence of the third-order intermodulation distortion and the fifth-order intermodulation distortion on the linearity of the power amplifier is more remarkable than the higher-order intermodulation distortion. In some embodiments, which are not shown, other resonant structures may be introduced to configure harmonic impedance and phase corresponding to higher intermodulation distortion such as seventh order intermodulation distortion, so as to achieve further accurate optimization, which is not described herein.
Fig. 7 shows a schematic block diagram of a radio frequency module according to an embodiment of the application. As described above, the rf module 10 is used at the transmitting end in various communication systems, and will not be described herein.
As shown in fig. 7, the radio frequency module 10 includes at least a power amplifying circuit 120 and an analog predistortion circuit 140 or includes at least a power amplifier including the power amplifying circuit 120 and the analog predistortion circuit 140. The specific implementation of the power amplifier, the power amplifying circuit 120 and the analog predistortion circuit 140 may be referred to the description of the above embodiments, and will not be repeated here.
The hardware implementation of the rf module 10 may be various, for example, may be implemented by a circuit integrated on the same substrate, or may be implemented by multiple chips, which is not limited in this embodiment of the present application.
The radio frequency module 10 may also include a switch/diplexer 160, and the output signal provided by the analog predistortion circuit 140 is fed to the antenna 170 via the switch/diplexer 160 to radiate outward at a power that meets the requirements. The antenna 170 may include at least one sub-antenna, and different sub-antennas may face different frequency bands, thereby being capable of radiating output signals in a wide frequency range.
Optionally, the radio frequency module 10 may further include a transmitting circuit 150 for generating a corresponding analog signal as the input signal according to the foregoing embodiment according to the specified data, so that the power amplifying circuit 120 may power amplify the input signal to raise the power of the input signal containing the data information to the target level. Further, the radio frequency module 10 may further include a processor for providing the transmitting circuit 150 with the designated data to be transmitted.
It should be noted that in this document relational terms such as first and second, and the like are 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. Moreover, 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 one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
Embodiments in accordance with the present application, as described above, are not intended to be exhaustive or to limit the application to the precise embodiments disclosed. 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 application and the practical application, to thereby enable others skilled in the art to best utilize the application and various modifications as are suited to the particular use contemplated. The application is limited only by the claims and the full scope and equivalents thereof.
Claims (10)
1. An analog predistortion circuit, comprising:
the access terminal receives the radio frequency input signal and is coupled to the input terminal of the power amplifying circuit;
the bias terminal receives a bias signal;
a first inductor, a first end of which is coupled with the access end;
a first capacitor adapted to couple a second end of the first inductor to a reference ground potential;
a nonlinear device having a first terminal coupled to the bias terminal and coupled to the access terminal via the first inductor to provide a predistortion signal to the access terminal and a second terminal adapted to provide a regulated current to a reference ground potential; and
a second capacitor coupled between a second end of the nonlinear device and a reference ground potential,
and the second capacitor is connected to the current output end of the nonlinear device so as to provide a discharge path between the modulation signal and the reference ground potential.
2. An analog predistortion circuit according to claim 1, wherein the second terminal of the nonlinear device is coupled to a reference ground potential via a first resistor.
3. An analog predistortion circuit according to 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 said bias terminal is coupled to said access terminal, said 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 said bias terminal is coupled between a first terminal of said nonlinear device and a second terminal of said first inductor.
6. The analog predistortion circuit of claim 5, further comprising:
a third resistor and a second inductor coupled in series between the first end of the nonlinear device and the bias end; and
and a third capacitor coupled between the bias terminal and a reference ground potential.
7. An analog predistortion circuit according to 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 said nonlinear device is said bipolar transistor or said field effect transistor, a first terminal thereof receives said bias signal and a bias terminal thereof is coupled to a first terminal thereof;
when the nonlinear device is the diode, the anode of the diode receives the bias signal, and the cathode 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 amplifying circuit having an input coupled to the analog predistortion circuit and receiving 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 amplified signal.
10. A radio frequency module comprising the power amplifier of claim 9.
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