Abstract:
A method and apparatus are disclosed for a configurable amplifier. When operating in a first operating mode, the configurable amplifier may amplify a communication signal and may cancel or attenuate a second harmonic component associated with the communication signal. When operating in a second operating mode, the configurable amplifier may amplify the communication signal without cancelling or attenuating the second harmonic component associated with the communication signal.

Description:
TECHNICAL FIELD 
     The present embodiments relate generally to communication devices, and specifically to amplifiers within communication devices that may amplify a signal while reducing harmonic distortion. 
     BACKGROUND OF RELATED ART 
     Communication devices may transmit and receive communication data through a communication medium. In one example, the communication medium may be a wireless communication medium where communication data is transmitted and received by communication devices according to a wireless communication protocol. Example wireless communication protocols may include IEEE 802.11 protocols and Bluetooth protocols according to the Bluetooth Special Interest Group. In another example, the communication medium may be a wired communication medium where the communication data is transmitted and received according to a wire-based communication protocol. Some example wire-based protocols may include an Ethernet® protocol and/or a Powerline Communications protocol described by the HomePlug 2.0 specification. In yet another example, the communication medium may be a hybrid combination of wired and wireless communication mediums. 
     Analog signals within communication devices may undergo amplification during various processing operations. For example, an analog signal may be amplified when a communication signal is received from or transmitted to another communication device. In some cases, as an analog signal is amplified, an unwanted signal may be introduced (e.g., added) to the amplified signal. For example, as a first signal is amplified, a second signal that is an unwanted harmonic of the first signal may also be amplified. The unwanted signal may distort the amplified signal, reducing the accuracy of the amplified signal and increasing the difficulty of receiving the amplified signal and decoding the data within the amplified signal. In some cases, the unwanted signal may couple into a sensitive receive and/or transmit circuit and interfere with the transmission and/or reception of the communication data. 
     Thus, there is a need to improve the amplification of analog signals while suppressing amplification of unwanted signals, and thereby improve the performance of the communication device. 
     SUMMARY 
     This Summary is provided to introduce in a simplified form a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter. 
     A configurable amplifier and method of operation are disclosed. The configurable amplifier may amplify a communication signal while cancelling or attenuating a second harmonic component of the communication signal. In one embodiment, the configurable amplifier may include a first processing chain to generate a first up-converted communication signal, a second processing chain to generate a second up-converted communication signal, and a summing node to generate an output signal of the configurable amplifier based, at least in part, on the first up-converted communication signal and the second up-converted communication signal. When the configurable amplifier is to operate in a first mode, the second up-converted communication signal is a substantially ninety degree phase-shifted version of the first up-converted communication signal. When the configurable amplifier is to operate in a second mode, the second up-converted communication signal is substantially similar to the first up-converted communication signal. 
     A wireless communication device is disclosed. The wireless communication device may include a baseband processor and a configurable amplifier, coupled to the baseband processor, to amplify communication signals, the configurable amplifier including: a first processing chain to generate a first up-converted communication signal, a second processing chain to generate a second up-converted communication signal, and a summing node to generate an output signal of the configurable amplifier based, at least in part, on the first up-converted communication signal and the second up-converted communication signal. When the configurable amplifier is to operate in a first mode, the second up-converted communication signal is a substantially ninety degree phase-shifted version of the first up-converted communication signal. When the configurable amplifier is to operate in a second mode, the second up-converted communication signal is substantially similar to the first up-converted communication signal. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present embodiments are illustrated by way of example and are not intended to be limited by the figures of the accompanying drawings. Like numbers reference like elements throughout the drawings and specification. 
         FIG. 1  depicts an example communication system within which example embodiments may be implemented. 
         FIG. 2  shows a schematic diagram of a configurable amplifier, in accordance with example embodiments. 
         FIG. 3  is a block diagram of a mode controller, in accordance with example embodiments. 
         FIG. 4  shows a wireless device that is one embodiment of a wireless device of  FIG. 1 . 
         FIG. 5  shows an illustrative flow chart depicting an exemplary operation for operating a configurable amplifier, in accordance with example embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The present embodiments are described below in the context of Wi-Fi enabled devices for simplicity only. It is to be understood that the present embodiments are equally applicable for devices using signals of other various wireless standards or protocols. As used herein, the terms “wireless local area network (WLAN)” and “Wi-Fi” can include communications governed by the IEEE 802.11 standards, BLUETOOTH®, HiperLAN (a set of wireless standards, comparable to the IEEE 802.11 standards, used primarily in Europe), and other technologies used in wireless communications (e.g., ZigBee and WiGig). 
     In the following description, numerous specific details are set forth such as examples of specific components, circuits, and processes to provide a thorough understanding of the present disclosure. The term “coupled” as used herein means coupled directly to or coupled through one or more intervening components or circuits. Also, in the following description and for purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the present embodiments. However, it will be apparent to one skilled in the art that these specific details may not be required to practice the present embodiments. In other instances, well-known circuits and devices are shown in block diagram form to avoid obscuring the present disclosure. Any of the signals provided over various buses described herein may be time-multiplexed with other signals and provided over one or more common buses. Additionally, the interconnection between circuit elements or software blocks may be shown as buses or as single signal lines. Each of the buses may alternatively be a single signal line, and each of the single signal lines may alternatively be buses, and a single line or bus might represent any one or more of a myriad of physical or logical mechanisms for communication between components. The present embodiments are not to be construed as limited to specific examples described herein but rather to include within their scope all embodiments defined by the appended claims. 
       FIG. 1  depicts an example communication system  100  within which example embodiments may be implemented. Communication system  100  may be a wireless system and may include wireless device  102  and wireless device  103 . Although only two wireless devices  102  and  103  are shown for simplicity, communication system  100  may include any number of wireless devices. In other embodiments, communication system  100  may be a wired system and may include wired devices coupled to a wire or cable (not shown for simplicity). In still other embodiments, communication system  100  may be a hybrid system and may include both wireless and wired devices. 
     Wireless device  102  may include a transceiver  120 , a baseband processor  110 , and an antenna  160 . Although not shown for simplicity, wireless device  102  may include a plurality of antennas. Baseband processor  110  may provide data to be transmitted to and/or receive data from one or more other devices via transceiver  120  and antenna  160 . For example, baseband processor  110  may encode and/or decode the communication data for transmission and/or reception by transceiver  120 . 
     Transceiver  120  may include a digital processor  140  and an analog processor  130 . Digital processor  140  may receive the communication data from and provide the communication data to baseband processor  110 . In some embodiments, the communication data may be processed according to a wireless communication protocol such as Wi-Fi, BLUETOOTH, near-field communication, Zig-Bee, or any other feasible wireless communication protocol. In other embodiments, the communication data may be processed according to a wired protocol such as an Ethernet, Powerline Communication (PLC), or any other feasible wired communication protocol. In still other embodiments, the communication data may be processed according to both a wireless and a wired communication protocol. 
     In some embodiments, analog processor  130  may be coupled to digital processor  140  and to antenna  160 . Analog processor  130  may process communication data to and/or from digital processor  140 . For example, analog processor  130  may process communication data from digital processor  140  for transmission through antenna  160  and/or analog processor  130  may process and provide communication data received through antenna  160  to digital processor  140 . 
     Analog processor  130  may include a configurable amplifier  135  to amplify one or more communication signals. For example, configurable amplifier  135  may amplify a communication signal received through antenna  160 . In another example, configurable amplifier  135  may amplify a communication signal to be transmitted from antenna  160 . In some embodiments, configurable amplifier  135  may amplify the communication signal while suppressing unwanted harmonics of the communication signal. Operation of configurable amplifier  135  is described in more detail below in conjunction with  FIG. 2 . 
     Persons skilled in the art will recognize that an output signal of an amplifier, such as configurable amplifier  135 , may be described with a power series of the form shown in eq. 1 below:
 
Output= gm 1( S 1)cos θ+ gm 2( S 1) 2  cos 2   θ+gm 3( S 1) 3  cos 3 θ+ . . .  (eq. 1)
     where: gm(S1)cos θ is a first harmonic of the output signal (e.g., desired signal);
       gm2(S1) 2  cos 2 θ is a second harmonic of the output signal;   gm3(S1) 3  cos 3 θ is a third harmonic of the output signal, and so forth.   
       

     The term “gm” may represent a gain of the amplifier associated with the first harmonic, the term “gm2” may represent a gain of the amplifier associated with the second harmonic, and so forth. The input signal to the amplifier may be represented by the term “(S1)cos θ”. 
     In some embodiments, to reduce effects associated with the second harmonic component (e.g., the second harmonic of the output signal), the output signal may be based on the input signal (S1)cos θ and a version of the input signal shifted by ninety (90) degrees (e.g., (S1)sin θ). Eq. 1 may be rewritten to express the output signal as a function of the input signal (S1)cos θ (e.g., original input signal) and (S1)sin θ (e.g., original input signal shifted by ninety degrees) as shown in eq. 2, below (note: eq. 2 is simplified to only include first and second harmonic terms):
 
Output= gm 1( S 1)cos θ+ gm 2( S 1) 2  cos 2   θ+gm 1( S 1)sin θ+ gm 2( S 1) 2  sin 2 θ   (eq. 2)
 
     Eq. 2 may be rewritten to combine the first harmonic and the second harmonic terms as shown below in eq. 3:
 
Output= gm 1( S 1)cos θ+ gm 1( S 1)sin θ+ gm 2( S 1) 2  cos 2   θ+gm 2( S 1) 2  sin 2 θ   (eq. 3)
 
     Simplifying eq. 3 gives:
 
Output= gm 1( S 1)(cos θ+sin θ)+ gm 2( S 1) 2   (eq. 4)
 
where: gm1(S1)(cos θ+sin θ) is associated with the first harmonic, and
 
     gm2(S1) 2  is associated with the second harmonic. 
     Note that the term associated with the second harmonic component has been simplified to a constant, and thus is no longer dependent on frequency. In other words, signals associated with a second harmonic distortion may be cancelled or substantially reduced when the input signal and a ninety degree shifted version of the input signal are processed at substantially the same time by the amplifier. Note also that the term associated with the first harmonic component has changed from “gm1(S1)cos θ” to “gm1(S1)(cos θ+sin θ),” for example, to indicate a change in the amplitude of the first harmonic component. 
       FIG. 2  shows a schematic diagram of a configurable amplifier  200 , in accordance with example embodiments. Configurable amplifier  200  may be another embodiment of configurable amplifier  135  of  FIG. 1 . Configurable amplifier  200  may include a first processing path P 1  and a second processing path P 2 . First processing path P 1  may include a first mixer  210 , a second mixer  215 , a first buffer  230 , a first summing node  217 , and a first transistor pair  260 . Second processing path P 2  may include a third mixer  220 , a fourth mixer  225 , a first local oscillator (LO) signal selector  245 , a second LO signal selector  246 , a second buffer  235 , a second summing node  227 , and a second transistor pair  261 . The first transistor pair  260  may be coupled to the second transistor pair  261  at a third summing node  241 . 
     First processing path P 1  may generate a first up-converted communication signal  274  and second processing path P 2  may generate a second up-converted communication signal  276 . Third summing node  241  may sum together first up-converted communication signal  274  and second up-converted communication signal  276  to generate a configurable amplifier output signal  275 . 
     Configurable amplifier  200  may operate in a normal mode or in a cancelling mode. When configurable amplifier  200  operates in the normal mode, second up-converted communication signal  276  may be substantially similar to first up-converted communication signal  274 . Thus, when configurable amplifier  200  operates in the normal mode, third summing node  241  may sum together first up-converted communication signal  274  and second up-converted communication signal  276  (substantially similar to the first up-converted communication signal  274 ) to generate configurable amplifier output signal  275 . 
     When configurable amplifier  200  operates in the cancelling mode, second processing path P 2  may generate second up-converted communication signal  276  to be a ninety degree phase-shifted version of first up-converted communication signal  274  generated by first processing path P 1 . Thus, when configurable amplifier  200  operates in the cancelling mode, third summing node  241  may sum together first up-converted communication signal  274  and a ninety degree phase-shifted version of first up-converted communication signal  276 . The resulting summed signal, denoted as configurable amplifier output signal  275 , may have a cancelled or reduced second harmonic distortion (based, at least in part, on eq. 4). 
     Thus, as described in more detail below, when configurable amplifier  200  operates in the cancelling mode, the second up-converted communication signal  276  may cancel at least second-order harmonics of the configurable amplifier output signal  275 ; when configurable amplifier  200  operates in the normal mode, the second up-converted communication signal  276  may increase the magnitude of the configurable amplifier output signal  275  (e.g., as compared to the output signal magnitude when configurable amplifier  200  operates in the cancelling mode). 
     First processing path P 1  may mix together an LO signal and a baseband signal. In some embodiments, the LO signal and the baseband signal may be quadrature signals. For example, the LO signal may include an LO in-phase (I) signal  201  and an LO quadrature (Q) signal  203 . In a similar manner, the baseband signal may include a baseband in-phase (I) signal  202  and a baseband quadrature (Q) signal  204 . First mixer  210  may “mix” (e.g., multiply) together LO (I) signal  201  and baseband (I) signal  202  to generate a first mixer output signal that may be provided to first summing node  217 . In a similar manner, second mixer  215  may mix together LO (Q) signal  203  and baseband (Q) signal  204  to generate a second mixer output signal that may be provided to first summing node  217 . Output signals from first mixer  210  and second mixer  215  may be summed together at first summing node  217 , and the resulting summed signal may be provided to first buffer  230 . 
     First buffer  230  may be coupled to first transistor pair  260 . First transistor pair  260  may amplify and/or buffer output signals from first buffer  230 . First transistor pair  260  may include a first transistor Q 1  and a second transistor Q 2  configured as a cascode pair. In some embodiments, second transistor Q 2  may include a gate terminal coupled to a bias voltage VB 1 . A gate terminal of first transistor Q 1  may receive the output signal provided by first buffer  230 , and a drain terminal of second transistor Q 2  may provide an output signal (e.g., first up-converted communication signal  274 ) from first transistor pair  260  to third summing node  241 . 
     Third summing node  241  may be coupled to output inductor  242 . Output inductor  242  may receive configurable amplifier output signal  275  from third summing node  241 , and output inductor  242  may be coupled to other circuits or devices (not shown for simplicity). For example, output inductor  242  may be coupled to an antenna, a balun, a coupler, or any other technically feasible device. Thus, in some embodiments, configurable amplifier output signal  275  may be provided to other circuits or devices through output inductor  242 . 
     Although depicted with NMOS transistors, other embodiments of first transistor pair  260  may include any other technically feasible transistor types. For example, first transistor Q 1  and/or second transistor Q 2  may be a PMOS, an NPN, and/or a PNP transistor (not shown for simplicity). In still other embodiments, first transistor pair  260  may be replaced with other devices to amplify and/or buffer output signals from first buffer  230  or first summing node  217 . For example, first transistor pair  260  may be replaced with an inverting amplifier, a voltage buffer, a current buffer, an operational amplifier, or any other technically feasible amplifier. 
     In a similar manner, when configurable amplifier  200  operates in the normal mode, second processing path P 2  may also mix together the baseband signal and the LO signal. For example, LO (I) signal  201  may be selected by first LO signal selector  245  and provided to third mixer  220 . First LO signal selector  245  may include switches, transistors, multiplexors, and/or any other technically feasible devices and/or components to select signals, such as LO (I) signal  201 . Third mixer  220  may mix together LO (I) signal  201  and baseband (I) signal  202  and provide a third mixer output signal to second summing node  227 . LO (Q) signal  203  may be selected by second LO signal selector  246  and provided to fourth mixer  225 . Fourth mixer  225  may mix together LO (Q) signal  203  and baseband (Q) signal  204  and provide a fourth mixer output signal to second summing node  227 . Output signals from third mixer  220  and fourth mixer  225  may be summed together at second summing node  227 , and the resulting summed signal may be coupled to second buffer  235 . 
     Second buffer  235  may be coupled to second transistor pair  261 . Second transistor pair  261  may amplify and/or buffer output signals from second buffer  235 . Second transistor pair  261  may include a third transistor Q 3  and a fourth transistor Q 4  configured as a cascode pair. In some embodiments, fourth transistor Q 4  may include a gate terminal coupled to a bias voltage VB 2 . A gate terminal of third transistor Q 3  may receive the output signal from second buffer  235 , and a drain terminal of fourth transistor Q 4  may provide an output signal (e.g., second up-converted communication signal  276 ) from second transistor pair  261  to third summing node  241 . 
     Second up-converted communication signal  276  from second transistor pair  261  may be coupled to third summing node  241 . Thus, third summing node  241  may sum together first up-converted communication signal  274  and second up-converted communication signal  276 , thereby summing together output signals from first processing path P 1  and second processing path P 2 . 
     When configurable amplifier  200  operates in the normal mode, first processing path P 1  and second processing path P 2  may each generate a substantially similar signal that may be summed together at third summing node  241 . For example, the LO signal (including both in-phase and quadrature components) may be expressed by eq., 5 shown below:
 
LO signal=cos α−sin α  (eq. 5)
 
where: −sin α is associated with LO (I) signal  201 ; and
 
     cos α is associated with LO (Q) signal  203 . 
     Thus, the quadrature relationship between LO (I) signal  201  and LO (Q) signal  203  may be expressed by cosine and sine terms in eq. 5. In a similar manner, the baseband signal may be expressed by eq. 6, shown below:
 
baseband signal=sin β+cos β  (eq. 6)
 
where: sin β is associated with baseband (I) signal  202 ; and
 
     cos β is associated with baseband (Q) signal  204 . 
     Thus, the quadrature relationship between baseband (I) signal  202  and baseband (Q) signal  204  may be described by sine and cosine terms in eq. 6. 
     An output signal from first processing path P 1  may be expressed by eq. 7 shown below:
 
output signal  P 1=cos α cos β−sin α sin β  (eq. 7)
     where: cos α cos β is associated with mixing LO (Q) signal  203  together with baseband (Q) signal  204 ; and
       sin α sin β is associated with mixing LO (I) signal  201  together with baseband (I) signal  202 .   
       

     When configurable amplifier  200  operates in the normal mode, first up-converted communication signal  274  and second up-converted communication signal  276  are substantially similar. Since configurable amplifier output signal  275  may be based on a sum of similar output signals from first processing path P 1  and second processing path P 2 , the configurable amplifier output signal  275  may be expressed by eq. 8, shown below:
 
configurable amplifier output signal 275=2(cos α cos β−sin α sin β)  (eq. 8)
 
     Thus, because the first up-converted communication signal  274  and the second up-converted communication signal  276  are substantially similar and are summed at third summing node  241 , the magnitude of the configurable amplifier output signal  275  may be increased relative to the output signal magnitude when configurable amplifier  200  operates in the cancelling mode. 
     As described above in conjunction with eq. 4, a second harmonic component of an output signal may be reduced or canceled by adding together a first signal and a ninety degree phase-shifted version of the first signal. Thus, when configurable amplifier  200  operates in the cancelling mode, second processing path P 2  may be configured to generate second up-converted communication signal  276  to be a ninety degree phase-shifted version of first up-converted communication signal  274  provided by first processing path P 1 . In some embodiments, the LO signal used in second processing path P 2  may be phase-shifted by ninety degrees with respect to the LO signal used in first processing path P 1 . For example, LO (I) signal  201  may be replaced with LO_shifted (I) signal  205 , and LO (Q) signal  203  may be replaced with LO_shifted (Q) signal  206 . In some embodiments, LO_shifted (I) signal  205  and LO_shifted (Q) signal  206  may be ninety degree phase-shifted versions of LO (I) signal  201  and LO (Q) signal  203 , respectively. The phase-shifted LO signal may cause the output signal from second processing path P 2  to be a phase-shifted version of the output signal from first processing path P 1 . 
     When configurable amplifier  200  operates in the cancelling mode, second processing path P 2  may mix together the baseband signal and the shifted LO signal. For example, LO_shifted (I) signal  205  may be selected by first LO signal selector  245  and provided to third mixer  220 . Third mixer  220  may mix together LO_shifted (I) signal  205  and baseband (I) signal  202  and provide the third mixer output signal to second summing node  227 . LO_shifted (Q) signal  206  may be selected by second LO signal selector  246  and provided to fourth mixer  225 . Fourth mixer  225  may mix together LO_shifted (Q) signal  206  and baseband (Q) signal  204  and provide the fourth mixer output signal to second summing node  227 . Output signals from third mixer  220  and fourth mixer  225  may be summed together at second summing node  227  and the resulting summed signal provided to second buffer  235 . 
     The first up-converted communication signal  274  output from first transistor pair  260  and the second up-converted communication signal  276  output from second transistor pair  261  may be summed together at third summing node  241 . Referring back to eq. 5, a ninety degree phase-shifted LO signal may be expressed by eq. 9, shown below:
 
LO_shifted signal=sin α+cos α  (eq. 9)
 
where: cos α is associated with LO_shifted (I) signal  205 ; and
 
     sin α is associated with LO_shifted (Q) signal  206 . 
     Baseband signal may still be expressed by eq. 6. When configurable amplifier  200  operates in the cancelling mode, second processing path P 2  may generate an output signal described by eq. 10 shown below:
 
output signal  P 2=sin α cos β−cos α sin β  (eq. 10)
     where: sin α cos β is associated with mixing LO_shifted (Q) signal  206  together with baseband (Q) signal  204 ; and
       cos α sin β is associated with mixing LO_shifted (I) signal  205  together with baseband (I) signal  202 .   
       

     The output signal for first processing path P 1  (eq. 7) may be rewritten as:
 
cos(α+β)=cos α cos β−sin α sin β  (eq. 11)
 
     In a similar manner, the output signal for second processing path P 2  (eq. 10) may be rewritten as:
 
sin(α+β)=sin α cos β+cos α sin β)  (eq. 12)
 
     Thus, configurable amplifier output signal  275  may be expressed by eq. 13 below:
 
configurable amplifier output signal 275=sin(α+β)+cos(α+β)  (eq. 13)
 
     In other words, when configurable amplifier  200  operates in the cancelling mode, configurable amplifier output signal  275  is based, at least in part, on a first signal (e.g., sin(α+β)) and a ninety degree phase-shifted version of the first signal (e.g., cos(α+β)). Thus, configurable amplifier output signal  275  may have a reduced or cancelled second harmonic component. 
       FIG. 3  is a block diagram of a mode controller  300 , in accordance with example embodiments. Mode controller  300  may include a control block  310  and a signal generator  320 . Control block  310  may drive a mode control signal  315  to a state that may cause configurable amplifier  200  to operate in the normal operating mode or the cancelling mode, as described above. In some embodiments, control block  310  may drive mode control signal  315  to a first state that may cause configurable amplifier  200  to operate in the normal operating mode when little or no cancelling of the second harmonic component of configurable amplifier output signal  275  is desired. Control block  310  may drive mode control signal  315  to a second state that may cause configurable amplifier  200  to operate in the cancelling mode when a cancelling or reduction of the second harmonic component of configurable amplifier output signal  275  is desired. For example, based on a characteristic frequency of an input signal for configurable amplifier  200 , a second harmonic component of configurable amplifier output signal  275  may interfere with one or more devices and/or circuits within wireless device  102 . Thus, configurable amplifier  200  may be operated in cancelling mode to reduce or cancel the second harmonic component and reduce any associated interference. 
     Signal generator  320  may receive mode control signal  315  and, in response thereto, may generate LO select signal  240 . For example, in some embodiments, when configurable amplifier  200  operates in the normal mode, LO select signal  240  may not be asserted and/or be at a low logic level (or a first logical state) to enable first LO signal selector  245  and second LO signal selector  246  to select LO (I) signal  201  and LO (Q) signal  203 , respectively. When configurable amplifier  200  operates in the cancelling mode, LO select signal  240  may be asserted and/or be at a high logic level (or a second logical state) to enable first LO signal selector  245  and second LO signal selector  246  to select LO_shifted (I) signal  205  and LO_shifted (Q) signal  206 , respectively. 
       FIG. 4  shows a wireless device  400  that is one embodiment of wireless device  102  and/or  103  of  FIG. 1 . Wireless device  400  includes a transceiver  410 , a processor  430 , a memory  440 , and one or more antennas  450 . Transceiver  410  may transmit and receive communication signals. Transceiver  410  may include configurable amplifier  420  to amplify communication signals associated with transceiver  410 . For some embodiments, configurable amplifier  420  may another embodiment of configurable amplifier  135  of  FIG. 1  and/or configurable amplifier  200  of  FIG. 2 . 
     Memory  440  may include a non-transitory computer-readable storage medium (e.g., one or more nonvolatile memory elements, such as EPROM, EEPROM, Flash memory, a hard drive, etc.) that may store the following software modules:
         transceiver control module  442  to control transceiver  410  to transmit and receive communication signals in accordance with one or more communication protocols; and   configurable amplifier control module  444  to control configurable amplifier  420  to amplify one or more communication signals within transceiver  410 .       

     Each software module includes program instructions that, when executed by processor  430 , may cause the wireless device  400  to perform the corresponding function(s). Thus, the non-transitory computer-readable storage medium of memory  440  may include instructions for performing all or a portion of the operations of  FIG. 5 . 
     Processor  430 , which is coupled transceiver  410  and memory  440 , may be any one or more suitable processors capable of executing scripts or instructions of one or more software programs stored in the wireless device  400  (e.g., within memory  440 ). 
     Processor  430  may execute transceiver control module  442  to configure transceiver  410  to receive and/or transmit communication signals in accordance with a communication protocol. In some embodiments, transceiver control module  442  may determine an operating frequency (e.g., carrier frequency) for transceiver  410 . 
     Processor  430  may execute configurable amplifier control module  444  to select an operating mode for configurable amplifier  420 . For example, based on a selected operating frequency used by transceiver  410 , configurable amplifier control module  444  may determine an operating mode for configurable amplifier  420 . In some embodiments, when a second harmonic frequency of a signal amplified by configurable amplifier  420  may interfere with another component and/or circuit within wireless device  400 , then configurable amplifier control module  444  may operate configurable amplifier  420  in the cancelling mode. Conversely, when the second harmonic frequency of the signal amplified by configurable amplifier  420  may not interfere with another component and/or circuit within wireless device  400 , then configurable amplifier control module  444  may operate configurable amplifier  420  in the normal mode. 
       FIG. 5  shows an illustrative flow chart depicting an exemplary operation  500  for operating configurable amplifier  420 , in accordance with example embodiments. Referring also to  FIGS. 2-4 , a first up-converted communication signal is generated ( 502 ). The first up-converted communication signal may be generated by first processing path P 1 , and may be based, at least in part, on a first local oscillator signal and a baseband signal. In some embodiments, the first local oscillator signal and the baseband signal may be quadrature signals. 
     An operating mode of the configurable amplifier  420  is selected ( 504 ). For example, when it is desired to cancel second-order harmonics of the output signal, then the first mode may be selected. Conversely, when it is not desired (or necessary) to cancel the second-order harmonics of the output signal (e.g., but rather to increase the magnitude of the output signal relative to the first mode), then the second mode may be selected. 
     Next, a second up-converted communication signal is generated ( 506 ). More specifically, for at least some example embodiments, when the configurable amplifier  420  is selected to operate in the first mode, the second up-converted communication signal is generated to be a substantially ninety degree phase-shifted version of the first up-converted communication signal ( 506 A). Conversely, when the configurable amplifier  420  is selected to operate in the second mode, the second up-converted communication signal is generated to be substantially the same as the first up-converted communication signal ( 506 B). Then, an output signal is generated based, at least in part, on the first up-converted communication signal and the second up-converted communication signal ( 508 ). 
     The first up-converted communication signal  274  may be based, at least in part, on a first local oscillator signal and a baseband signal, and the second up-converted communication signal  276  may be based, at least in part, on a second local oscillator signal and the baseband signal. In some embodiments, the second local oscillator signal may be a substantially ninety degree phase-shifted version of the first local oscillator signal when the configurable amplifier  420  is selected to operate in the first mode, and the second local oscillator signal may be substantially similar to the first local oscillator signal when the configurable amplifier  420  is selected to operate in the second mode. In some embodiments, the second local oscillator signal and the baseband signal may be quadrature signals. 
     In the foregoing specification, the present embodiments have been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader scope of the disclosure as set forth in the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.