PATENT DOCUMENT

Publication Number: US-11632224-B2
Application Number: US-202217832171-A
Country: US
Kind Code: B2

Title: Leakage and noise cancelling for double balanced duplexers

Abstract:
Systems and method are described for improving electrical isolation between a transmission signal and receiver circuitry of a transceiver communicating over one or more wireless networks via one or more shared antennas. The transceiver may include isolation circuitry to facilitate isolation of the transmission signal from the receiver circuitry. However, a leakage current of the transmission signal and noise signals may appear at the receiver circuitry. Presence of the leakage current or the noise signals in the receiver circuitry may cause interference with the reception signal. As such, the isolation circuitry may benefit from additional isolation between the transmission signal and the receiver circuitry to reduce an effect of the leakage current and the noise signals on the reception signal.

Claims:
The invention claimed is: 
     
       1. Radio frequency transceiver circuitry comprising:
 isolation circuitry electrically coupled to one or more antennas; 
 transmit circuitry electrically coupled to the isolation circuitry and configured to send a transmission signal via the one or more antennas; 
 receiver circuitry electrically coupled to the isolation circuitry and configured to receive a receive signal via the one or more antennas; 
 first phase adjustment circuitry electrically coupled between the transmit circuitry and the receiver circuitry, the first phase adjustment circuitry configured to adjust a phase of a first feedback signal from the transmit circuitry and provide the first feedback signal, as adjusted, to the receiver circuitry to compensate for at least a portion of a noise signal at the receiver circuitry generated by the transmit circuitry when sending the transmission signal via the one or more antennas; and 
 second phase adjustment circuitry electrically coupled between the transmit circuitry and the receiver circuitry, the second phase adjustment circuitry configured to adjust a phase of a second feedback signal from the transmit circuitry and provide the second feedback signal, as adjusted, to the receiver circuitry to compensate for at least a portion of a leakage signal at the receiver circuitry generated by the transmit circuitry when sending the transmission signal via the one or more antennas. 
 
     
     
       2. The radio frequency transceiver circuitry of  claim 1 , wherein the isolation circuitry comprises a first balun and a second balun, the first balun configured to electrically couple the transmit circuitry and the one or more antennas, and the second balun configured to electrically couple the receiver circuitry and the one or more antennas. 
     
     
       3. The radio frequency transceiver circuitry of  claim 1 , wherein the first phase adjustment circuitry comprises a balun configured to filter at least a portion of the first feedback signal outside of a frequency range of the receiver circuitry. 
     
     
       4. The radio frequency transceiver circuitry of  claim 1 , wherein the transmit circuitry comprises a power amplifier having an output electrically coupled to the first phase adjustment circuitry, the power amplifier configured to generate the noise signal. 
     
     
       5. The radio frequency transceiver circuitry of  claim 1 , wherein the second phase adjustment circuitry comprises a balun configured to filter at least a portion of the second feedback signal outside of a frequency range of the transmit circuitry. 
     
     
       6. The radio frequency transceiver circuitry of  claim 1 , comprising gain adjustment circuitry configured to adjust an amplitude of the second feedback signal to compensate for at least the portion of the leakage signal. 
     
     
       7. The radio frequency transceiver circuitry of  claim 6 , comprising amplitude sensing circuitry configured to determine an amplitude of the leakage signal, wherein the gain adjustment circuitry is configured to adjust the amplitude of the second feedback signal based on receiving the amplitude of the leakage signal from the amplitude sensing circuitry. 
     
     
       8. The radio frequency transceiver circuitry of  claim 1 , comprising phase sensing circuitry configured to determine a phase of the transmission signal, the first phase adjustment circuitry being configured to adjust the phase of the first feedback signal based on the phase of the transmission signal to compensate for the noise signal, the second phase adjustment circuitry being configured to adjust the phase of the second feedback signal based on the phase of the transmission signal to compensate for the leakage signal, or both. 
     
     
       9. An electronic device comprising:
 transmission circuitry configured to send a transmission signal to one or more antennas; 
 receiver circuitry configured to receive a reception signal from the one or more antennas; 
 a feedback path coupled to the transmission circuitry and the receiver circuitry configured to provide a feedback signal from the transmission circuitry to the receiver circuitry to compensate for a leakage signal or a noise signal at the receiver circuitry generated by the transmission signal when sending the transmission signal to the one or more antennas; and 
 phase adjustment circuitry disposed on the feedback path and configured to adjust a phase of the feedback signal to compensate for the leakage signal or the noise signal. 
 
     
     
       10. The electronic device of  claim 9 , comprising isolation circuitry having
 a shared conductive path between the one or more antennas, the transmission circuitry, and the receiver circuitry, 
 a first balun configured to provide electrical isolation between the transmission signal on the shared conductive path and the receiver circuitry, and 
 a second balun configured to provide electrical isolation between the reception signal on the shared conductive path and the transmission circuitry. 
 
     
     
       11. The electronic device of  claim 9 , comprising a balun disposed on the feedback path, the balun configured to filter at least a portion of the feedback signal outside of a frequency range of the receiver circuitry. 
     
     
       12. The electronic device of  claim 9 , wherein the transmission circuitry comprises a power amplifier having an output electrically coupled to the feedback path. 
     
     
       13. The electronic device of  claim 9 , comprising a balun disposed on the feedback path, the balun configured to filter at least a portion of the feedback signal outside of a frequency range of the transmission circuitry. 
     
     
       14. The electronic device of  claim 9 , comprising gain adjustment circuitry disposed on the feedback path, wherein the gain adjustment circuitry is configured to adjust an amplitude of the feedback signal to compensate for the leakage signal. 
     
     
       15. The electronic device of  claim 9 , comprising phase sensing circuitry configured to determine a phase of the transmission signal, wherein the phase adjustment circuitry is configured to adjust the phase of the feedback signal based on the phase of the transmission signal to compensate for the noise signal, the leakage signal, or both. 
     
     
       16. An electronic device, comprising:
 one or more antennas; 
 receiver circuitry coupled to the one or more antennas; 
 transmission circuitry coupled to the one or more antennas; 
 first phase adjustment circuitry coupled to the receiver circuitry and the transmission circuitry; and 
 isolation circuitry coupled to the receiver circuitry, the transmission circuitry, and the one or more antennas, the isolation circuitry comprising a first balun coupled to the transmission circuitry and the one or more antennas and a second balun coupled to the receiver circuitry and the one or more antennas. 
 
     
     
       17. The electronic device of  claim 16 , wherein the first phase adjustment circuitry is configured to adjust a phase of a first feedback signal from the transmission circuitry to the receiver circuitry. 
     
     
       18. The electronic device of  claim 16 , comprising second phase adjustment circuitry coupled to the receiver circuitry and the transmission circuitry, the second phase adjustment circuitry configured to provide a second feedback signal from the transmission circuitry to the receiver circuitry. 
     
     
       19. The electronic device of  claim 16 , wherein the first phase adjustment circuitry comprises gain adjustment circuitry configured to adjust an amplitude of a first feedback signal from the transmission circuitry to the receiver circuitry. 
     
     
       20. The electronic device of  claim 16 , wherein the first phase adjustment circuitry comprises a band pass filter configured to filter at least a portion of one or more signals outside a first frequency range.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 17/065,397 entitled “LEAKAGE AND NOISE CANCELLING FOR DOUBLE BALANCED DUPLEXERS,” filed on Oct. 7, 2020, which is hereby incorporated by reference in its entirety for all purposes. 
    
    
     BACKGROUND 
     The present disclosure relates generally to wireless communication systems and, more specifically, to isolating receivers from transmission signals in wireless communication devices. 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     Electronic devices are being used more and more every day to transfer data between users, to control smart home devices, stream movies and shows, and so on. As the amount of data being communicated using electronic devices is increasing, maintaining integrity of the communicated data becomes more and more important. For example, in an electronic device, a transmitter and a receiver may be coupled to one or more antennas to enable the electronic device to transmit and receive wireless signals. To increase an amount of data able to be sent and received and decrease a time between sending and receiving the data, the electronic device may enable full duplex operations (e.g., sending data while receiving data) via frequency division duplexing (FDD). That is, transmission signals may be sent via the one or more antennas over a first frequency range while received signals may be received via the one or more antennas over a second frequency range different than the first. To enable these FDD-full duplex operations, the electronic device may include isolation circuitry that isolate transmission signals from the receiver and isolate the received signals from the transmitter. 
     The transmitter includes a power amplifier that amplifies a transmission signal so that the transmission signal may be provided to the one or more antennas with sufficient transmission power. However, the amplifier may introduce noise to the transmission signals (e.g., in the receive frequency band) that may result in interference and reduced data reliability at the receiver of the electronic device. 
     Moreover, certain electronic devices may use electrical components (e.g., baluns) that may isolate the transmitter from received signals, and the receiver from transmission signals. However, the electrical components may provide less than ideal isolation between the transmission signal and the receiver due to non-ideal characteristics of real-world electrical components. This less than ideal isolation may lead to leakage of the transmission signal to the receiver, which may cause interference at the receiver. 
     SUMMARY 
     A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below. 
     In some embodiments, the isolation circuitry may extend one or more auxiliary signal paths between the transmission circuitry and the receiver circuitry to reduce an effect of the leakage current and/or the noise signals in reception signal. Such auxiliary signal paths may provide one or more feedback signals from the transmission circuitry to the receiver circuitry to cancel the leakage current and/or the noise signals. The one or more feedback signal may include an adjusted portion of the transmission signal. The auxiliary signal paths may each include phase adjustment circuitry. For example, a first auxiliary signal path may provide the first feedback signal 180 degrees out of phase compared to the transmission signal to cancel the leakage current. In some embodiments, the auxiliary signal paths may also include gain adjustment circuitry. The gain adjustment circuitry may adjust a current or an amplitude of the first feedback signal to reduce or cancel the leakage current. 
     In different embodiments, the first auxiliary signal path may be connected to the transmitter circuitry before the PA (e.g., an input node of the PA) or after the PA (e.g., an output node of the PA). In the first embodiment, the first auxiliary signal path is connected to the transmitter circuitry before the PA. The first feedback signal may provide an adjusted portion of the transmission signal for cancelling the leakage current at the receiver circuitry. The first auxiliary signal path may include phase adjustment circuitry and/or gain adjustment circuitry to provide the adjusted portion of the transmission signal for cancelling the leakage current. 
     In a second embodiment, the first auxiliary signal path is connected to the transmitter circuitry after the PA. The first feedback signal may provide the adjusted portion of the transmission signal with the noise signals (e.g., generated by the PA) for cancelling the leakage current at the receiver circuitry. The first auxiliary signal path may include phase adjustment circuitry and/or gain adjustment circuitry to provide the adjusted portion of the transmission signal for cancelling the leakage current. Moreover, in the second embodiment, the first auxiliary signal path may include a bandpass filter to prevent the noise signals from distorting the first feedback signal. That is, the bandpass filter may allow a portion of the first feedback signal that is within the transmission frequency band to cancel the leakage current and prevent a portion of the first feedback signal that is outside the transmission frequency band from the receiver circuitry. 
     In a third embodiment, the isolation circuitry may extend a second auxiliary signal path between the transmission circuitry and the receiver circuitry to reduce or cancel the noise signals. The second auxiliary signal path may provide a second feedback signal from the transmission circuitry to the receiver circuitry to cancel the noise signals of the transmission signal within the reception frequency band. The second feedback signal may include a different adjusted portion of the transmission signal to cancel the noise signals at the receiver circuitry. The second auxiliary signal path may include phase adjustment circuitry and/or gain adjustment circuitry to provide the adjusted portion of the transmission signal for cancelling the noise signals at the receiver circuitry. 
     In one embodiment, a radio frequency transceiver circuitry may include a first balun and a second balun. The first balun and the second balun may be electrically coupled to one or more antennas. The radio frequency transceiver circuitry may also include transmit circuitry electrically coupled to the first balun. The transmit circuitry may send a transmission signal via the one or more antennas. The radio frequency transceiver circuitry may include receiver circuitry. The receiver circuitry may electrically couple to the second balun. Moreover, the receiver circuitry may receive a receive signal using the one or more antennas. The radio frequency transceiver circuitry may also include phase adjustment circuitry. The phase adjustment circuitry may electrically couple between the transmit circuitry and the second balun. The phase adjustment circuitry may adjust a phase of a feedback signal. Moreover, the phase adjustment circuitry may provide the feedback signal from the transmit circuitry to the second balun to compensate for a leakage or noise signal generated by the transmit circuitry when sending the transmission signal via the one or more antennas. 
     In another embodiment, an electronic device may include one or more antennas. The electronic device may also include transmission circuitry to send a transmission signal to the one or more antennas. The receiver circuitry configured to receive a reception signal from the one or more antennas. The electronic device may also include isolation circuitry to provide electrical isolation between the transmission signal and the receiver circuitry. Moreover, the isolation circuitry may provide electrical isolation between the reception signal and the transmission circuitry. The electronic device may also include a feedback path between the transmission circuitry and the receiver circuitry. The feedback path may provide a feedback signal from the transmission circuitry to the receiver circuitry. The electronic device may also include a phase adjustment circuitry disposed on the feedback path. The phase adjustment circuitry may adjust a phase of the feedback signal to compensate for a leakage or noise signal generated by the transmission circuitry when sending the transmission signal to the one or more antennas. 
     In yet another embodiment, an electronic device may include antenna means, means for transmitting a transmission signal via the antenna means, means for receiving a receive signal via the antenna means, and means for isolating the receiving means from the transmission signal. The isolating means may include means for providing a feedback signal from the transmitting means to the receiving means. Moreover, the isolating means may include means for adjusting a phase of the feedback signal to compensate for a leakage or noise signal generated by the transmitting means when transmitting a transmission signal via the antenna means. 
     Various refinements of the features noted above may exist in relation to various aspects of the present disclosure. Further features may also be incorporated in these various aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above-described aspects of the present disclosure alone or in any combination. The brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of embodiments of the present disclosure without limitation to the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings described below. 
         FIG.  1    is a block diagram of an electronic device, according to an embodiment of the present disclosure. 
         FIG.  2    is a perspective view of a notebook computer representing an embodiment of the electronic device of  FIG.  1   . 
         FIG.  3    is a front view of a handheld device representing another embodiment of the electronic device of  FIG.  1   . 
         FIG.  4    is a front view of another handheld device representing another embodiment of the electronic device of  FIG.  1   . 
         FIG.  5    is a front view of a desktop computer representing another embodiment of the electronic device of  FIG.  1   . 
         FIG.  6    is a perspective view of a wearable electronic device representing another embodiment of the electronic device of  FIG.  1   . 
         FIG.  7    is a block diagram of example transceiver circuitry of the electronic device of  FIG.  1   , according to an embodiment of the present disclosure. 
         FIG.  8 A  is a block diagram of receiver circuitry of the example transceiver circuitry of  FIG.  7   , according to an embodiment of the present disclosure. 
         FIG.  8 B  is a block diagram of transmitter circuitry of the example transceiver circuitry of  FIG.  7   , according to an embodiment of the present disclosure. 
         FIG.  9    is a schematic diagram of the example transceiver circuitry of  FIG.  7   , according to an embodiment of the present disclosure. 
         FIG.  10    is a schematic diagram of an embodiment of the transceiver circuitry of  FIG.  9    having a feedback path that reduces or compensates for a leakage signal from the transmitter circuitry to the receiver circuitry. 
         FIG.  11    is a schematic diagram of an embodiment of the transceiver circuitry of  FIG.  9    having a feedback path that reduces or compensates for a leakage signal from the transmitter circuitry to the receiver circuitry, where the leakage signal includes noise signals. 
         FIG.  12    is a schematic diagram of an embodiment of the transceiver circuitry of  FIG.  9    having a feedback path that reduces or compensates for noise signals generated by the transmitter circuitry at the receiver circuitry. 
         FIG.  13    is a schematic diagram of an example embodiment of the transceiver circuitry of the electronic device of  FIG.  1    that reduces or compensates for leakage and noise signals associated with a transmission signal at the receiver circuitry using two feedback paths according to the embodiments of  FIG.  10    and  FIG.  12   . 
         FIG.  14    is a schematic diagram of another example embodiment of the transceiver circuitry of the electronic device of  FIG.  1    that reduces or compensates for leakage and noise signals associated with a transmission signal at the receiver circuitry using two feedback paths according to the embodiments of  FIG.  11    and  FIG.  12   . 
     
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Use of the term “approximately,” “near,” “about”, and/or “substantially” should be understood to mean including close to a target (e.g., design, value, amount), such as within a margin of any suitable or contemplatable error (e.g., within 0.1% of a target, within 1% of a target, within 5% of a target, within 10% of a target, within 25% of a target, and so on). 
     With the foregoing in mind, there are many suitable communication devices that may include and use transceiver circuitry that reduces or compensates for leakage or noise signals from transmitter circuitry to receiver circuitry, as described herein. Turning first to  FIG.  1   , an electronic device  10  according to an embodiment of the present disclosure may include, among other things, a processor core complex  12  including one or more processor(s), memory  14 , nonvolatile storage  16 , a display  18 , input structures  22 , an input/output (I/O) interface  24 , a network interface  25 , and a power source  30 . The various functional blocks shown in  FIG.  1    may include hardware elements (including circuitry), software elements (including computer code stored on a computer-readable medium) or a combination of both hardware and software elements. It should be noted that  FIG.  1    is merely one example of a particular implementation and is intended to illustrate the types of components that may be present in electronic device  10 . 
     By way of example, the electronic device  10  may represent a block diagram of the notebook computer depicted in  FIG.  2   , the handheld device depicted in  FIG.  3   , the handheld device depicted in  FIG.  4   , the desktop computer depicted in  FIG.  5   , the wearable electronic device depicted in  FIG.  6   , or similar devices. It should be noted that the processor(s)  12  and other related items in  FIG.  1    may be generally referred to herein as “data processing circuitry.” Such data processing circuitry may be embodied wholly or in part as software, software, hardware, or any combination thereof. Furthermore, the processor(s)  12  and other related items in  FIG.  1    may be a single contained processing module or may be incorporated wholly or partially within any of the other elements within the electronic device  10 . 
     In the electronic device  10  of  FIG.  1   , the processor(s)  12  may be operably coupled with a memory  14  and a nonvolatile storage  16  to perform various algorithms. Such programs or instructions executed by the processor(s)  12  may be stored in any suitable article of manufacture that includes one or more tangible, computer-readable media. The tangible, computer-readable media may include the memory  14  and/or the nonvolatile storage  16 , individually or collectively, to store the instructions or routines. The memory  14  and the nonvolatile storage  16  may include any suitable articles of manufacture for storing data and executable instructions, such as random-access memory, read-only memory, rewritable flash memory, hard drives, and optical discs. In addition, programs (e.g., an operating system) encoded on such a computer program product may also include instructions that may be executed by the processor(s)  12  to enable the electronic device  10  to provide various functionalities. 
     In certain embodiments, the display  18  may be a liquid crystal display (LCD), which may facilitate users to view images generated on the electronic device  10 . In some embodiments, the display  18  may include a touch screen, which may facilitate user interaction with a user interface of the electronic device  10 . Furthermore, it should be appreciated that, in some embodiments, the display  18  may include one or more light-emitting diode (LED) displays, organic light-emitting diode (OLED) displays, active-matrix organic light-emitting diode (AMOLED) displays, or some combination of these and/or other display technologies. 
     The input structures  22  of the electronic device  10  may enable a user to interact with the electronic device  10  (e.g., pressing a button to increase or decrease a volume level). The I/O interface  24  may enable electronic device  10  to interface with various other electronic devices, as may the network interface  25 . The network interface  25  may include, for example, one or more interfaces for a personal area network (PAN), such as a BLUETOOTH® network, for a local area network (LAN) or wireless local area network (WLAN), such as an 802.11x WI-FI® network, and/or for a wide area network (WAN), such as a 3 rd  generation (3G) cellular network, universal mobile telecommunication system (UMTS), 4 th  generation (4G) cellular network, long term evolution (LTE®) cellular network, long term evolution license assisted access (LTE-LAA) cellular network, 5 th  generation (5G) cellular network, and/or New Radio (NR) cellular network. In particular, the network interface  25  may include, for example, one or more interfaces for using a Release-15 cellular communication standard of the 5G specifications that include the millimeter wave (mmWave) frequency range (e.g., 24.25-300 gigahertz (GHz)). The network interface  25  of the electronic device  10  may allow communication over the aforementioned networks (e.g., 5G, Wi-Fi, LTE-LAA, and so forth). 
     The network interface  25  may also include one or more interfaces, for example, for broadband fixed wireless access networks (e.g., WIMAX®), mobile broadband Wireless networks (mobile WIMAX®), asynchronous digital subscriber lines (e.g., ADSL, VDSL), digital video broadcasting-terrestrial (DVB-T®) network and its extension DVB Handheld (DVB-H®) network, ultra-wideband (UWB) network, alternating current (AC) power lines, and so forth. In some embodiments, network interfaces  25  may be capable of joining multiple networks, and may employ one or more antennas  20  to that end. 
     In some examples, the network interface  25  may include a transceiver circuitry  29 , among other things. The transceiver circuitry  29  may facilitate communication via the one or more antennas  20  to enable the electronic device  10  to transmit and receive wireless signals. The transceiver circuitry  29  may include isolation circuitry  26 , a receiver  27 , and a transmitter  28 . The isolation circuitry  26  may enable bidirectional communication over a shared signal path while separating signals traveling in each direction from one another. In particular, the isolation circuitry  26  may isolate the transmitter  28  from a received signal and/or isolate the receiver  27  from a transmission signal (e.g., isolate the transmitter from the receiver, and vice versa) to enable bidirectional communication. 
     In some embodiments, the isolation circuitry  26  may include one or more duplexers (e.g., a double balance duplexer (DBD)) that isolates the transmitter  28  from a received signal and/or isolates the receiver  27  from a transmission signal. In different embodiments, the isolation circuitry  26  may use different electrical components (e.g., balance-unbalance transformers or baluns) for providing the described isolation. However, one or more components of the isolation circuitry  26  may include non-ideal electrical characteristics. Such non-ideal characteristics of components associated with the network interface  25  may disturb the duplex function and degrade isolation between the transmitter  28  and the receiver  27 . To prevent such disruption, additional circuitry may be used to reduce the effect of components with non-ideal characteristics in the receiver  27 . 
     In some embodiments, the network interface  25  may transmit and receive RF signals to support voice and/or data communication in wireless applications such as, for example, PAN networks (e.g., BLUETOOTH®), WLAN networks (e.g., 802.11x WI-FI®), WAN networks (e.g., 3G, 4G, 5G, NR, and LTE® and LTE-LAA cellular networks), WIMAX® networks, mobile WIMAX® networks, ADSL and VDSL networks, DVB-T® and DVB-H® networks, UWB networks, and so forth. As further illustrated, the electronic device  10  may include the power source  30 . The power source  30  of the electronic device  10  may include any suitable source of power, such as a rechargeable lithium polymer (Li-poly) battery and/or an alternating current (AC) power converter. 
     In certain embodiments, the electronic device  10  may take the form of a computer, a portable electronic device, a wearable electronic device, or other type of electronic device. Such computers may be generally portable (such as laptop, notebook, and tablet computers), or generally used in one place (such as conventional desktop computers, workstations, and/or servers). In certain embodiments, the electronic device  10  in the form of a computer may be a model of a MacBook®, MacBook® Pro, MacBook Air®, iMac®, Mac® mini, or Mac Pro® available from Apple Inc. of Cupertino, Calif. 
     By way of example, the electronic device  10 , taking the form of a notebook computer  10 A, is illustrated in  FIG.  2    in accordance with one embodiment of the present disclosure. The depicted notebook computer  10 A may include a housing or enclosure  36 , a display  18 , input structures  22 , and ports of an I/O interface  24 . In one embodiment, the input structures  22  (such as a keyboard and/or touchpad) may be used to interact with the computer  10 A, such as to start, control, or operate a graphical user interface (GUI) and/or applications running on computer  10 A. For example, a keyboard and/or touchpad may allow a user to navigate a user interface and/or application interface displayed on display  18 . 
       FIG.  3    depicts a front view of a handheld device  10 B, which represents one embodiment of the electronic device  10 . The handheld device  10 B may represent, for example, a portable phone, a media player, a personal data organizer, a handheld game platform, or any combination of such devices. By way of example, the handheld device  10 B may be a model of an iPod® or iPhone® available from Apple Inc. of Cupertino, Calif. The handheld device  10 B may include an enclosure  36  to protect interior components from physical damage and/or to shield them from electromagnetic interference. The enclosure  36  may surround the display  18 . The I/O interfaces  24  may open through the enclosure  36  and may include, for example, an I/O port for a hardwired connection for charging and/or content manipulation using a standard connector and protocol, such as the Lightning connector provided by Apple Inc. of Cupertino, Calif., a universal serial bus (USB), or other similar connector and protocol. 
     The input structures  22 , in combination with the display  18 , may allow a user to control the handheld device  10 B. For example, the input structures  22  may activate or deactivate the handheld device  10 B, navigate the user interface to a home screen, a user-configurable application screen, and/or activate a voice-recognition feature of the handheld device  10 B . Other input structures  22  may provide volume control, or may toggle between vibrate and ring modes. The input structures  22  may also include a microphone that may obtain a user&#39;s voice for various voice-related features, and a speaker that may enable audio playback and/or certain phone capabilities. The input structures  22  may also include a headphone input that may provide a connection to external speakers and/or headphones. 
       FIG.  4    depicts a front view of another handheld device  10 C, which represents another embodiment of the electronic device  10 . The handheld device  10 C may represent, for example, a tablet computer, or one of various portable computing devices. By way of example, the handheld device  10 C may be a tablet-sized embodiment of the electronic device  10 , which may be, for example, a model of an iPad® available from Apple Inc. of Cupertino, Calif. 
     Turning to  FIG.  5   , a computer  10 D may represent another embodiment of the electronic device  10  of  FIG.  1   . The computer  10 D may be any computer, such as a desktop computer, a server, or a notebook computer, but may also be a standalone media player or video gaming machine. By way of example, the computer  10 D may be an iMac®, a MacBook®, or another similar device by Apple Inc. of Cupertino, Calif. It should be noted that the computer  10 D may also represent a personal computer (PC) by another manufacturer. A similar enclosure  36  may be provided to protect and enclose internal components of the computer  10 D, such as the display  18 . In certain embodiments, a user of the computer  10 D may interact with the computer  10 D using various peripheral input structures  22 , such as the keyboard  22 A or mouse  22 B (e.g., input structures  22 ), which may connect to the computer  10 D. 
     Similarly,  FIG.  6    depicts a wearable electronic device  10 E representing another embodiment of the electronic device  10  of  FIG.  1    that may operate using the techniques described herein. By way of example, the wearable electronic device  10 E, which may include a wristband  43 , may be an Apple Watch® by Apple Inc. of Cupertino, Calif. However, in other embodiments, the wearable electronic device  10 E may include any wearable electronic device such as, for example, a wearable exercise monitoring device (e.g., pedometer, accelerometer, heart rate monitor), or other device by another manufacturer. The display  18  of the wearable electronic device  10 E may include a touch screen display  18  (e.g., LCD, LED display, OLED display, active-matrix organic light emitting diode (AMOLED) display, and so forth), as well as input structures  22 , which may allow users to interact with a user interface of the wearable electronic device  10 E. 
     With the foregoing in mind,  FIG.  7    is a block diagram of example transceiver circuitry  29 , according to an embodiment of the present disclosure. The transceiver circuitry  29  may include the isolation circuitry  26  communicatively coupled to and/or disposed between transmit (TX) circuitry  52  and receiver (RX) circuitry  54 . In some embodiments, the isolation circuitry  26  may enable FDD. That is, the isolation circuitry  26  may allow a transmission signal (TX signal) of a first frequency band to pass through from the TX circuitry  52  (e.g., via a transformer effect) to the one or more antennas  20  while blocking signals within the first frequency band from passing through to the RX circuitry  54 . Moreover, the isolation circuitry  26  may allow a reception signal (RX signal) of a second frequency band to pass through from the antennas  20  to the RX circuitry  54  (e.g., via circuit paths) while blocking signals within the second frequency band from passing through to the TX circuitry  52 . 
     Each frequency band may be of any suitable bandwidth, such as between 1 megahertz (MHz) and 100 gigahertz (GHz) (e.g., 10 MHz), and include any suitable frequencies. For example, the first frequency band (e.g., the TX frequency band) may be between 880 and 890 MHz, and the second frequency band (e.g., the RX frequency band) may be between 925 and 936 MHz. 
     A shared path  60  may couple the isolation circuitry  26  to the one or more antennas  20 . The shared path  60  may be bidirectional and may enable communication of the TX signal from the TX circuitry  52  to the one or more antennas  20 , and/or the RX signal from the one or more antennas  20  to the RX circuitry  54 . 
       FIG.  8 A  is a schematic diagram of the TX circuitry  52 , according to an embodiment of the present disclosure. As illustrated, the TX circuitry  52  may include, for example, a power amplifier (PA)  70 , a modulator  72 , and a digital-to-analog converter (DAC)  74 . In some embodiments, the TX circuitry  52  may include additional or alternative components. Nevertheless, a digital signal containing information to be transmitted via the one or more antennas  20  may be provided to the DAC  74 . The DAC  74  may convert the received digital signal to an analog signal. The modulator  72  may combine the converted analog signal with a carrier signal to generate a radio wave. 
     The PA  70  may receive the modulated signal from the modulator  72 . The PA  70  may then amplify the modulated signal to a suitable level to drive transmission of the signal via the one or more antennas  20  (e.g., the TX signal). In some embodiments, the PA  70  may output the amplified TX signal with noise signals distorted over a wider or different range of frequency compared to the TX frequency band (e.g., within the RX frequency band). In some embodiments, the PA-generated noise signals may traverse the isolation circuitry  26  to the RX circuitry  54  and may degrade a signal integrity of the RX signal. For example, the PA-generated noise signals may distort the RX signal within the RX circuitry  54 . In additional or alternative embodiments, the TX signal may include noise signals (e.g., within the RX frequency band) generated by other electrical components associated with different circuitry that may traverse the isolation circuitry  26  to the RX circuitry  54  and may degrade the signal integrity of the RX signal. 
       FIG.  8 B  is a schematic diagram of the RX circuitry  54 , according to an embodiment of the present disclosure. As illustrated, the RX circuitry  54  may include, for example, a low noise amplifier (LNA)  80 , a demodulator  82 , and an analog-to-digital converter (ADC)  84 . One or more signals received by the one or more antennas  20  may be sent to the RX circuitry  54  via the isolation circuitry  26 . In some embodiments, the RX circuitry  54  may include additional or alternative components. 
     The LNA  80  may receive the RX signal received by the one or more antennas  20  via the isolation circuitry  26 . Subsequently, the RX signal is sent to the demodulator  82 . The demodulator  82  may remove the RF envelope and extract a demodulated signal from the RX signal for processing. The ADC  84  receives the demodulated analog signal and converts the signal to a digital signal so that it can be further processed by the electronic device  10 . 
     In some cases, the LNA  80  may also receive other signals (e.g., noise signals, PA-generated noise signals, etc.) through the isolation circuitry  26 . The LNA  80  may additionally or alternatively receive a leakage signal or current associated with the TX circuitry  52  sending the TX signal (e.g., a portion of the TX signal that leaks from the one or more antennas  20 ). The LNA  80  may amplify the RX signal to a suitable level for the rest of the circuitry to process. However, the LNA  80  may also amplify the other received signals (e.g., noise signals, PA-generated noise signals, etc.). As such, the demodulator  82  may receive the amplified RX signal with amplified noise and/or leakage signals, which may interfere with the RX signal and result in reduced signal integrity. Embodiments are described below that reduce and/or compensate for the noise and/or leakage signals generated by the TX circuitry  52  and arriving at the RX circuitry  54  to prevent disruption of RX signals. Specifically, a noise canceller signal and/or leakage canceller signal may be generated at the TX circuitry  52  and provided via one or more feedback paths to the RX circuitry  54 . 
     With the foregoing in mind,  FIG.  9    is a schematic diagram of at least a portion of example transceiver circuitry  29  associated with  FIG.  7   , according to an embodiment of the present disclosure. Specifically,  FIG.  9    depicts a TX signal  92  generated and sent from the TX circuitry  52 , through a duplexer  57 A of the isolation circuitry  26 , to the one or more antennas  20  for transmission. Moreover, the RX circuitry  54  may receive an RX signal  94  via the one or more antennas  20  through a duplexer  57 B of the isolation circuitry  26  to reach the RX circuitry  54  for reception. The isolation circuitry  26 , including the two duplexers  57 A and  57 B, may be referred to as an electrical balanced duplexer (EBD). The duplexer  57 B may block the TX signal  92  from the RX circuitry  54 . Moreover, the duplexer  57 A may block the RX signal  94  from the TX circuitry  52 . As such, the duplexer  57 A and the duplexer  57 B may facilitate bidirectional communication of the TX signal  92  and the RX signal  94  over a shared path  96  using FDD techniques. It should be appreciated that  FIG.  9    depicts an example embodiment of the isolation circuitry  26 , and different circuitry, electrical components, and/or techniques may be used in other embodiments to provide isolation between the TX signal  92  and the RX circuitry  54  and/or the RX signal  94  and the TX circuitry  52 . 
     The duplexer  57 A may include tunable impedance components, such as a transmitter impedance gradient (TX IG)  102  and a transmitter impedance tuner (TX IT)  104 , to facilitate transmission of the TX signal  92  while providing electrical isolation from signals outside the TX frequency band. In specific embodiments, the TX IG  102  and the TX IT  104  may provide unbalanced and unmatched impedance with respect to signals within the TX frequency band to enable such signals to pass through. For example, the TX IG  102  may provide a low impedance and the TX IT  104  may provide a high impedance. This unbalanced impedance state may enable the TX signals (e.g., the TX signal  92 ) to travel from the TX circuitry  52  across the first balun  98  to the shared path  96 . Moreover, the TX IG  102  and the TX IT  104  may provide balanced and matched impedance with respect to signals outside the TX frequency band to prevent such signals from passing through. For example, the TX IG  102  and the TX IT  104  may both provide a high impedance with respect to signals outside the TX frequency band. As such, this balanced impedance state may prevent signals outside the TX frequency band (e.g., within the RX frequency band) from traveling from the first balun  98  to the TX circuitry  52 . It should be understood that the TX IG  102  and the TX IT  104  are provided as examples, and any suitable tunable impedance components may be used. 
     Similarly, the duplexer  57 B may provide electrical isolation for signals outside the RX frequency band. That is, the duplexer  57 B may enable the RX signal  94 , within the RX frequency band, to pass through a second balun  100  from the shared path  96  (e.g., received via the one or more antennas  20 ) to the RX circuitry  54  (e.g., input to the LNA  80 ). Moreover, the duplexer  57 B may prevent signals (e.g., currents) outside the RX frequency band from traversing the second balun  100 , thus, isolating the RX circuitry  54  from the TX signal  92  and noise signals, among other things. 
     In particular, the second portion of the duplexer  57 B may include a receiver impedance gradient (RX IG)  106  and a receiver impedance tuner (RX IT)  108  to facilitate reception of the RX signal  94  while providing electrical isolation against signals outside the RX frequency band. In specific embodiments, the RX IG  106  and the RX IT  108  may provide unbalanced and unmatched impedance with respect to signals within the RX frequency band to enable such signals to pass through. For example, with respect to signals within the RX frequency band, the RX IG  106  may provide a low impedance to a first side of the second balun  100  and the RX IT  108  may provide a high impedance to a second side of the second balun  100 . This unbalanced impedance state may enable the RX signals (e.g., the RX signal  94 ) to travel from the one or more antennas  20  across the second balun  100  to the RX circuitry  54 . Additionally, the RX IG  106  and the RX IT  108  may provide balanced and matched impedance with respect to signals outside the RX frequency band (e.g., within the TX frequency band). For example, with respect to signals outside the RX frequency band, the RX IG  106  and the RX IT  108  may both provide a high impedance with respect to signals outside the RX frequency band. This balanced impedance state may prevent signals outside the RX frequency band from traveling from the second balun  100  to the RX circuitry  54 . It should be understood that the RX IG  106  and the RX IT  108  are provided as examples, and any suitable tunable impedance components may be used. 
     However, the electrical isolation between the TX signal  92  and the RX circuitry  54  may benefit from additional electrical isolation. In particular, because the isolation provided by the duplexers  57 A and  57 B may be non-ideal (e.g., limited in real-world conditions or when implemented) when transmitting the TX signal  92 , a portion of the TX signal (e.g., a leakage current or signal) may leak to the RX circuitry  54 . That is, the RX IG  106  and/or the RX IT  108  may include less than ideal electrical characteristics. Hence, the RX IG  106  and the RX IT  108  may experience at least some or partially unbalanced (e.g., and/or unmatched) impedances, which may cause leakage of some electrical current associated with the TX signal  92  to the RX circuitry  54 . Moreover, the second portion of the duplexer  57 B is susceptible to noise signals within the RX frequency band. For example, the PA  70 , when amplifying the TX signal for transmission with sufficient electrical power, may introduce noise signals (e.g., including in the RX frequency range) to the TX signal  92  that may traverse the first balun  98  and the second balun  100  and cause interference with the RX signal  94 . To reduce or cancel the leakage and/or noise signals, a noise canceller signal and/or leakage canceller signal may be generated at the TX circuitry  52  and provided via one or more feedback paths to the RX circuitry  54 , as discussed in more detail below. This may result in additional or better isolation for the RX circuitry  54  from the TX signal  92 . 
       FIG.  10    is a schematic diagram of a first embodiment of the transceiver circuitry  29  of  FIG.  9    including a feedback path  110  electrically coupled to an input of the PA  70  that provides a leakage canceller signal  112  (e.g., a feedback signal) to cancel or reduce a leakage signal  116  of the TX signal  92 . In particular, the TX circuitry  52  may generate and send the TX signal  92  within the TX frequency band to be transmitted using the one or more antennas  20 . The PA  70  may amplify the TX signal  92  and the TX signal  92  may pass through the first balun  98  and the shared signal path  96  for transmission via the antennas  20 . 
     The second balun  100  may prevent the TX signal  92  to pass through to the RX circuitry  54  from the shared signal path  96 . However, due to real-world variations in electrical characteristics of different electrical components, such as the second balun  100 , the RX IG  106 , and/or the RX IT  108 , a portion of the TX signal  92  (e.g., a leakage current or signal  116 ) may leak from the shared signal path  96  to the second balun  100 . If not accounted for, the leakage signal  116  may cause sensitivity degradation at the RX circuitry  54  and/or interfere with an RX signal  94  received at the RX circuitry  54 . 
     As mentioned above, the feedback path  110  may provide the leakage canceller signal  112  to reduce or cancel the leakage signal  116 . The feedback path  110  may be electrically coupled to an input of the PA  70  at a node  114  (e.g., between the modulator  72  and the PA  70 ) to provide the leakage canceller signal  112 . As such, the transceiver circuitry  29  may include circuitry on the feedback path  110  to facilitate cancelling the leakage signal  116   
     In some embodiments, the feedback path  110  may include phase adjustment circuitry  118  and gain adjustment circuitry  120  to facilitate cancelling the leakage signal  116 . The phase adjustment circuitry  118  may adjust a phase of the leakage canceller signal  112 . For example, the feedback path  110  may use the phase adjustment circuitry to provide the leakage canceller signal  112 , 180 degrees out of phase compared to the TX signal  92  to cancel the leakage signal  116 . In some embodiments, the transceiver circuitry  29  may include phase sensing circuitry to determine the phase of the TX signal  92 , so that the phase adjustment circuitry  118  may better tune the phase of the leakage canceller signal  112  to be 180 degrees out of phase compared to the TX signal  92 . 
     Moreover, the gain adjustment circuitry  120  may adjust an amplitude of the leakage canceller signal  112  to correlate to or match the amplitude of the leakage signal  116  to reduce or cancel the leakage signal  116 . In some embodiments, the transceiver circuitry  29  may include gain or amplitude sensing circuitry to determine the amplitude of the leakage signal  116 , so that the gain adjustment circuitry  120  may better tune the amplitude of the leakage canceller signal  112  to correlate to or match the amplitude of the leakage signal  116 . As such, the feedback path  110  may provide the leakage canceller signal  112  to the RX circuitry  54  to reduce or compensate for an effect of the leakage signal  116  on RX signals. 
       FIG.  11    is a schematic diagram of a second embodiment of the transceiver circuitry  29  of  FIG.  9    including a feedback path  111  electrically coupled to an output of the PA  70 . The feedback path  111  may provide the leakage canceller signal  112  (e.g., a leakage canceller signal) to cancel or reduce the leakage signal  116  from the TX signal  92 . As previously discussed, the PA  70  may amplify the TX signal  92  and the amplified TX signal  92  may pass through the first balun  98  and the shared signal path  96  for transmission via the one or more antennas  20 . Because the feedback path  111  is coupled to the output of the PA  70 , the leakage canceller signal  112  may include noise (e.g., outside of the TX frequency band, such as within the RX frequency band) generated by the PA  70 . As such, the transceiver circuitry  29  may include circuitry on the feedback path  111  to filter such noise from the leakage canceller signal  112 , such that the leakage canceller signal  112  may better correlate to and compensate for the TX signal  92 . 
     As illustrated, the feedback path  111  includes, in addition to the phase adjustment circuitry  118  and the gain adjustment circuitry  120 , a band pass filter (BPF)  130 . The BPF  130  may enable TX frequency band signals to pass through, and block signals outside of the TX frequency band from passing through. As such, the BPF  130  may facilitate cancelling the leakage signal  116  at the RX circuitry  54 . As with the transceiver circuitry  29  described in  FIG.  10   , the phase adjustment circuitry  118  may adjust a phase of the leakage canceller signal  112  to correlate to (e.g., 180 degree out of phase compared to) a phase of the leakage signal  116 . Moreover, gain adjustment circuitry  120  may adjust an amplitude of the leakage canceller signal  112  to correlate to or match the amplitude of the leakage signal  116 . As such, the feedback path  111  may provide the leakage canceller signal  112  to the RX circuitry  54  to reduce an effect of the leakage signal  116 . It should be understood that because the transceiver circuitry  29  of  FIG.  10    couples the feedback path  110  to an input of the PA  70  (rather than an output of the PA  70 ), the noise generated by the PA  70  may not be included in the leakage canceller signal  112 , and, as such, the BPF  130  may be unnecessary in that embodiment. 
       FIG.  12    is a schematic diagram of a third embodiment of the transceiver circuitry  29  of  FIG.  9    including a feedback path  140  electrically coupled to an output of the PA  70  that provides a noise canceller signal  142  (e.g., a feedback signal) to cancel or reduce a noise signal  143  generated by the PA  70 . As previously discussed, the PA  70  may amplify the TX signal  92  with sufficient power for transmission via the antennas  20 . However, in operation, the PA  70  may generate a noise signal  143  within the RX frequency band, which may pass through the isolation circuitry  26  (e.g., including the first balun  98  and the second balun  100 ) and arrive at the RX circuitry  54 . For example, the noise signal  143  may be a result of non-linear characteristics of the PA  70 . To compensate for or reduce the noise signal  143 , the feedback path  140  may include circuitry to generate the noise canceller signal  142 . 
     The feedback path  140  may include phase adjustment circuitry  118 , gain adjustment circuitry  120 , and a BPF  144 . The phase adjustment circuitry  118  may adjust a phase of the noise canceller signal  142  to be 180 degree out of phase from the noise signal  143 . In some embodiments, the transceiver circuitry  29  may include phase sensing circuitry to determine the phase of the noise signal  143 , so that the phase adjustment circuitry  118  may better tune the phase of the noise canceller signal  142  to be 180 degrees out of phase compared to the noise signal  143 . Moreover, the gain adjustment circuitry  120  may adjust an amplitude of the noise canceller signal  142  to correlate to or match the amplitude of the noise signal  143  to reduce or cancel the noise signal  143 . In some embodiments, the transceiver circuitry  29  may include gain or amplitude sensing circuitry to determine the amplitude of the noise signal  143 , so that the gain adjustment circuitry  120  may better tune the amplitude of the noise canceller signal  142  to correlate to or match the amplitude of the noise signal  143 . As such, the feedback path  140  may provide the noise canceller signal  142  to the RX circuitry  54  to reduce or compensate for an effect of the noise signal  143  on RX signals. 
       FIG.  13    is a circuit diagram of an implementation of the second and third embodiments of the transceiver circuitry  29  as illustrated in  FIGS.  11  and  12   , according to embodiments of the present disclosure. In particular, additional isolation circuitry  146  (e.g., in addition to the isolation circuitry  26 ) may be disposed on feedback paths  111 ,  140 . The feedback paths  111 ,  140  may each electrically couple to the TX circuitry  52  at the output of the PA  70  (e.g., between the output of the PA  70  and the isolation circuitry  26 ) such that they may split from a node  129 . 
     The TX IG  102  and the TX IT  104  may include unmatched impedance with respect to signals within the TX frequency band. As such, a TX signal may traverse the first balun  98  to the shared signal path  96  for transmission by the one or more antennas  20 . However, due to real-world deficiencies in the RX IG  106 , the RX IT  108 , and/or the second balun  100 , among other components, a portion of the TX signal (e.g., a leakage signal  116 ) may leak to the RX circuitry  54  (instead of being transmitted via the one or more antennas  20 ). If left uncompensated, the leakage signal  116  may desense the RX circuitry  54  and/or interfere with RX signals received at the RX circuitry  54 . Moreover the PA  70  of the TX circuitry  52  may generate a noise signal  143  due to non-linear characteristics of the PA  70 . Such noise signals may be distributed across a wide frequency range. If left uncompensated, the noise signal  143  within the RX frequency range may traverse through the first balun  98  and the second balun  100  and may desense the RX circuitry  54 . 
     As such, the feedback path  111  may provide the leakage canceller signal  112  to cancel the leakage signal  116  of the TX signal and the feedback path  140  may provide the noise canceller signal  142  to cancel the noise signal  143  generated by the PA  70 . In particular, the feedback path  111  may include the phase adjustment circuitry  118  that enables adjusting the phase of the leakage canceller signal  112  to be 180 degrees out of phase with respect to the leakage signal  116 , the gain adjustment circuitry  120  that enables adjusting the amplitude of the leakage canceller signal  112  to correlate to the amplitude of the leakage signal  116 , and the BPF  130  that filters out signals with frequencies outside of the TX frequency band. In some embodiments, the BPF  130  may include a balun with respective IG and IT components to enable signals within the TX frequency band to pass through and prevent signals outside the TX frequency band from passing through. As such, the leakage canceller signal  112  traversing the feedback path  111  may cancel the leakage signal  116  of the TX signal. 
     Moreover, the feedback path  140  may include the phase adjustment circuitry  118  that enables adjusting the phase of the noise canceller signal  142  to be 180 degrees out of phase with respect to the noise signal  143 , the gain adjustment circuitry  120  that enables adjusting the amplitude of the noise canceller signal  142  to correlate to the amplitude of the noise signal  143 , and the BPF  144  that filters out signals with frequencies outside of the RX frequency band. In some embodiments, the BPF  144  may include a balun with respective IG and IT components to enable signals within the RX frequency band to pass through and prevent signals outside the RX frequency band from passing through. As such, the noise canceller signal  142  traversing the feedback path  140  may cancel the noise signal  143  generated by the PA  70 . 
       FIG.  14    is a circuit diagram of another example of the transceiver circuitry  29  of the electronic device of  FIG.  1   . Additional isolation circuitry  156  may include the first embodiment and the third embodiment of the transceiver circuitry  29 , as described above, to provide the leakage canceller signal  112  and the noise canceller signal  142 . The additional isolation circuitry  156  may use the feedback path  110  and the feedback path  140 . The feedback path  110  may couple the input of PA  70  and the feedback path  140  may couple the output of the PA  70  (e.g., before the isolation circuitry  26 ). It should be understood that because the transceiver circuitry  29  of  FIG.  14    couples the feedback path  110  to an input of the PA  70 , the noise generated by the PA  70  may not be included in the leakage canceller signal  112 , and, as such, the BPF  130  may be unnecessary in this embodiment. 
     Similar to the example of  FIG.  13   , the TX IG  102  and the TX IT  104  may include unmatched (and unbalanced) impedance with respect to signals within the TX frequency band. As such, a TX signal may traverse the first balun  98  to the shared signal path  96  for transmission by the antennas  20 . However, due to real-world deficiencies in characteristics of the RX IG  106 , the RX IT  108 , the second balun  100 , among other possibilities, the second balun  100  may leak a portion of the TX signal to the LNA  80  and the RX circuitry. The leakage signal (e.g., leakage signal  116 ) may desense the RX circuitry and cause interference when receiving RX signals. Moreover, the PA  70  of the TX circuitry may generate noise signals, for example, due to non-linear characteristic of the PA  70 . Such noise signals may dissipate across a wide frequency range. A portion of the noise signals that are within the RX frequency range may traverse through the first balun  98  and the second balun  100  and may desense the RX circuitry. 
     As such, the feedback path  110  may provide the leakage canceller signal  112  (not shown in  FIG.  13   ) to cancel the leakage current (e.g., leakage signal  116 ) of TX signal and the feedback path  140  may provide the noise canceller signal  142  to cancel the noise signals (e.g., noise signals  143 ) before the LNA  80  of the RX circuitry  54 . In particular, the feedback path  110  may include the phase adjustment circuitry  118  that enables adjusting the phase of the leakage canceller signal  112  to be 180 degrees out of phase with respect to the leakage signal  116 , the gain adjustment circuitry  120  that enables adjusting the amplitude of the leakage canceller signal  112  to correlate to the amplitude of the leakage signal  116 . Since feedback path  110  is electrically coupled to the input of the PA  70 , the leakage canceller signal  112  may include TX signals within TX frequency band. 
     Moreover, the feedback path  140  may include the gain adjustment circuitry  120 , the BPF  144 , and the phase adjustment circuitry  118 . In some embodiments, the BPF  144  may include a balun with respective IG and IT components to provide signals within the RX frequency band from the TX circuitry to the RX circuitry. As such, the feedback path  140  may cancel the noise signals in the RX circuitry by providing the second feedback signal  142  using the gain adjustment circuitry  120 , the BPF  144 , and the phase adjustment circuitry  118 . 
     The techniques presented and claimed herein are referenced and applied to material objects and concrete examples of a practical nature that demonstrably improve the present technical field and, as such, are not abstract, intangible or purely theoretical. Further, if any claims appended to the end of this specification contain one or more elements designated as “means for [perform]ing [a function] . . . ” or “step for [perform]ing [a function] . . . ,” it is intended that such elements are to be interpreted under 35 U.S.C. 112(f). However, for any claims containing elements designated in any other manner, it is intended that such elements are not to be interpreted under 35 U.S.C. 112(f).

Metadata:
Filing Date: 20220603
Publication Date: 20230418
Grant Date: 20230418
Priority Date: 20201007
Inventors: MUHAREMOVIC, NEDIM
HUR, JOONHOI
VAZNY, RASTISLAV
Assignee: APPLE INC
CPC Classifications: [{"code": "H04B1/525", "inventive": true, "first": true, "tree": "[]"}, {"code": "H03H7/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B17/354", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/0067", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/525", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B1/0475", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/0067", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L5/1461", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L5/1461", "inventive": true, "first": true, "tree": "[]"}, {"code": "H03H11/32", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/0067", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B17/104", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B17/104", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/0067", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L5/1461", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 80738530