PATENT DOCUMENT

Publication Number: US-9763195-B2
Application Number: US-201514601935-A
Country: US
Kind Code: B2

Title: Dynamic envelope elimination and restoration polar transmitter

Abstract:
Devices and methods for increasing and maximizing power efficiency in polar and Cartesian transmitters are provided. By way of example, an electronic device includes a transmitter configured to receive an in-phase/quadrature (I/Q) signal, generate an amplitude envelope signal based on the I/Q signal, decompose the amplitude envelope signal into an envelope amplitude portion and an envelope phase portion, and to dynamically switch between performing a polar modulation of the I/Q signal and performing an I/Q modulation of the I/Q signal based at least in part on an amplitude value of the envelope phase portion.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a transmitter comprising:
 a modulator configured to receive an in-phase/quadrature (I/Q) signal and generate an amplitude envelope signal based on the I/Q signal; and 
 an envelope splitter configured to decompose the amplitude envelope signal into an envelope amplitude portion and an envelope phase portion, wherein the transmitter is configured to dynamically switch between performing a polar modulation of the I/Q signal and performing an I/Q modulation of the I/Q signal based at least in part on an amplitude value of the envelope phase portion. 
 
 
     
     
       2. The electronic device of  claim 1 , wherein the amplitude envelope signal comprises a function of the I/Q signal. 
     
     
       3. The electronic device of  claim 1 , wherein the transmitter comprises an I/Q transmitter. 
     
     
       4. The electronic device of  claim 1 , wherein the transmitter comprises an envelope elimination and restoration (EER) polar transmitter. 
     
     
       5. The electronic device of  claim 1 , wherein the transmitter is configured to perform the polar modulation of the I/Q signal when the amplitude value is approximately equal to an amplitude threshold value. 
     
     
       6. The electronic device of  claim 1 , wherein the transmitter is configured to perform the I/Q modulation of the I/Q signal when the amplitude value decreases below an amplitude threshold value. 
     
     
       7. The electronic device of  claim 6 , wherein the transmitter is configured to switch from performing the I/Q modulation of the I/Q signal to performing the polar modulation of the I/Q signal when the amplitude value returns to the amplitude threshold value. 
     
     
       8. The electronic device of  claim 1 , wherein the transmitter is configured to dynamically switch between performing the polar modulation of the I/Q signal and performing the I/Q modulation of the I/Q signal to increase a power efficiency of the transmitter. 
     
     
       9. The electronic device of  claim 1 , wherein the transmitter is configured to support Bluetooth® Enhanced Data Rate 3.0 (EDR3) or higher. 
     
     
       10. A method, comprising:
 receiving an in-phase/quadrature (I/Q) representation of a data signal via a dynamic envelope elimination and restoration (EER) polar transmitter; 
 generating an amplitude envelope signal based on the data signal; 
 decomposing the amplitude envelope signal into an envelope amplitude subcomponent and an envelope phase subcomponent; and 
 dynamically switching between performing an EER polar modulation and performing an I/Q modulation of the data signal based at least in part on whether the envelope phase subcomponent is substantially equal to a first amplitude value or a second amplitude value. 
 
     
     
       11. The method of  claim 10 , wherein dynamically switching between performing the EER polar modulation and performing the I/Q modulation of the data signal comprises alternating between operating as an EER polar transmitter and operating as an I/Q transmitter. 
     
     
       12. The method of  claim 10 , wherein performing the EER polar modulation of the data signal comprises performing the EER polar modulation of the data signal only when the envelope phase subcomponent is substantially equal to or greater than an amplitude threshold value as the first amplitude value. 
     
     
       13. The method of  claim 10 , wherein dynamically switching between performing the EER polar modulation and performing the I/Q modulation comprises alternately switching between performing the EER polar modulation and performing the I/Q modulation over a period of time. 
     
     
       14. A method for increasing a power efficiency of an electronic transmitter, comprising:
 receiving an amplitude envelope signal via a processor of the electronic transmitter; 
 splitting the amplitude envelope signal into an envelope amplitude portion and an envelope phase portion; 
 controlling the electronic transmitter to operate as a polar transmitter during a first time period; 
 controlling the electronic transmitter to operate as an in-phase/quadrature (I/Q) transmitter during a second time period, wherein the second time period corresponds to a period in which the envelope phase portion of the amplitude envelope signal approaches a zero crossing; and 
 controlling the electronic transmitter to revert to operating as the polar transmitter during a third time period. 
 
     
     
       15. The method of  claim 14 , wherein receiving the amplitude envelope signal comprises receiving a time-domain amplitude envelope signal expressed as: A(t)=√{square root over (I 2 +Q 2 )} or A(t)=√{square root over (I(t) 2 +Q(t) 2 )}, wherein A(t) comprises the amplitude envelope signal, and wherein I comprises an in-phase component of a data signal and Q comprises an quadrature component of the data signal. 
     
     
       16. The method of  claim 14 , wherein splitting the amplitude envelope signal into the envelope amplitude portion and the envelope phase portion comprises:
 transforming the amplitude envelope signal into a digital domain; and 
 splitting the envelope amplitude portion and the envelope phase portion into a digital domain representation of the envelope amplitude portion and a digital domain representation of the envelope phase portion expressed as: A=A a ·A p . 
 
     
     
       17. The method of  claim 14 , wherein controlling the electronic transmitter to operate as the polar transmitter during the first time period comprises controlling the electronic transmitter to operate as an envelope elimination and restoration (EER) polar transmitter during the first time period. 
     
     
       18. The method of  claim 14 , wherein controlling the electronic transmitter to operate as the I/Q transmitter during the second time period comprises controlling the electronic transmitter to operate as the I/Q transmitter when the amplitude envelope signal approaches the zero crossing. 
     
     
       19. The method of  claim 14 , wherein controlling the electronic transmitter to operate as the polar transmitter during the first time period comprises controlling the electronic transmitter to operate as the polar transmitter when an amplitude of the envelope phase portion is approximately equal to or greater than a predetermined threshold value. 
     
     
       20. The method of  claim 14 , wherein controlling the electronic transmitter to operate as the I/Q transmitter during the second time period comprises controlling the electronic transmitter to operate as the I/Q transmitter when an amplitude of the envelope phase portion decreases to a value below a predetermined threshold value. 
     
     
       21. The method of  claim 14 , wherein controlling the electronic transmitter to revert to operating as the polar transmitter during the third time period comprises controlling the electronic transmitter to operate as the polar transmitter after a point at which the envelope phase portion traverses the zero crossing. 
     
     
       22. An electronic transmitter, comprising:
 a modulator configured to receive an in-phase/quadrature (I/Q) signal input and to modulate the I/Q signal input; 
 a dynamic envelope splitter configured to:
 receive an extracted amplitude envelope of the I/Q signal input; 
 decompose the amplitude envelope into an amplitude subcomponent signal and a phase subcomponent signal; 
 provide the phase subcomponent signal to a phase path of the electronic transmitter when the phase subcomponent signal comprises an amplitude value equal to a threshold amplitude value as an indication to operate the electronic transmitter as an envelope elimination and restoration (EER) polar transmitter; and 
 provide the amplitude subcomponent signal to an amplitude path of the electronic transmitter when the amplitude subcomponent signal comprises an amplitude value equal to or less than the threshold amplitude value as an indication to operate the electronic transmitter as an I/Q transmitter; and 
 
 an amplifier configured to generate an electromagnetic signal for transmission based at least in part on the amplitude subcomponent signal or the phase subcomponent signal. 
 
     
     
       23. The electronic device of  claim 22 , wherein the threshold amplitude value comprises an amplitude value of approximately 1 volt (V). 
     
     
       24. A non-transitory computer-readable medium having computer executable code stored thereon, the code comprising instructions to:
 derive an amplitude envelope based on a received Cartesian coordinate based data signal; 
 decompose the amplitude envelope into an envelope amplitude portion and an envelope phase portion; and 
 cause a transmitter to alternately transition between computing a polar modulation of the Cartesian coordinate based data signal and computing a Cartesian modulation of the Cartesian coordinate based data signal based at least in part on an amplitude value of the envelope phase portion.

Description:
BACKGROUND 
     The present disclosure relates generally to Cartesian and polar transmitters, and more particularly, to Cartesian and polar transmitters included within electronic 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. 
     Transmitters and receivers are commonly included in various electronic devices, and particularly, portable electronic devices such as, for examples, phones (e.g., mobile and cellular phones, cordless phones, personal assistance devices), computers (e.g., laptops, tablet computers), internet connectivity routers (e.g., Wi-Fi routers or modems), radios, televisions, or any of various other stationary or handheld devices. One type of transmitter, known as a wireless transmitter, may be used to generate a wireless signal to be transmitted by way of an antenna coupled to the transmitter. Specifically, the wireless transmitter is generally used to wirelessly communicate data over a network channel or other medium (e.g., air) to one or more receiving devices. 
     The wireless transmitters may generally include subcomponents such as, for example, an oscillator, a modulator, one or more filters, and a power amplifier. Furthermore certain data modulation techniques that may be implemented by wireless transmitters may include a modulation of in-phase (I)/quadrature (Q) time samples of a signal into amplitude and phase signals. However, because the modulation from the I/Q samples to the amplitude and phase signals may be based on a nonlinear function, the amplitude and phase may include a very wide bandwidth (e.g., infinite bandwidth), and may thus include a number of nonlinearities or distortions upon completion of the modulation. Moreover, even when the amplitude and phase are filtered in an attempt to track the bandwidth or envelope of the amplitude and phase, the filtering may cause the amplitude and/or phase to no longer include a constant envelope, and to include undesirable spikes in amplitude at or near the zero crossing or zero value. These undesirable qualities may contribute to power efficiency losses in the wireless transmitters, and, by extension, may contribute to increased power consumption by the wireless transmitters. It may be useful to provide more advanced and improved wireless transmitters. 
     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. 
     Various embodiments of the present disclosure may be useful in increasing and maximizing power efficiency in polar and Cartesian transmitters. By way of example, an electronic device includes a transmitter configured to receive an in-phase/quadrature (I/Q) signal, generate an amplitude envelope signal based on the I/Q signal, decompose the amplitude signal into an envelope amplitude portion and an envelope phase portion, and to dynamically switch between performing a polar modulation of the I/Q signal and performing an I/Q modulation of the I/Q signal based at least in part on an amplitude value of the envelope phase portion. 
     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 in which: 
         FIG. 1  is a schematic block diagram of an electronic device including a transceiver, in accordance with an embodiment; 
         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 hand-held device representing another embodiment of the electronic device of  FIG. 1 ; 
         FIG. 4  is a front view of another hand-held 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 front view of a wearable electronic device representing another embodiment of the electronic device of  FIG. 1 ; 
         FIG. 7  is a block diagram of a transmitter of the transceiver included within the electronic device of  FIG. 1 , in accordance with an embodiment; 
         FIG. 8  is a block diagram of the transmitter of  FIG. 7  and including a dynamic envelope splitter, in accordance with an embodiment; 
         FIG. 9  is a diagram of an amplitude envelope signal, an amplitude portion of the amplitude envelope signal, and a phase portion of the amplitude envelope signal, in accordance with an embodiment; 
         FIG. 10  is a flow diagram illustrating an embodiment of a process useful in dynamically switching between operating as an envelope elimination and restoration (EER) polar transmitter and an in-phase/quadrature (I/Q) transmitter, in accordance with an embodiment; and 
         FIG. 11  is a plot diagram illustrating the performance of a dynamic EER polar transmitter as compared to a lesser advanced polar transmitter, in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     One or more specific embodiments of the present disclosure will be described below. These described embodiments are only examples of the presently disclosed techniques. Additionally, in an effort to provide a concise description of these embodiments, all features of an actual implementation may not be 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. 
     Embodiments of the present disclosure relate to techniques for increasing and maximizing power efficiency in polar and Cartesian transmitters. For example, the present embodiments may include providing a dynamic Kahn envelope elimination and restoration (EER) polar transmitter, which may include a modulator (e.g., digital signal processor (DSP), coordinate rotation digital computer (CORDIC) processor) and a dynamic envelope splitter (e.g., DSP) that may be used to extract the information of an incoming in-phase/quadrature (I/Q) component signal, and to determine whether to perform an EER polar modulation of the incoming signal, an I/Q modulation of the incoming signal, or both in conjunction. Indeed, the dynamic envelope splitter may be useful in allowing the transmitter to dynamically switch the transmitter between operating as an EER polar transmitter operating as an I/Q transmitter based on amplitude envelop information (e.g., amplitude and/o phase information) of the incoming I/Q data signal extracted from the amplitude envelope generated by the polar modulator. In this way, the power efficiency of the transmitter in modulating data signals and/or carrier frequency signals may be markedly increased and maximized. Furthermore, the alignment between amplitude and phase path sensitivity and power amplifier input and output leakage may also be improved utilizing presently disclosed techniques. 
     With the foregoing in mind, a general description of suitable electronic devices that may employ polar and Cartesian transmitters and are useful in dynamically switching transmitters between operating as envelope elimination and restoration (EER) polar transmitters and in-phase/quadrature (I/Q) transmitters will be provided below. Turning first to  FIG. 1 , an electronic device  10  according to an embodiment of the present disclosure may include, among other things, one or more processor(s)  12 , memory  14 , nonvolatile storage  16 , a display  18  input structures  22 , an input/output (I/O) interface  24 , network interfaces  26 , a transceiver  28 , and a power source  29 . 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 desktop computer depicted in  FIG. 4 , the wearable electronic device depicted in  FIG. 5 , or similar devices. It should be noted that the processor(s)  12  and/or other data processing circuitry may be generally referred to herein as “data processing circuitry.” Such data processing circuitry may be embodied wholly or in part as software, firmware, hardware, or any combination thereof. Furthermore, the data processing circuitry 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  and/or other data processing circuitry may be operably coupled with the memory  14  and the nonvolatile memory  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 at least collectively storing the instructions or routines, such as the memory  14  and the nonvolatile storage  16 . 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. Also, 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 allow users to view images generated on the electronic device  10 . In some embodiments, the display  18  may include a touch screen, which may allow users to interact 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 organic light emitting diode (OLED) displays, or some combination of LCD panels and OLED panels. 
     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 interfaces  26 . The network interfaces  26  may include, for example, 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, 4 th  generation (4G) cellular network, or long term evolution (LTE) cellular network. The network interface  26  may also include interfaces for, for example, broadband fixed wireless access networks (WiMAX), mobile broadband Wireless networks (mobile WiMAX), asynchronous digital subscriber lines (e.g., ADSL, VDSL), digital video broadcasting-terrestrial (DVB-T) and its extension DVB Handheld (DVB-H), ultra Wideband (UWB), alternating current (AC) power lines, and so forth. 
     In certain embodiments, to allow the electronic device  10  to communicate over the aforementioned wireless networks (e.g., Wi-Fi, WiMAX, Mobil WiMAX, 4G, LTE, and so forth), the electronic device  10  may include a transceiver  28 . The transceiver  28  may include any circuitry the may be useful in both wirelessly receiving and wirelessly transmitting signals (e.g., data signals). Indeed, in some embodiments, as will be further appreciated, the transceiver  28  may include a transmitter and a receiver combined into a single unit, or, in other embodiments, the transceiver  28  may include a transmitter separate from the receiver. For example, as noted above, the transceiver  28  may transmit and receive signals (e.g., data symbols) to support 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, and LTE 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 a power source  29 . The power source  29  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 include computers that are generally portable (such as laptop, notebook, and tablet computers) as well as computers that are 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. By way of example, the electronic device  10 , taking the form of a notebook computer  30 A, is illustrated in  FIG. 2  in accordance with one embodiment of the present disclosure. The depicted computer  30 A may include a housing or enclosure  32 , 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  30 A, such as to start, control, or operate a GUI or applications running on computer  30 A. For example, a keyboard and/or touchpad may allow a user to navigate a user interface or application interface displayed on display  18 . 
       FIG. 3  depicts a front view of a handheld device  30 B, which represents one embodiment of the electronic device  10 . The handheld device  34  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  34  may be a model of an iPod® or iPhone® available from Apple Inc. of Cupertino, Calif. 
     The handheld device  30 B may include an enclosure  36  to protect interior components from physical damage and to shield them from electromagnetic interference. The enclosure  36  may surround the display  18 , which may display indicator icons  39 . The indicator icons  39  may indicate, among other things, a cellular signal strength, Bluetooth connection, and/or battery life. The I/O interfaces  24  may open through the enclosure  36  and may include, for example, an I/O port for a hard wired connection for charging and/or content manipulation using a standard connector and protocol, such as the Lightning connector provided by Apple Inc., a universal service bus (USB), or other similar connector and protocol. 
     User input structures  42 , in combination with the display  18 , may allow a user to control the handheld device  30 B. For example, the input structure  40  may activate or deactivate the handheld device  30 B, the input structure  42  may navigate user interface to a home screen, a user-configurable application screen, and/or activate a voice-recognition feature of the handheld device  30 B, the input structures  42  may provide volume control, or may toggle between vibrate and ring modes. The input structures  42  may also include a microphone may obtain a user&#39;s voice for various voice-related features, and a speaker may enable audio playback and/or certain phone capabilities. The input structures  42  may also include a headphone input may provide a connection to external speakers and/or headphones. 
       FIG. 4  depicts a front view of another handheld device  30 C, which represents another embodiment of the electronic device  10 . The handheld device  30 C may represent, for example, a tablet computer, or one of various portable computing devices. By way of example, the handheld device  30 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  30 D may represent another embodiment of the electronic device  10  of  FIG. 1 . The computer  30 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  30 D may be an iMac®, a MacBook®, or other similar device by Apple Inc. It should be noted that the computer  30 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  30 D such as the dual-layer display  18 . In certain embodiments, a user of the computer  30 D may interact with the computer  30 D using various peripheral input devices, such as the keyboard  22  or mouse  38 , which may connect to the computer  30 D via a wired and/or wireless I/O interface  24 . 
     Similarly,  FIG. 6  depicts a wearable electronic device  30 E representing another embodiment of the electronic device  10  of  FIG. 1  that may be configured to operate using the techniques described herein. By way of example, the wearable electronic device  30 E, which may include a wristband  43 , may be an Apple Watch® by Apple, Inc. However, in other embodiments, the wearable electronic device  30 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  30 E may include a touch screen (e.g., LCD, OLED display, active-matrix organic light emitting diode (AMOLED) display, and so forth), which may allow users to interact with a user interface of the wearable electronic device  30 E. 
     In certain embodiments, as previously noted above, each embodiment (e.g., notebook computer  30 A, handheld device  30 B, handheld device  30 C, computer  30 D, and wearable electronic device  30 E) of the electronic device  10  may include a transceiver  28 , which may include a dynamic Kahn envelope elimination and restoration (EER) polar transmitter (e.g., transmitter  77  as will be discussed with respect to  FIG. 8 ). Indeed, as will be further appreciated, the transmitter may include a modulator (e.g., digital signal processor (DSP), coordinate rotation digital computer (CORDIC) processor) and a dynamic envelope splitter (e.g., DSP) that may be used to extract the information of an incoming in-phase/quadrature (I/Q) component signal (e.g., Cartesian coordinates representation of an incoming data signal), and to determine whether to perform an EER polar modulation of the incoming signal, an I/Q modulation of the incoming signal, or both in conjunction. Indeed, the dynamic envelope splitter may be useful in allowing the transmitter to dynamically switch the transmitter between operating as an EER polar transmitter operating as an I/Q transmitter based on amplitude information (e.g., amplitude and phase information) of the incoming I/Q data signal extracted from the amplitude envelope generated by the polar modulator. In this way, the power efficiency of the transmitter in modulating data signals and/or carrier frequency signals may be markedly increased and maximized. Furthermore, the alignment between amplitude and phase path sensitivity and power amplifier input and output leakage may also be improved utilizing presently disclosed techniques. 
     With the foregoing in mind,  FIG. 7  depicts a transmitter  44  that may be included as part of the transceiver  28 . Although not illustrated, it should be appreciated that the transceiver  28  may also include a receiver that may be coupled to the transmitter  44 . As noted above, and as will be further appreciated with respect to  FIG. 8 , the transmitter  44  may, in some embodiments, include and operate as an EER polar transmitter, while, in other embodiments, the transmitter  44  may include and operate as Cartesian and/or I/Q transmitter. As depicted, the transmitter  44  may receive a signal  45  that may be modulated via a modulator  46 . In certain embodiments, the transmitter  44  may receive a Cartesian coordinate represented signal  45 , which may include, for example, data symbols encoded according to orthogonal in-phase (I) and quadrature (Q) vectors. Thus, when the I/Q signal  45  is converted into an electromagnetic wave (e.g., radio frequency (RF) signal, microwave signal, millimeter wave signal), the conversion may be generally linear, as the I/Q signal may be frequency band-limited. However, in other embodiments, the modulator  46  may be used to translate the I/Q vector components of the signal  45  into a polar coordinate representation of the signal  45 , in which data symbols may be encoded according to an amplitude component and a phase component. 
     In certain embodiments, the modulator  46  may include a digital signal processor (DSP) or a coordinate rotation digital computer (CORDIC) that may be used to process the individual Cartesian represented data symbols (e.g., constellations of data symbols) and/or polar amplitude and phase components of the data symbols. The modulator  46  may also include an envelope limiter and/or envelope detector that may extract amplitude and phase information from the I/Q signal  45 , and may thus generate a constant amplitude envelope signal A(t) (e.g., which may be expressed as: √{square root over (I 2 +Q 2 )} or √{square root over (I(t) 2 +Q(t) 2 )}) in addition to the in-phase (I) signal component (e.g., cos(θ(t))) and the quadrature (Q) signal component (e.g., sin(θ(t))), as illustrated. As further depicted in  FIG. 7 , the transmitter  44  may also include a number of digital-to-analog converters (DACs)  48 ,  50 , and  52  that may be used to respectively convert (e.g., sample) the amplitude envelope signal A(t), the in-phase (I) signal component (e.g., cos(θ(t))), and the quadrature (Q) signal component (e.g., sin(θ(t))) of the signal  45  into digital signals or frequency-domain signals. As further illustrated, the amplitude envelope signal A(t) and the I/Q signals  45  (e.g., signals cos(θ(t)), sin(θ(t))) may be then respectively passed to low pass filters (LPFs)  54 ,  56 , and  58 , which may be provided to pass the low frequency components of the amplitude envelope signal A(t) and the I/Q signals  45  (e.g., signals cos(θ(t)), sin(θ(t))) and filter the high frequency components of the signals. 
     The I/Q signals  45  may be then respectively passed to mixers  60  and  62 . The mixers  60  and  62  may be used to respectively mix (e.g., multiply or upconvert) the frequency of the in-phase (I) signal component (e.g., cos(θ(t))) with the frequency signal of a local oscillator (LO)  64  and the frequency of the quadrature (Q) signal component (e.g., sin(θ(t)) with the frequency signal (e.g., 90° out of phase oscillation signal) of a LO  66  to generate a carrier frequency and/or radio frequency (RF) signal once summed via a summer  68 . The summed in-phase (I) signal component (e.g., cos(θ(t))) and the quadrature (Q) signal component (e.g., sin(θ(t)) may then be passed to a power amplifier (PA)  70  (e.g., high power amplifier (HPA), high efficiency power amplifier (HEPA)) to generate an electromagnetic signal (e.g., radio frequency (RF) signal, microwave signal, millimeter wave signal) for transmission (e.g., via an antenna coupled to the transmitter  44 ). At substantially the same time, the amplitude envelope signal A(t), which, as previously noted, may include a constant amplitude envelope signal (also including signal phase information), may be passed to the PA  70 . In certain embodiments, in accordance with the envelope elimination and restoration technique, the amplitude and phase information of the amplitude envelope signal A(t) may be restored to the envelope of the carrier signal and/or RF signal at the input of the PA  70  to modulate, for example, the supply voltage of the PA  70 . 
     However, in certain embodiments, the amplitude envelope amplitude information and the amplitude envelope phase information may include a very wide frequency bandwidth (e.g., an infinite frequency bandwidth) due to certain discontinuities or nonlinearities in phase (e.g., a distortion of π radians or 180° phase shift) when the phase signal approaches or is at the zero crossing (e.g., the zero value axis of a plot of amplitude envelope). Furthermore, even when the amplitude envelope amplitude and phase portions are filtered (e.g., via baseband filtering) in an attempt to track the envelope amplitude and/or phase portions, the filtering may cause the envelope amplitude and/or phase portions to no longer include a constant envelope, and to include undesirable spikes in amplitude at or near the zero crossing. Still further, merely attempting to track the envelope to regulate power efficiency (e.g., 
               η   =         P   RF       P   DC       ×   100   ⁢   %       ,         
where η is the power efficiency and P is power) of the amplifier  70 , and, by extension, the transmitter  44 , may not compensate for power efficiency losses due to the discontinuities, nonlinearities, or other amplitude spikes in the envelope amplitude and/or phase portions. The foregoing may be especially true for transmitters and/or other wireless systems supporting, for example, Bluetooth® Enhanced Data Rate 3.0 (EDR3) or higher.
 
     Accordingly, in certain embodiments, as illustrated in  FIG. 8 , it may be useful to provide a dynamic EER polar transmitter  72 . As depicted, the dynamic EER polar transmitter  72  may include a dynamic envelop splitter  74 , which may itself include a software system, a hardware system, or some combination of hardware and software (e.g., DSP) that may be implemented as part of one or more processing devices or systems included in the transceiver  28 . Indeed, in certain embodiments, the dynamic envelop splitter  74  that may be used to split the amplitude envelope signal A(t) into an envelope amplitude portion or subcomponent A a (t) and an envelope phase portion or subcomponent A p (t). Specifically, in some embodiments, the amplitude envelope signal A(t) may be expressed as the product of the envelope amplitude portion or subcomponent A a (t) and the envelope phase portion or subcomponent A p (t):A(t)=A a (t)·A p (t). Thus, as further illustrated, the dynamic envelop splitter  74  may allow the dynamic EER polar transmitter  72  to dynamically switch between operating as an EER polar transmitter and operating as an I/Q transmitter based on, for example, the envelope amplitude portion A a (t) and/or the envelope phase portion A p (t) of the amplitude envelope signal A(t). 
     For example, as will be further appreciated with respect  FIG. 9 , based on the respective values of the frequency-domain representations of the envelope amplitude portion A a  and/or the envelope phase portion A p , the dynamic EER polar transmitter  72  may operate as an EER polar transmitter, an I/Q transmitter, or both concurrently, to increase and maximize the power efficiency of the dynamic EER polar transmitter  72 . These techniques may also markedly improve the alignment between amplitude and phase path sensitivity and power amplifier input and output leakage. Particularly, whenever the envelope phase portion A p  decreases below an amplitude threshold value (e.g., an actual or normalized amplitude voltage value) of approximately 1 volt (V), the dynamic EER polar transmitter  72  may transition from operating as an EER polar transmitter to operating as an I/Q transmitter until a point in time at which the envelope phase portion A p  reverts back to an amplitude value equal to or greater than the threshold amplitude value (e.g., approximately 1V or greater than approximately 1V). At such an instance, the dynamic EER polar transmitter  72  may switch back to operating as an EER polar transmitter. It should be appreciated that the amplitude threshold value may include any predetermined amplitude voltage value. 
     For example, in certain embodiments, as further illustrated in  FIG. 8 , when the dynamic EER polar transmitter  72  operates as an I/Q transmitter (e.g., corresponding to a period when A p  decreases to an amplitude value of less than an amplitude threshold value or when 
                   A   a     =       A     A   p       ≈   A       )     ,         
the time-domain representation of the envelope phase portion A p (t) may be mixed (e.g., multiplied) via mixers  75  and  76  with the in-phase (I) signal component (e.g., cos(θ(t))) and the quadrature (Q) signal component (e.g., sin(θ(t))) to shift the phase of the I/Q signals  45  (e.g., signals cos(θ(t)), sin(θ(t))) by the envelope phase portion A p (t). The respective signals may be then respectively passed through the DACs  50  and  52 , the LPFs  56  and  58 , and the mixers  60  and  62  before being recombined and passed to the PA  70 .
 
     Similarly, when the dynamic EER polar transmitter  72  operates an EER polar transmitter, the time-domain representation of the envelope amplitude portion A a (t), which may be a constant amplitude envelope signal, may be restored to the envelope of the carrier signal and/or RF signal at the input of the PA  70 . That is, the dynamic EER polar transmitter  72  may operate as a traditional EER polar transmitter, in which the envelope amplitude portion A a (t) may be passed through the DAC  48  and the LPF  54  to the PA  70  to modulate the supply voltage of the amplifier  70 . In this way, the dynamic EER polar transmitter  72  may constantly transition between operating as an I/Q transmitter and an EER polar transmitter to increase and maximize the power efficiency of the dynamic EER polar transmitter  72 , and, by extension, decrease the power consumption of the electronic device  10 . Furthermore, as previously discussed, the alignment between amplitude and phase path sensitivity and power amplifier input and output leakage may also be improved utilizing presently disclosed techniques. 
     Turning now to  FIG. 9 , a waveform plot  78  illustrating the aforementioned amplitude envelope splitting and dynamic switching techniques as discussed above with respect to  FIG. 8  is presented. As depicted, the waveform plot  78  may include respective frequency-domain (e.g., digital domain) representations of an envelope amplitude signal  80  (e.g., “A”), an envelope amplitude portion signal  82  (e.g., “A a ”), and an envelope phase portion signal  84  (e.g., “A p ”). In certain embodiments, as further illustrated by  FIG. 9 , the dynamic envelop splitter  74  may track or analyze the envelope (e.g., the bandwidth of the envelope) of the signals  80 ,  82 , and  84 . As illustrated, during a period  86 , the envelope phase portion signal  84  (e.g., “A p ”) may be at an amplitude value of less than approximately 1V or other amplitude threshold value, and may correspond to a period at which the dynamic EER polar transmitter  72  may operate an EER polar transmitter. 
     However, as further illustrated by the waveform plot  78 , as the envelope amplitude signal  80  (e.g., “A”) and the envelope phase portion signal  84  (e.g., “A p ”) approaches, for example, the zero crossing (e.g., the origin or the zero value), the very wide frequency band (e.g., infinite frequency band) nature and nonlinear quality of the envelope phase portion signal  84  (e.g., “A p ”) causes the envelope amplitude signal  80  (e.g., “A”) and the envelope phase portion signal  84  (e.g., “A p ”) to experience the significant decreases in amplitude as illustrated during the period  88 . Therefore, during the period  88 , the dynamic EER polar transmitter  72  may transition from operating as an EER polar transmitter to operating as an I/Q transmitter in the performance of, for example, the modulation of the I/Q signal  45  as discussed above with respect to  FIG. 8 . This may also correspond to a time in which the envelope amplitude portion A a  is equal to or greater than approximately 1V or other amplitude threshold value as further illustrated. 
     In some embodiments, as further depicted by the waveform plot  78 , the dynamic EER polar transmitter  72  may continuously and/or concurrently transition between operating as an EER polar transmitter and operating as an I/Q transmitter. For example, during a period  89  in which the envelope amplitude signal  80  (e.g., “A”) and the envelope phase portion signal  84  (e.g., “A p ”) may momentarily increase to the amplitude threshold value (e.g., approximately 1V or just less than approximately 1V), the dynamic EER polar transmitter  72  may transition back to operating as an EER polar transmitter. Then, after the period  89 , the dynamic EER polar transmitter  72  may transition again to operating as I/Q transmitter. Indeed, in one or more embodiments, the dynamic EER polar transmitter  72  may operate, in combination, as an EER polar transmitter and an I/Q transmitter. 
     As further illustrated by the waveform plot  78 , once the envelope amplitude signal  80  (e.g., “A”) and the envelope phase portion signal  84  (e.g., “A p ”) passes the zero crossing (e.g., recovers from the dip in amplitude), which corresponds to a period  90 , the envelope phase portion signal  84  (e.g., “A p ”) may return to an amplitude threshold value (e.g., approximately 1V or just less than approximately 1V), and thus the dynamic EER polar transmitter  72  may transition from operating as an I/Q transmitter back to operating as an EER polar transmitter. In this way, the dynamic EER polar transmitter  72  may ensure that the power efficiency of the dynamic EER polar transmitter  72 , and, by extension, the power consumption of the electronic device  10  is maximized. This may further provide power efficiency and processing advantages when modulating and/or processing Bluetooth® EDR3 signals that may be unachievable using lesser advanced EER transmitters or even hybrid-EER transmitters. Still further, the present techniques may significantly improve the alignment between amplitude and phase path sensitivity and power amplifier input and output leakage. 
     Turning now to  FIG. 10 , a flow diagram is presented, illustrating an embodiment of a process  92  useful in increasing power efficiency in I/Q and polar transmitters by dynamically switching between operating as envelope elimination and restoration (EER) polar transmitter and an in-phase/quadrature (I/Q) transmitter using, for example, one or more processors that may be included within the dynamic EER polar transmitter  72  and/or the processor(s)  12  depicted in  FIGS. 1 and 8 . The process  92  may include code or instructions stored in a non-transitory machine-readable medium (e.g., the memory  14 ) and executed, for example, by the one or more processor(s)  12  and/or dynamic EER polar transmitter  72 . The process  92  may begin with the transmitter  44  receiving (block  94 ) a Cartesian representation of a data signal. For example, the dynamic EER polar transmitter  72  may receive a Cartesian coordinate represented signal  45 , which may include, for example, data symbols or constellations of data symbols encoded according to orthogonal I/Q vectors. 
     The process  92  may continue with the dynamic EER polar transmitter  72  generating (block  96 ) an amplitude envelope signal based on the Cartesian representation of the data signal. For example, as previously discussed above with respect to  FIG. 7 , the modulator  46  of the transmitter  72  may generate a constant time-domain amplitude envelope signal A(t) (e.g., which may be expressed as: √{square root over (I 2 +Q 2 )} or √{square root over (I(t) 2 +Q(t) 2 )}). The process  92  may then continue with the dynamic EER polar transmitter  72  decomposing or splitting (block  98 ) the amplitude envelope signal into an envelope amplitude portion or subcomponent and an envelope phase portion or subcomponent. For example, as noted above, the dynamic EER polar transmitter  72  may include a dynamic envelop splitter  74  that may be used to split the amplitude envelope signal A(t) into an envelope amplitude portion A a (t) and an envelope phase portion A p (t).) 
     The process  92  may then continue with the dynamic EER polar transmitter  72  determining (decision  99 ) whether the amplitude phase portion is less than an amplitude threshold value. If the amplitude phase portion is not less than the amplitude threshold value, the process  92  may then continue with the dynamic EER polar transmitter  72  performing (block  100 ) an EER modulation of the data signal. For example, as discussed above with respect to  FIGS. 8 and 9 , when the envelope phase portion A p  is equal to an amplitude threshold value (e.g., approximately 1V or just less than approximately 1V), the dynamic EER polar transmitter  72  may operate as an EER polar transmitter. On the other hand, if the amplitude phase portion is less than the amplitude threshold value, the process  92  may then continue with the dynamic EER polar transmitter  72  performing (block  102 ) I/Q modulation of the data signal. For example, whenever the envelope phase portion A p  decreases below an amplitude threshold value (e.g., amplitude value of approximately 1V or just less than approximately 1V), the dynamic EER polar transmitter  72  may transition from operating as an EER polar transmitter to operating as an I/Q transmitter. This may also correspond to a time in which the envelope amplitude portion A a  is equal to or greater than the amplitude threshold value. 
     The process  92  may then conclude with the dynamic EER polar transmitter  72  dynamically (block  104 ) switching between performing EER polar modulation and I/Q modulation based on the envelop amplitude portion and/or the envelope phase portion of the amplitude envelope signal. Specifically, as previously noted, the dynamic EER polar transmitter  72  may constantly transition between operating as an EER polar transmitter and an I/Q transmitter as a function of the envelope amplitude portion A a (t) and/or the envelope phase portion A p (t) of the amplitude envelope A(t). In this way, by constantly transitioning or switching between operating as an EER polar transmitter and an I/Q transmitter, the dynamic EER polar transmitter  72  may increase and maximize the power efficiency of the dynamic EER polar transmitter  72 , and, by extension, decrease the power consumption of the electronic device  10 . 
       FIG. 11  depicts a plot  114 , which illustrates the performance of an amplitude plot  106  and a phase plot  108  including amplitude and phase signals  110  and  114  generated without using the presently disclosed amplitude envelope splitting and dynamic switching techniques compared against amplitude and phase signals  112  and  116  generated using the presently disclosed amplitude envelope splitting and dynamic switching techniques. Specifically, the envelope amplitude signals  110  and  112  and the envelope phase signals  114  and  116  are plotted as functions of power spectrum magnitude (dBc) versus frequency. As illustrated by the plot  106 , the power spectrum magnitude of the amplitude signal  112  generated via the presently disclosed techniques decreases at a markedly faster rate than the amplitude signal  110 , and thus is much more linear as compared to the amplitude signal  110 . Similarly, the phase signal  116  generated via the presently disclosed techniques is significantly more linear than the phase signal  114  as each of the phase signals  114  and  116  approaches the zero crossing (e.g., zero value). Thus, the plots  106  and  108  illustrate the increased power efficiency when using the presently disclosed amplitude envelope splitting and dynamic switching techniques. 
     The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure.

Metadata:
Filing Date: 20150121
Publication Date: 20170912
Grant Date: 20170912
Priority Date: 20150121
Inventors: WOLBERG DAN
BLONSKEY OFER
Assignee: APPLE INC
CPC Classifications: [{"code": "H04L27/3405", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/3472", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L27/361", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/0287", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y02B60/50", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L27/3405", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04L27/3472", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L27/361", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y02D30/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04B2001/045", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04W52/0287", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04L27/3472", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L27/3405", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W52/0287", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y02D30/70", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04L27/361", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/04", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 56466335