text:
A radio frequency (RF) amplification system or transmitter includes one or more power amplifiers and a controller that is configured to adjust amplitudes and phases of RF input signals of the one or more power amplifiers and supply voltages applied to the one or more power amplifiers. The system may include a single digital-to-RF modulator and a power divider to drive multiple power amplifiers. A power combiner may also be provided to combine outputs of the power amplifiers. In at least one implementation, amplitude adjustment of the RF input signals of the one or more power amplifiers may be used to provide transmit power control and/or power backoff.
This application is a continuation of U.S. application Ser. No. 14/920,031, filed Oct. 22, 2015, a continuation-in-part of U.S. application Ser. No. 14/666,965, filed Mar. 24, 2015, now U.S. Pat. No. 9,209,758, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 62/185,803 filed Jun. 29, 2015 and which is a continuation of U.S. application Ser. No. 14/338,671, filed Jul. 23, 2014, now U.S. Pat. No. 9,020,453, which is a continuation of U.S. application Ser. No. 13/663,878, filed Oct. 30, 2012, now U.S. Pat. No. 9,166,536 and U.S. application Ser. No. 13/663,887, filed Oct. 30, 2012, now U.S. Pat. No. 8,824,978, all of which applications are hereby incorporated by reference herein in their entireties.
As is known in the art, a radio frequency (RF) transmitter is a device that produces RF signals. RF transmitters may be included, for example, as part of a radio communication system that uses electromagnetic waves (radio waves) to transport information over a distance.
As is also known, a trade-off must generally be made in RF communications transmitters between energy efficiency and linearity. Over the decades of development of the RF transmitter and corresponding RF amplifiers, it has generally been true that one could obtain either high efficiency or high linearity, but not both. It would, therefore, be desirable to provide systems and techniques that allow a user to amplify RF signals and/or transmit data carrying RF signals with both high efficiency and high linearity.
U.S. Pat. No. 8,824,978, which is herein incorporated by reference in its entirety, describes a transmitter amplifier architecture (referred to herein as the “Asymmetric Multilevel Backoff Amplifier” or “AMBO amplifier”) that has provides high efficiency operation at wide radio-frequency (RF) bandwidth with high linearity, efficient operation under power backoff, in addition to other advantages.
An AMBO amplifier may have plurality of RF power amplifiers (PAs) whose RF outputs are power combined to supply a system RF output, and whose PA drain bias voltages may be dynamically selected using voltage control units.
In known AMBO amplifiers, one way to drive the RF inputs of the PAs is for a controller to synthesize a digital command (e.g., an I/Q signal pair) for each PA. The digital commands are converted, through the use of two or more digital-to-RF modulators, into RF input signals for the PAs. By coordinating the switching of the PA drain bias voltages and the RF input commands to the PAs, an RF output can be generated that accurately reflects a desired digital I/Q input while preserving high efficiency and linearity at high bandwidth and across a wide range of power levels.
This implementation of AMBO with multiple digital-to-RF conversion paths is referred to herein as “dual-digital” AMBO.
Systems and techniques are described for amplifying and subsequently transmitting radio frequency (RF) signals with both high efficiency and high linearity.
In one embodiment, a digital-to-RF modulator provides an RF signal to an RF splitter configured to split the RF signal into a plurality of RF signals which are coupled to RF inputs of a like plurality of RF amplifiers. With this particular arrangement, digital control may be maintained over the amplitudes and the phases of RF input signals applied to one or more power amplifiers (PAs). Digital control may also be maintained over the supply voltages applied to the one or more PAs. In some embodiments, non-linear power amplifiers may be used to achieve high power efficiency within an RF transmitter. Digital control techniques may be used to achieve linearity and to further enhance efficiency. In at least one implementation, the amplitudes of one or more RF input signals of the one or more power amplifiers may be controlled to achieve backoff in the power amplifier to generate a desired output power level.
It is appreciated herein that dual-digital AMBO imposes certain limitations on system design and operation. First, requiring multiple digital-to-RF modulators (and associated digital-to-analog converters and I/Q modulators) can be expensive, representing a cost disadvantage as compared to systems utilizing only a single digital-to-RF path. Second, control and linearization considerations become much more complicated as compared to a system with a single digital-to-RF path. This includes computational costs (e.g., component cost and power dissipation) and challenges in realizing linearization (e.g., with digital predistortion), maintaining time alignment among the multiple paths, implementing signal correction such as “pulse cancellation”, etc. Moreover, these challenges become more pronounced as the number of PAs increases and/or at higher bandwidth operation, owing to the difficulty of providing all of the necessary computations and commands to the multiple digital paths and the multiple following RF paths.
According to one aspect of the disclosure, an RF amplification system comprises a digital-to-RF modulator to generate a modulated RF signal based on input information indicative of amplitude values and phase values; a plurality of RF amplifiers; an RF power divider to split the modulated RF signal into a plurality of RF input signals for the plurality of RF amplifiers; at least one voltage control unit to provide variable supply voltages to the plurality of RF amplifiers in response to at least one control signal; and a controller to receive input data and to provide the input information to the digital-to-RF modulator and the at least one control signal to the at least one voltage control unit based, at least in part, upon the received input data.
According to one aspect of the disclosure, an RF amplification system comprises a digital-to-RF modulator having a digital input port and an RF output port; a plurality of RF amplifiers, each of the RF amplifiers having an RF input port and an RF output port; an RF power divider having an RF input port coupled to the RF output port of the digital-to-RF modulator and having a like plurality of RF output ports with each of the RF output ports coupled to an RF input port of a respective one of the plurality of RF amplifiers; at least one voltage control unit to provide variable supply voltages to the first and second RF amplifiers in response to at least one control signal; and a controller to receive input data and to provide the input information to the digital-to-RF modulator and the at least one control signal to the at least one voltage control unit based, at least in part, upon the received input data.
In various embodiments, an RF amplification system further comprises an RF power combiner to combine amplified RF signals received from the plurality of RF amplifiers into a combined signal. In some embodiments, the RF power divider is configured to split the modulated RF signal into a plurality of RF signals having relative phases delays and wherein the RF power combiner is configured to match the relative phase delays such that the amplified RF signals are combined in phase.
The RF power divider may include a Wilkinson divider, a transmission-line splitter, a lumped-element splitting network, or a hybrid coupler. Similarly, the RF power combiner may include a Wilkinson combiner, a hybrid combiner, a Chireix combiner, a non-isolating combiner, transmission lines, a lumped-element reactive combiner, or a Doherty combiner.
In certain embodiments, at least one RF power divider is configured to split the modulated RF signal into a first RF signal having a first power level and a second RF signal having a second power level. The first and second power levels may be selected based upon power ratings for a first and second one of the plurality of RF amplifiers, respectively.
In some embodiments, at least one voltage control unit is configured to provide variable supply voltages selected from a plurality of discrete voltage levels. The at least one voltage control unit may be configured to generate the discrete voltage levels using a single-input, multiple-output power converter. In certain embodiments, the single-input, multiple-output power converter is provided as a switched-capacitor converter, a resonant switched-capacitor converter, or a single-inductor multiple-output converter. In some embodiments, at least one voltage control unit comprises transition shaping filters.
In several embodiments, an RF amplification system comprises a plurality of voltage control units to provide variable supply voltages to respective ones of the plurality of RF amplifiers.
FIG. 4 is a block diagram showing an RF amplification system having a multiple digital-to-RF signal paths, each of which includes a power divider having a plurality of power dividers.
The drawings are not necessarily to scale, or inclusive of all elements of a system, emphasis instead generally being placed upon illustrating the concepts, structures, and techniques sought to be protected herein.
Referring to FIG. 1, a radio frequency (RF) amplification system 10 includes a digital controller 12, a digital-to-RF modulator 14, an RF power divider 16, first and second RF amplifiers 18, 20, first and second voltage control units 22, 24, and an RF power combiner 26. Since the illustrative amplification system 10 includes two RF amplifiers, the system may be referred to as a two-way RF amplification system. Furthermore, in embodiments in which the RF amplifiers are provided as power amplifiers (PAs) 18, 20, the system may be referred to as a two-way power amplification system. The RF power amplification system 10 may correspond to an RF transmitter coupled to one or more antennas 32 and/or other transducers (or a transmission line) to facilitate the transmission of RF signals to one or more remote entities (e.g., remote wireless entities).
In some embodiments, the system 10 further includes an energy recovery module 30 coupled to RF power combiner 26.
Controller 12 includes an input to receive or otherwise obtain a stream of digital data to be amplified by the system 10 (i.e., transmit data). The transmit data may be in any suitable format (e.g., a binary bit stream; I and Q data; etc.). Controller 12 may use this transmit data, among other things, to provide input information to the digital-to-RF modulator 14 and control signals to first and second voltage control units 22, 24 that, in the example shown, will result in the transmission of the transmit data from antenna 32. Controller 12 may include any type of circuit, component, or system that is capable of performing the corresponding functions and operations described herein.
In various embodiments, the controller 12 provides digital signals (e.g., I and Q data) to the digital-to-RF modulator 14. In some implementations, the input information provided to the digital-to-RF modulator 14 may be in a format other than I and Q. For example, amplitude and phase information may be delivered to the digital-to-RF modulator 14 by controller 12.
As will become apparent form the description below, the controller can use the input information delivered to the digital-to-RF modulator 14 (e.g., an amplitude value associated with I and Q) to control/adjust a power level output by the system 10 (e.g., a transmit power level). For example, controller 12 may provide a reduced amplitude value for the digital-to-RF modulator 14 when a lower transmit power level is desired.
In various embodiments, the controller 12 adjusts control signals VCont1, VCont2 provided to the voltage control units 22, 24 and/or the input information provided digital-to-RF modulator 14 dynamically (e.g., in real-time) based on the received transmit data. For example, the controller 12 may dynamically select commands for the voltage control units 22, 24 that result in a discrete drain bias level (i.e., a supply voltage level) for each of the first and second PAs 18, 20. The controller may use level selection techniques described in U.S. Pat. No. 8,824,978.
In some embodiments, controller 12 is configured to update the information delivered to digital-to-RF modulator 14 and/or the control signals delivered to first and second voltage control units 22, 24 on a sample-by-sample basis. In at least one implementation, controller 12 is configured to provide independent control to each of first and second voltage control units 22, 24 so that different supply voltages can be simultaneously applied to first and second PAs 18, 20.
As described below, the output of the single digital-to-RF modulator 14 is split by the RF power divider 16 (e.g., an RF divider network) to drive the RF inputs of the two PAs 18, 20. To achieve high linearity, the controller 12 may utilize linearization techniques, e.g., digital predistortion with training feedback from the RF output. Linearization techniques such as supply-selection-dependent digital predistortion (DPD) and training methods, pulse cancellation (injected via corrections of the data inputs into the single digital-to-RF modulator), etc., can all be used for performance improvement, as in a dual-digital path AMBO system.
The digital-to-RF modulator 14 includes any suitable type of circuits or components operable to receive input information from the controller 12 and to generate an analog RF signal that enables an accurate representation of the transmit data to be provided at the antenna 32. In certain embodiments, the digital-to-RF modulator 14 is capable of converting digital input information representative of time-varying amplitude and phase into an analog RF output signal having corresponding amplitude and phase characteristics. The RF output of the digital-to-RF modulator 14 may be coupled directly to the RF power divider 16, as shown, or there may be one or more stages of amplitude adjustment (e.g., amplification or attenuation), impedance matching, and/or phase adjustment circuitry coupled between the modulator 14 and the power divider 16.
The system 10 may use any suitable modulation and coding scheme (MCS) to represent the transmit data within the RF transmit signal. For example, the system 10 may use binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), quadrature amplitude modulation (e.g., QAM, 16 QAM, 64 QAM, 128 QAM, etc), orthogonal frequency division multiplexing (OFDM), Code Division Multiple Access and/or other ways or encoding information and may meet the needs of transmit systems suitable for single or multi-carrier LTE or GSM standards. Some of these result in transmit signals that have relatively high peak to average power ratios. As is well known, transmit signals having high peak to average power ratios typically require highly linear power amplification to provide an accurate representation of transmit data. In various embodiments described herein, transmission systems and techniques are described that are capable of providing efficient power amplification with sufficient linearity to support transmit signals having high peak to average power ratios.
In some embodiments, the RF power divider 16 may be realized with a Wilkinson divider, a divider based on a transmission-line splitter, a lumped-element splitting network, or a hybrid circuit such as a rat-race hybrid coupler or a branch-line hybrid coupler used as a divider.
In various embodiments, the power divider 16 is configured to provide a predetermined fixed impedance to the digital-to-RF converter 14 regardless of the loading provided by the PA inputs. Those skilled in the art will understand that this can be provided, for example, using a hybrid coupler as a divider loaded with the matching PA inputs, as in a balanced amplifier. In other embodiments, the power divider 16 does not preserve fixed input impedance as the loading impedances vary.
In some embodiments, the power divider 16 is configured to generate RF output signals that are substantially aligned in phase. However, in some applications it may be preferable to have the PA input signals not aligned in phase. Here, the relative delays (i.e., phase shifts) of the divider 16 output signals may be selected to match and/or compensate for phase shifts of the power combiner 26 such that the RF outputs of the PAs 18, 20 combine in phase in the combiner 26. As such, the net delays through the two RF paths to the output (e.g., to antenna 32) can be matched.
For example, if the phase of the power divider output coupled to the first PA 18 leads the phase of the power divider output signal coupled to the second PA 20 by 90 degrees, then the power combiner 26 may be configured such that the phase from the first input of the combiner (connected to the output of the first PA 18) to the RF output lags, by 90 degrees, the phase from the second input of the combiner (connected to the output of the second PA 20) to the RF output. Such phase-delay matching can be achieved, for example, using a 90 degree coupler (e.g., a branchline hybrid coupler) within both power divider 16 and within power combiner 26.
As another example, phase-delay matching can be achieved by matching a rat-race hybrid used as a divider 16 with a rat-race hybrid used as a combiner 26 to appropriately match phases of the two paths to the output. As yet another example, phase-delay matching can be achieved using suitable length transmission lines coupled in the signal paths between outputs of the power divider 16 and/or inputs of the power combiner 26.
In various embodiments, the RF power divider 16 is configured to split input power (i.e., power in the RF signal received from the digital-to-RF modulator 14) equally among the PAs 18, 20. This may be preferred, for example, when the PAs are identical or similarly rated (or “sized”). In other embodiments—e.g., where the PAs 18, 20 have different power ratings (or “sizes”)—the power divider 16 may be configured to deliver unequal RF power to the PAs. In such a system with asymmetrical power dividing and/or power amplification, the power combiner 26 may likewise be configured for asymmetrical power combining such that maximum combining efficiency is achieved with asymmetrical power inputs from the PAs.
It will also be noted that the RF inputs to the PAs 18, 20 can be designed to remain constant impedance, or can be designed to vary under drive or drain-bias-voltage level. These design choices can affect how power is split among the PAs under different operating conditions, and may also affect the loading on the digital-to-RF modulator 14. Such loading effects may be accounted for (e.g., by compensation circuits or techniques) to yield desired a desired result.
In some embodiments, the power divider 16 is provided on the same circuit board or substrate as the PAs 18, 20 and/or upon the same circuit board/substrate as the power combiner 26. In other embodiments, the power divider 16 is provided on a different circuit board or substrate.
In some embodiments, the RF power divider 16 may be provided as an isolating power splitter. In certain embodiments, isolating power splitter with energy recovery may be used, such as the systems described in U.S. Pat. No. 8,830,710, Sep. 9, 2014 (entitled “RF Energy Recovery System”) and U.S. Pat. No. 8,830,709 (entitled “Transmission-Line Resistance Compression Networks and Related Techniques). In some embodiments, the RF power splitter 16 may utilize a transformer splitter, a Wilkinson splitter, a rat-race hybrid used as a splitter, or another type of other combiner or hybrid coupler circuits for power splitting. Further, the RF power splitter 16 can be provided as a type of non-isolating splitter, including a Resistance Compression Network, a splitter based on transmission lines (e.g., two quarter-wave transmission lines connected at one end), a lumped-element reactive splitter, or a Doherty splitter.
In some embodiments, power divider or splitter 16 may be an isolating splitter having an isolation port. As is known, an isolating splitter will sometimes output energy at the isolation port due to, for example, mismatches, imbalances, and/or reflections in the circuitry coupled to the splitter. Typically, a resistive termination will be coupled to the isolation port of an isolating splitter to provide an impedance match for the port and to dissipate any energy output from the port. Thus, in some embodiments, an energy recovery module (not shown) may be coupled to the isolation port of an isolating splitter, rather than a conventional resistive termination, for use in recovering some or all of the energy that would otherwise have been dissipated. Recovering energy from the splitter 16 may be less important than for the power combiner 26 owing to the lower relative power level, but may nonetheless be of value in achieving high efficiency. The energy recovery module (not shown) may include circuitry for converting the recovered energy into a useful form. For example, the recovered energy may be converted to a form that can be used to charge a battery. Alternatively, the recovered energy may be converted to a form that may be used to energize other circuitry within system 10.
First and second PAs 18, 20 may be provided as any type of power amplifier capable of amplifying an RF signal (e.g., a signal output from power divider 16). In some implementations, first and second PAs 18, 20 may be non-linear amplifiers (and, in some cases, highly non-linear amplifiers) to improve the efficiency of operation of the amplification system 10. First and second PAs 18, 20 may use the same amplifier design or different amplifier designs.
In some embodiments, the PAs 18, 20 have an input coupled to a respective output of the RF power divider 16, a drain bias input coupled to a respective one of the voltage control units 22, 24, and an output coupled to a respective input of the power combiner 26.
The PAs 18, 20 may have one or more stages of RF power amplification. As with other AMBO systems (e.g., systems described in U.S. Pat. No. 8,824,978), many types of PAs may be employed, including all the major classes (A, AB, B, C, D, E, F, inverse F, J, etc.) as well amplifiers containing multiple sub-amplifiers (e.g., Doherty Amplifiers, and Balanced Amplifiers). In some embodiments, the PAs 18, 20 are provided as RF-input outphasing amplifiers, such as those described in U.S. patent application Ser. No. 14/823,220 filed on Aug. 11, 2015 (entitled “RF-Input/RF-Output Outphasing Amplifier”).
First and second voltage control units 22, 24 may be provided as any type of circuit, component, or system operative for providing variable supply voltages to first and second PAs 18, 20, respectively, based on control signals received from controller 12. The voltage control units 22, 24 may include, for example, variable power supplies, discrete power supplies, batteries, multi-level power converters, and/or switching circuits that are capable of switching between preset voltage potentials.
In some embodiments, the voltage control units 22, 24 provide drain bias voltages to the PAs that may be may be dynamically selected to be different voltages. The voltage control units 22, 24 may each select a drain bias from two or more discrete levels, though other voltage control unit designs are possible, including those that provide a continuously adjustable output. As with other AMBO systems (such as the systems described in U.S. Pat. No. 8,824,978), the voltage control units 22, 24 may include transition-shaping filters. The discrete levels for the voltage control units may optionally be generated from a single power supply input using single-input, multi-output power converter such as a switched-capacitor converter, resonant switched-capacitor converter, single-inductor multiple-output converter, etc., or using multiple power supplies.
In some implementations, first and second voltage control units 22, 24 may be capable of providing one of a plurality of predetermined voltages to respective PAs 18, 20 in response to control signals from controller 12. Thus, a control signal VCONT1 may select a voltage value for PA 18 and a control signal VCONT2 may select a voltage value for PA 20. As with the input information applied to the digital-to-RF modulator 14, the supply voltage values applied to first and second PAs 18, 20 may change on a sample-by-sample basis in some embodiments.
Power combiner 26 may be provided from any type of device or structure operative for combining the output signals of first and second PAs 18, 20 to generate an RF transmit signal at an output thereof. The RF transmit signal may then be delivered to antenna 32 for transmission into a wireless channel. As will be appreciated, the RF transmit signal should include an accurate representation of the original transmit data (e.g., the data provided as input to controller 12).
In some embodiments, the RF power combiner 26 may be provided as an isolating power combiner. In certain embodiments, isolating power combiner with energy recovery may be used, such as the systems described in U.S. Pat. No. 8,830,710 (entitled “RF Energy Recovery System”) and U.S. Pat. No. 8,830,709 (entitled “Transmission-Line Resistance Compression Networks and Related Techniques). In some embodiments, the RF power combiner 26 may utilize a transformer combiner, a Wilkinson combiner, a rat-race hybrid used as a combiner, or another type of other combiner or hybrid coupler circuits for power combining. Further, the RF power combiner 26 can be provided as a type of non-isolating combiner, including a Chireix combiner, a combiner based on transmission lines (e.g., two quarter-wave transmission lines connected at one end), a lumped-element reactive combiner, or a Doherty combiner.
In some embodiments, power combiner 26 may be an isolating combiner having an isolation port. As is known, an isolating combiner will sometimes output energy at the isolation port due to, for example, mismatches, imbalances, and/or reflections in the circuitry coupled to the combiner. Typically, a resistive termination will be coupled to the isolation port of an isolating combiner to provide an impedance match for the port and to dissipate any energy output from the port. Thus, in some embodiments, an energy recovery module 30 may be coupled to the isolation port of an isolating combiner, rather than a conventional resistive termination, for use in recovering some or all of the energy that would otherwise have been dissipated. Energy recovery module 30 may include circuitry for converting the recovered energy into a useful form. For example, the recovered energy may be converted to a form that can be used to charge a battery. Alternatively, the recovered energy may be converted to a form that may be used to energize other circuitry within system 10.
In some embodiments, power combiner 26 may be implemented upon the same circuit board or substrate as the PAs 18, 20 and/or upon the same circuit board/substrate as the power divider 16. In other embodiments, power divider 26 is provided as a separate circuit element.
Although the illustrative RF amplification system 10 of FIG. 1 includes two PAs 18, 20 and two voltage control units 22, 24, it will be appreciated that the structures, concepts, and techniques described above can be generalized to systems having two or more PAs, one or more voltage control units, and one or more digital-to-RF signal paths.
It is appreciated that the generalized system architecture described above in conjunction with FIG. 1 provides a number of design benefits over existing RF amplification systems. For example, use of the RF split results in a system which only requires a single digital-to-RF modulator. System 10 thus provides a cost advantage over existing systems by eliminating the need for additional digital-to-RF modulators. It will be understood that the associated data converters and I/Q modulator that comprise a digital-to-RF modulator can be relatively expensive, especially in low-power systems. Moreover, the control complexity of the system can be substantially reduced as compared to a “dual digital” system, in that linearization only needs to manage one path for digital predistortion, pulse cancellation, etc., and one eliminates the need for calibration of time alignment of the multiple digital-to-RF paths. Owing to these complexity reductions and time alignment benefits, efficient performance to higher signal bandwidths can be achieved. Further, the reduced complexity means that the RF amplification system architecture described herein scales well to many-way AMBO systems, such as the systems shown in FIGS. 3 and 4 and described below in conjunction therewith.
Referring to FIG. 2, in which like elements of FIG. 1 are shown using like reference designators, an illustrative RF amplification system 40 includes a single voltage control unit 34 configured to provide variable voltages to multiple PAs (here two PAs 18, 20). Although one signal path is deprecated between the controller 12 and the voltage control unit 34 in FIG. 2, it should be appreciated that multiple control signals could be sent from the controller 12 to the voltage control unit 34. In some embodiments, a M-bit digital control signal is used.
Referring to FIG. 3, in which like elements of FIGS. 1 and 2 are shown using like reference designators, an RF amplification system can utilize an arbitrary number (N) of PAs and, thus, may be referred to as an N-way or many-way amplification system. An illustrative RF amplification system 50 includes N PAs 62 a, 62 b, 62 c, . . . , 62 n (generally denoted 62), each having an RF input coupled to a respective output of an N-way power divider 55, and an RF output coupled to a respective output of an N-way power combiner 70, as shown. Any of the PAs 62 may be the same as or similar to the PAs 18, 20 described above in conjunction with FIG. 1.
As shown, the system 50 may include an N-way voltage control unit 72, operative to receive one or more control signals from a controller 52 and to generate N variable supply voltages, each of which is applied to a respective one of the N PAs 62. In some embodiments, voltage control unit 72 is a digital control signal that encodes information to select levels for the N PAs 62. In other embodiments, an N-way RF amplification system 50 may include multiple voltage control units 72, each configured to apply a variable supply voltage to one or more of the PAs 62.
As with the embodiments of FIGS. 1 and 2, the illustrative system 50 may utilize a single digital-to-RF modulator 14. Thus, it will be appreciated that the N-way AMBO system architecture shown in FIG. 3 provides an economical way to achieve high power levels using relatively low-power PAs and voltage control units.
It should be appreciated that the power divider 55 can have any number of output ports so desired, including an odd number of output ports. For example, a 3-way Wilkinson divider comprising three lines and three resistive connections could be used.
Referring to FIG. 4, in which like elements of FIGS. 1-3 are shown using like reference designators, a N-way AMBO system can include a combination of digital-to-RF signal paths and RF-splits. In this example, a RF amplification system 80 includes N digital-to-RF paths (realized by N digital-to-RF modulators 84 a, 84 b, 84 n) each having M RF-splits (realized by respective M-way power dividers 86 a . . . 86 n) to drive a total of N×M PAs 88.
Digital-to-RF modulator 84 a, which may be representative of any other digital-to-RF modulator 84, has an input coupled to receive input information (e.g., I/Q data) from a controller 82, and an RF output coupled to a respective one of a plurality of power dividers 86 a, 86 b, . . . 86 n (generally denoted 86, with digital-to-RF modulator 84 being coupled to power divider 86 a in this example). The illustrative power divider 86 a has outputs coupled to respective RF inputs of M PAs 88 a, 88 b, . . . 88 m, as shown. The outputs of PAs 88 a, 88 b, . . . 88 m are combined with each other, and also with the outputs of all other PAs 88 to result in a system RF output signal for transmission via an antenna 32.
In this example, two levels of power combining are used. A first level corresponds to a plurality of M-way power combiners 90 a . . . 90 n, each of which may have inputs coupled to M respective of PAs and an output. The outputs of the first level power combiners 90 a . . . 90 n may be coupled as inputs to an N-way power combiner 92, which provides the second level of power combining. In other embodiments, the amplification system 80 could utilize a single level of power combining, such as a single power combiner having N×M inputs, or more than two levels of power combining. It should be appreciated that in some applications, it may be desirable or necessary to use only single level (or stage) or power combiners, for example by omit power combiners 90 a, 90 b, 90 c and having a power combiner 92 having N inputs.
The illustrative system 80 also includes a voltage control unit 94 configured to receive N×M control signals from the controller 82 and to apply N×M supply voltages to respective ones of the N×M PAs 88. As illustrated in FIG. 1, multiple voltage control units 94 can also be used.
It should be appreciated that any of the techniques, control and linearization methods, and design variants described in U.S. Pat. No. 8,824,978 in conjunction with so-called “dual digital” path AMBO systems can be applied to the concepts, systems, and structures sought to be protected herein.
Having described certain embodiments, which serve to illustrate various concepts, structures, and techniques sought to be protected herein, it will be apparent to those of ordinary skill in the art that other embodiments incorporating these concepts, structures, and techniques may be used. Elements of different embodiments described hereinabove may be combined to form other embodiments not specifically set forth above and, further, elements described in the context of a single embodiment may be provided separately or in any suitable sub-combination. Accordingly, it is submitted that scope of protection sought herein should not be limited to the described embodiments but rather should be limited only by the spirit and scope of the following claims.
a controller to receive input data and to provide the input information to said digital-to-RF modulator and the at least one control signal to said at least one voltage control unit based, at least in part, upon the received input data.
2. The RF amplification system of claim 1 further comprising an RF power combiner to combine amplified RF signals received from the plurality of RF amplifiers into a combined signal.
3. The RF amplification system of claim 2 wherein the RF power divider is configured to split the modulated RF signal into a plurality of RF signals having relative phases delays and wherein the RF power combiner is configured to match the relative phase delays such that the amplified RF signals are combined in phase.
4. The RF amplification system of claim 2 wherein the RF power divider comprises a Wilkinson divider, a transmission-line splitter, a lumped-element splitting network, or a hybrid coupler.
5. The amplification system of claim 2 wherein the RF power combiner comprises a Wilkinson combiner, a hybrid combiner, a Chireix combiner, a non-isolating combiner, transmission lines, a lumped-element reactive combiner, or a Doherty combiner.
6. The amplification system of claim 2 wherein the at least one RF power divider is configured to split the modulated RF signal into a first RF signal having a first power level and a second RF signal having a second power level.
7. The amplification system of claim 6 wherein the first and second power levels are selected based upon power ratings for a first and second one of the plurality of RF amplifiers, respectively.
8. The RF amplification system of claim 2 wherein the at least one voltage control unit is configured to provide variable supply voltages selected from a plurality of discrete voltage levels.
9. The RF amplification system of claim 8 wherein the at least one voltage control unit is configured to generate the discrete voltage levels using a single-input, multiple-output power converter.
10. The RF amplification system of claim 9 wherein the single-input, multiple-output power converter is provided as a switched-capacitor converter, a resonant switched-capacitor converter, or a single-inductor multiple-output converter.
11. The RF amplification system of claim 8 wherein the at least one voltage control unit comprises transition shaping filters.
12. The RF amplification system of claim 2 comprising a plurality of voltage control units to provide variable supply voltages to respective ones of the plurality of RF amplifiers.
a controller to receive input data and to provide the input information to the digital-to-RF modulator and the at least one control signal to the at least one voltage control unit based, at least in part, upon the received input data.
14. The RF amplification system of claim 13 further comprising an RF power combiner to combine amplified RF signals received from the plurality of RF amplifiers into a combined signal.
15. The RF amplification system of claim 14 wherein the RF power divider is configured to split the modulated RF signal into a plurality of RF signals having relative phases delays and wherein the RF power combiner is configured to match the relative phase delays such that the amplified RF signals are combined in phase.
16. The RF amplification system of claim 14 wherein the RF power divider comprises a Wilkinson divider, a transmission-line splitter, a lumped-element splitting network, or a hybrid coupler.
17. The amplification system of claim 14 wherein the RF power combiner comprises a Wilkinson combiner, a hybrid combiner, a Chireix combiner, a non-isolating combiner, transmission lines, a lumped-element reactive combiner, or a Doherty combiner.
18. The amplification system of claim 14 wherein the at least one RF power divider is configured to split the modulated RF signal into a first RF signal having a first power level and a second RF signal having a second power level.
19. The amplification system of claim 18 wherein the first and second power levels are selected based upon power ratings for a first and second one of the plurality of RF amplifiers, respectively.
20. The RF amplification system of claim 14 wherein the at least one voltage control unit is configured to provide variable supply voltages selected from a plurality of discrete voltage levels.
21. The RF amplification system of claim 20 wherein the at least one voltage control unit is configured to generate the discrete voltage levels using a single-input, multiple-output power converter.
22. The RF amplification system of claim 21 wherein the single-input, multiple-output power converter is provided as a switched-capacitor converter, a resonant switched-capacitor converter, or a single-inductor multiple-output converter.
23. The RF amplification system of claim 20 wherein the at least one voltage control unit comprises transition shaping filters.
24. The RF amplification system of claim 14 comprising a plurality of voltage control units to provide variable supply voltages to respective ones of the plurality of RF amplifiers.
Amendment to Office Action dated Apr. 7, 2011 (U.S. Appl. No. 12/680,048, filed Mar. 25, 2010).
Beltran, et al.; "HF Outphasing Transmitter Using Class-E Power Amplifiers;" Microwave Symposium Digest, IEEE; Jun. 2009; pp. 757-760.
Bifrane, et al.; "On the Linearity and Efficiency of Outphasing Microwave Amplifiers;" IEEE Transactions on Microwave Theory and Techniques; vol. 52; No. 7; Jul. 2004; pp. 1702-1708.
Chen, et al.; "A High Efficiency Outphasing Transmitter Structure for Wireless Communications;" Digital Signal Processing Workshop, IEEE; Jan. 2009, pp. 348-352.
Chireix; "High Power Outphasing Modulation;" Proceedings of the Institute of Radio Engineers; vol. 23; No. 11; Nov. 1935; pp. 1370-1392.
Communication pursuant to Article 94(3) EPC dated Jan. 5, 2017 for European Patent Application No. 13 851 838.6; 4 Pages.
Cox; "Linear Amplification with Nonlinear Components;" IEEE Transactions on Communications; Dec. 1974; pp. 1942-1945.
Cripps; "RF Power Amplifier for Wireless Communications, 2nd Ed.;" Chapter 14, Artech House, Boston, MA; Jan. 2006.
D. Diaz, et al., "Comparison of Two Different Cell Topologies for a Multilevel Power Supply to Achieve High Efficiency Envelope Amplifier", IEEE , 2009, pp. 25-30.
El-Hamamsy; "Design of High-Efficiency RF Class-D Power Amplifier;" IEEE Transactions on Power Electronics; vol. 9; No. 3; May 1994; pp. 297-308.
Eun, et al.; "A High Linearity Chireix Outphasing Power Amplifier Using Composite Right/Left-Handed Transmission Lines;" Proceedings of the 37th European Microwave Conference; Oct. 2007; pp. 1622-1625.
European Extended Search Report dated Jul. 4, 2016; for European Appl. No. 13858970.0; 7 pages.
European Extended Search Report dated Mar. 10, 2016 corresponding to European Application No. 3851200.9; 8 Pages.
European Extended Search Report dated May 17, 2016; for European Pat. App. No. 13851838.6, 8 pages.
Everitt, et al.; "Communication Engineering;" 3rd Edition, Chapter 11, pp. 403-450, New York: McGraw-Hill, 1956.
Frederick H. Raab, et al., "RF and Microwave Power Amplifier and Transmitter Technologies-Part 3", Sep. 2003, High Frequency Electronics, Summit Technical Media, LLC., pp. 34-48.
Frederick H. Raab, et al., "RF and Microwave Power Amplifier and Transmitter Technologies—Part 3", Sep. 2003, High Frequency Electronics, Summit Technical Media, LLC., pp. 34-48.
Gerhard, et al.; "Improved Design of Outphasing Power Amplifier Combiners;" 2009 German Microwave Conference; Mar. 2009; pp. 1-4.
Godoy et al.: "A 2.5-GHz asymmetric multilevel outphasing power amplifier in 65-nm CMOS"; Massachusetts Institute of Technology, IEEE 2011; pp. 57-60 (4 pages).
Godoy, et al.; "Outphasing Energy Recovery Amplifier With Resistance Compression for Improved Efficiency;" IEEE Transactions on Microwave Theory and Techniques; vol. 57; No. 12; Dec. 2009; pp. 2895-2906.
Hakala, et al., "A 2.14-GHz Chireix Outphasing Transmitter;" IEEE Transactions on Microwave Theory and Techniques; vol. 53; No. 6; Jun. 2005; pp. 2129-2138.
Hakala, et al.; Chireix Power Combining with Saturated Class-B Power Amplifiers; 12th GAAS Symposium; Oct. 2004, pp. 379-382.
Hamill; "Impedance Plan Analysis of Class DE Amplifier;" Electronics Letters; vol. 30; No. 23; Nov. 10, 1994; pp. 1905-1906.
Hamill; "Time Reversal Duality Between Linear Networks;" IEEE Transactions on Circuits and Systems-I: Fundamental Theory and Applications; vol. 43; No. 1; Jan. 1996; pp. 63-65.
Hamill; "Time Reversal Duality in Dc-Dc Converters;" Power Electronics Specialists Conference, IEEE; vol. 1; Jun. 1997; 7 pages.
Han, et al.; "Analysis and Design of High Efficiency Matching Networks;" IEEE Transactions on Power Electronics; vol. 21; No. 5, Sep. 2006; pp. 1484-1491.
Han, et al.; "Resistance Compression Networks for Radio-Frequency Power Conversion;" IEEE Transactions on Power Electronics; vol. 22; No. 1; Jan. 2007; pp. 41-53.
Heijden, et al.; "A 19W High-Efficiency Wide-Band CMOS-GaN Class-E Chireix RF Outphasing Power Amplifier" Microwave Symposium Digest (MMT), 2011 IEEE MTT-S International; Jun. 5-10, 2011; 4 pages.
Honjo; "A Simple Circuit Synthesis Method for Microwave Class-F Ultra-High-Efficiency Amplifiers with Reactance-Compensation Circuits;" Solid-State Electronics 44; Feb. 2000; pp. 1477-1482.
Hur, et al.; "A Muiti-Level and Multi-Band Class-D CMOS Power Amplifier for the LINC System in the Cognitive Radio Application;" IEEE Microwave and Wireless Components Letters; vol. 20; Issue 6; Jun. 2010; pp. 1-3.
Hur, et al.; "Highly Efficient and Linear Level Shifting Digital LINC Transmitter with a Phase Offset Cancellation;" Radio & Wireless Symposium; Jan. 2009; pp. 211-214.
Hur, et al.; "Highly Efficient Uneven Multi-Level LINC Transmitter;" Electronics Letters; Jul. 30, 2009; vol. 45; No. 16; 2 pages.
International Preliminary Report on Patentability of the ISA for PCT/US2009/063821 dated May 26, 2011.
International Preliminary Report on Patentability of the ISA for PCT/US2011/023613 dated Aug. 16, 2012.
Invitation to Pay Additional Fees in PCT/US2009/063821 dated Feb. 9, 2010.
Japanese Voluntary Amendment and Request for Examination (with English amended claims) filed Nov. 2, 2016; for Japanese Pat. App. 2015-544088; 17 pages.
Japanese Voluntary Amendment and Request for Examination (with English amended claims) filed Oct. 4, 2016; for Japanese Pat. App. 2015-539669; 19 pages.
Japanese Voluntary Amendment and Request for Examination (with English amended claims) filed Oct. 4, 2016; for Japanese Pat. App. 2015-539670; 19 pages.
Jinsung Choi, et al., "A ΔΣ-Digitized Polar RF Transmitter", IEEE Transactions on Microwave Theory and Techniques, vol. 55, No. 12, Dec. 2007, pp. 2679-2690.
Kai-Yuan Jheng, et. al., "Multilevel LINC System Design for Power Efficiency Enhancement", IEEE, 2007, pp. 31-34.
Kee, et al.; "The Class-E/F Family of ZVS Switching Amplifiers;" IEEE Transactions on Microwave Theory and Techniques; vol. 51; No. 6; Jun. 2003; pp. 1677-1690.
Kevin Tom, et al., "Load-Pull Analysis of Outphasing Class-E Power Amplifier", The 2nd International Conference on Wireless Broadband and Ultra Wideband Communications (AusWireless 2007), IEEE, 2007, pp. 1-4.
Kruass, et al.; Solid State Radio Engineering; Chapter 14, New York: Wiley, 1980.
Langridge, et al.; "A Power Re-Use Technique for improved Efficiency of Outphasing Microwave Power Amplifiers;" IEEE Transactions on Microwave Theory and Techniques; vol. 47; No. 8; Aug. 1999; pp. 1467-1470.
Lee; "Planar Microwave Engineering;" Chapter 20, pp. 630-687, New York: Cambridge University Press, 2004.
Lepine, et al.; "L-Band LDMOS Power Amplifiers Based on an Inverse Class-F Architecture;" IEEE Transactions on Microwave Theory and Techniques; vol. 53; No. 6; Jun. 2005; pp. 2007-2012.
M. Rodriguez, et al., "Multilevel Converter for Enevlope Tracking in RF Power Amplifiers", IEEE, 2009, pp. 503-510.
Ni, et al.; "A New Impedance Match Method in Serial Chireix Combiner;" 2008 Asia-Pacific Microwave Conference; Dec. 2008; pp. 1-4.
Non-Final Office Action dated May 18, 2016; for U.S. Appl. No. 14/934,760, 31 pages.
Non-Final Rejection dated Aug. 26, 2016; for U.S. Appl. No. 14/968,045; 30 pages.
Notice of Allowance dated Aug. 13, 2015 for U.S. Appl. No. 13/663,878; 13 Pages.
Notice of Allowance dated Aug. 24, 2016; for U.S. Appl. No. 14/920,031; 29 pages.
Notice of Allowance dated Aug. 25, 2015 corresponding to U.S. Appl. No. 14/666,965; 16 Pages.
Notice of Allowance dated Aug. 3, 2015 for U.S. Appl. No. 14/064,572; 13 Pages.
Notice of Allowance dated Dec. 1, 2016 for European Patent Application No. 13/851,200.9; 60 Pages.
Notice of Allowance dated Jul. 14, 2014 for U.S. Appl. No. 13/833,050, filed Mar. 15, 2013; 23 Pages.
Notice of Allowance dated Jul. 29, 2015 for U.S. Appl. No. 13/955,952; 11 Pages.
Notice of Allowance dated Jul. 7, 2016; for U.S. Appl. No. 14/934,760; 9 pages.
Notice of Allowance for U.S. Appl. No. 13/663,887, filed Oct. 30, 2012.
Office Action dated Apr. 24, 2015 for U.S. Appl. No. 14/064,572; 10 Pages.
Office Action dated Feb. 22, 2017 from U.S. Appl. No. 15/287,068; 43 Pages.
Office Action dated Feb. 23, 2015; for U.S. Appl. No. 14/064,572, filed Oct. 28, 2013; 29 Pages.
Office Action dated Feb. 24, 2017 from U.S. Appl. No. 14/968,045; 15 Pages.
Office Action dated Jan. 26, 2015 for U.S. Appl. No. 13/955,952, filed Jul. 31, 2013; 30 Pages.
Office Action dated Jul. 8, 2015 for U.S. Appl. No. 13/955,952; 13 Pages.
Office Action dated Jun. 2, 2015 for U.S. Appl. No. 13/663,878; 18 Pages.
Office Action dated Mar. 2, 2017 from U.S. Appl. No. 14/837,616; 13 Pages.
Office Action dated May 21, 2015 for U.S. Appl. No. 14/666,965; 15 Pages.
Office Action dated May 23, 2014 from U.S. Appl. No. 13/663,878, filed Oct. 30, 2012; 20 Pages.
Office Action dated May 7, 2015 for U.S. Appl. No. 13/663,878, filed Oct. 30, 2012; 23 Pages.
Office Action dated Oct. 29, 2014 for U.S. Appl. No. 13/633,878, filed Oct. 30, 2012; 15 Pages.
PCT International Preliminary Report on Patentability dated Jun. 2, 2015 for Intl. Application No. PCT/US2013/070027; 12 Pages.
PCT International Preliminary Report on Patentability dated May 14, 2013 for Intl. Application No. PCT/US2013/06553; 13 Pages.
PCT International Preliminary Report on Patentability dated May 14, 2015 for Intl. Application No. PCT/US2013/06552; 13 Pages.
PCT Search Report of the ISA dated Apr. 13, 2010.
PCT Search Report of the ISA for PCT/US2011/023613 dated May 30, 2011.
PCT Search Report of the ISA for PCT/US2013/065552 dated Mar. 20, 2014.
PCT Search Report of the ISA for PCT/US2013/065553 dated Mar. 20, 2014.
PCT Search Report of the ISA for PCT/US2013/70027 dated Apr. 22, 2014.
PCT Written Opinion of the ISA dated Apr. 13, 2010.
PCT Written Opinion of the ISA for PCT/US2011/023613 dated May 30, 2011.
PCT Written Opinion of the ISA for PCT/US2013/70027 dated Apr. 22, 2014.
Perreeult; A New Power Combining and Outphasing Modulation System for High-Efficiency Power Amplification; Circuits and Systems (MWSCAS), 53rd IEEE, International Midwest Symposium; Aug. 2010; pp. 1-14.
Petri Eloranta, et al., "A multimode Transmitter in 0.13 μ m CMOS Using Direct-Digital RF Modulator", IEEE Journal of Solid-State Circuits, vol. 42, No. 12, Dec. 2007, pp. 2774-2784.
Qureshi, et al.; "A 90-W Peak Power GaN Outphasing Amplifier with Optimun Input Signal Conditioning;" IEEE Transactions on Microwave Theory and Techniques; vol. 57; No. 8; Aug. 2009; pp. 1925-1935.
Raab, et al.; "RF and Microwave Power Amplifier and Transmitter Technologies-Part 3;" High Frequency Electronics; Sep. 2003; pp. 34-48.
Raab, et al.; "RF and Microwave Power Amplifier and Transmitter Technologies—Part 3;" High Frequency Electronics; Sep. 2003; pp. 34-48.
Raab; "Average Efficiency of Class-G Power Amplifiers;" IEEE Transactions on Consumer Electronics; vol. CE-32; No. 2; May 1986; pp. 145-150.
Raab; "Class-F Power Amplifiers with Maximally Rat Waveforms;" IEEE Transactions on Microwave Theory and Techniques; vol. 45; No. 11; Nov. 1997; pp. 2007-2012.
Raab; "Efficiency of Outphasing RF Power-Amplifier Systems;" IEEE Transactions on Communications; vol. Com-33; No. 10; Oct. 1985; pp. 1094-1099.
Response filed Dec. 30, 2014 of Office Action dated Oct. 29, 2014 for U.S. Appl. No. 13/663,878, filed Oct. 30, 2012; 20 Pages.
Response filed Mar. 10, 2015 of Office Action dated Feb. 23, 2015 for U.S. Appl. No. 14/064,572, filed Oct. 28, 2013; 3 Pages.
Response filed on Dec. 6, 2016 to Non-Final Office Action dated Sep. 15, 2016; for U.S. Appl. No. 14/837,616; 3 pages.
Response filed on Jun. 3, 2016 to Non-Final Office Action dated May 18, 2016; for U.S. Appl. No. 14/934,760; 10 pages.
Response to Communication dated Dec. 5, 2016 with amended claims for European Patent Application No. 13/851,838.6; 7 Pages.
Response to Final Office Action dated Jun. 2, 2015 for U.S. Appl. No. 13/663,878; Response filed on Jul. 21, 2015; 13 Pages.
Response to Office Action dated Apr. 24, 2015 for U.S. Appl. No. 14/064,572; Response filed on Jul. 17, 2015; 9 Pages.
Response to Office Action dated Feb. 22, 2017 from U.S. Appl. No. 15/287,068, filed May 16, 2017; 8 Pages.
Response to Office Action dated Feb. 23, 2015 for U.S. Appl. No. 14/064,572; Response filed on Mar. 10, 2015; 3 Pages.
Response to Office Action dated Feb. 24, 2017 from U.S. Appl. No. 14/968,045, filed May 12, 2017; 9 Pages.
Response to Office Action dated Mar. 2, 2017 from U.S. Appl. No. 14/837,616, filed Jun. 1, 2017; 9 Pages.
Response to Office Action dated May 21, 2015 corresponding to U.S. Appl. No. 14/666,965; Response filed on Jul. 23, 2015; 12 Pages.
Response to Office Action dated May 23, 2014 as filed on Jul. 31, 2014 from U.S. Appl. No. 13/663,878, filed Oct. 30, 2012; 7 Pages.
Response to Office Acton dated Jan. 26, 2015 for U.S. Appl. No. 13/955,952; Response filed on May 26, 2015; 11 Pages.
Response to Ruie 161 communication dated Jun. 28, 2011; Jan. 9, 2012.
Response to the Jul. 21, 2016 communication pursuant to Rules 72(2) and 70a(e) EPC from European Application No. 13858970.0 as filed on Jan. 31, 2017; 5 Pages.
Rivas, et al.; "A High-Frequency Resonant Inverter Topology with Low-Voltage Stress;" IEEE Transactions on Power Electronics; vol. 23; No. 4; Jul. 2008; pp. 1759-1771.
Shirvani, et al.; "A CMOS RF Power Amplifier With Parallel Amplification for Efficient Power Control;" IEEE Journal of Solid-State Circuits; vol. 37; No. 6; Jun. 2002; pp. 684-693.
Sokal, et al.; "Class E-A New Class of High-Efficiency Tuned Single-Ended Switching Power Amplifiers;" IEEE Journal of Solid-State Circuits; vol. SC-10; No. 3; Jun. 1975; pp. 168-176.
Sokal; "Class-E RF Power Amplifiers;" QEX; Jan./Feb. 2001; pp. 9-20.
Sungwon Chung, et al., "Asymmetric Multilevel Outphasing Architecture for Multi-Standard Transmitters", 2009 IEEE Radio Frequency Integrated Circuits Symposium, pp. 237-240.
Supplemental Response to Office Action dated May 21, 2015 corresponding to U.S. Appl. No. 14/666,965; Supplemental Response filed on Aug. 10, 2015; 9 Pages.
Surya Musunuri, et al., "Improvement of Light-Load Efficiency Using Width-Switching Scheme for CMOS Transistors", IEEE Power Electronics Letters, vol. 3, No. 3, Sep. 2005, pp. 105-110.
U.S. Appl. No. 12/615,696, filed Nov. 10, 2009.
U.S. Appl. No. 13/020,568, filed Feb. 3, 2011.
U.S. Appl. No. 13/106,195, filed May 12, 2011.
U.S. Appl. No. 13/423,909, filed Mar. 19, 2012.
U.S. Appl. No. 13/423,909, flied Mar. 19, 2012.
U.S. Appl. No. 14/758,033, filed Jun. 26, 2015, Perreault et al.
Vasic, et al.; "Multilevel Power Supply for High Efficiency RF Amplifiers;" 2009 IEEE Applied Power Electronics Conference; pp. 1233-1238; Feb. 2009.
Written Opinion of the ISA for PCT/US2013/065552 dated Mar. 20, 2014.
Written Opinion of the ISA for PCT/US2013/065553 dated Mar. 20, 2014.
Xu, et al.; "A 28.1dBm class-D outphasing power amplifier in 45nm LP digital CMOS;" Symposium on VLSI Circuits Digest of Technical Papers; Jun. 16, 2009; pp. 206-207.
Yan, et al.; "A High Efficiency 780 MHz GaN Envelope Tracking Power Amplifier," 2012 Compound Semiconductor Integrated Circuits Syumposium; Oct. 2012; pp. 1-4.
Yao, et al.; "Power Amplifier Selectlon for LINC Applications;" IEEE Transactions on Circuits and Systems-II: Express Briefs; vol. 53; No. 8; Aug. 2006; pp. 763-767.
Yousefzadeh, et al.; "Three-Level Buck Converter for Envelope Tracking Applications;" IEEE Transactions on Power Electronics; vol. 21; No. 2; Mar. 2006; pp. 849-552.
Yuan-Jyue Chen, et al., "Multilevel LINC System Design for Wireless Transmitters", IEEE, 2007, pp. 1-4.
Zhang, et al.; "Analysis of Power Recycling Techniques for RF and Microwave Outphasing Power Amplifiers;" IEEE Transactions on Circuits and Systems-II: Analog and Digital Signal Processing; vol. 49; No. 5; May 2002; pp. 312-320.
Zhou, et al.; "A Distributed Active Transformer Coupled Outphasing Power Combiner," Microwave Conference, IEEE; Dec. 7, 2009; pp. 2565-2568.
Zhou, et al.; "A Distributed Active Transformer Coupled Outphasing Power Combiner;" IEEE Microwave Conference; Dec. 2009; pp. 2565-2568.
Zhukov, et al.; "Push-pull switching oscillator without commutating losses," Poluprovodnikovye Pribory v. Tekhnike Elektrosvyazi, No. 15, Jan. 1975, 8 pages.

matches:
§119
Application No. 62
Application No. 13
Application No. 3851200
Application No. 13
Application No. 13
Application No. 13858970
v.


text:
Justia › US Law › US Case Law › US Supreme Court › Volume 290 › Miller v. Union Pacific R. Co.
Miller v. Union Pacific R. Co.
can plainly be seen for a distance of 2,000 feet, either fails to look, or takes a chance on beating the train over the crossing, is guilty of contributory negligence as matter of law; and, in an action for damages for his death, the trial court properly may take the case from the jury and dismiss the petition on the merits with prejudice. P. 290 U. S. 231.
2. The doctrine that the negligence of the driver of a vehicle is imputed to a passenger has been abandoned in England, rejected by the great weight of authority in this country, and distinctly repudiated by this Court. P. 290 U. S. 231.
3. Whether a right of recovery may be denied on the ground of contributory negligence in the case of a passenger or guest who suffers personal injury or death in a public or private conveyance over the movement of which he has no control depends upon his own failure to exercise a proper degree of care, and not upon that of the driver. This applies as well where the passenger is the wife of the driver as in other cases. P. 290 U. S. 232.
4. The rule in the federal courts is settled that the burden of proving contributory negligence rests upon the defendant. P. 290 U. S. 232.
5. Where contributory negligence is established by the plaintiff's own evidence, the defendant may have the benefit of it. P. 290 U. S. 232.
6. Where there is no evidence which speaks one way or the other with respect to contributory negligence of a decedent, the presumption is that there was no such negligence. P. 290 U. S. 233.
7. Where the evidence establishes that an accident to an automobile at a railroad crossing, killing both the driver and his passenger, was due to the concurrent negligence of the railroad in operating its train at an unusual and unlawful speed and without sounding whistle, and of the driver of the automobile in attempting to cross the track, and where there is no evidence of how the passenger acted in the emergency, the passenger cannot be held guilty of contributory negligence as a matter of law, nor can his death be attributed to the negligence of the driver alone as the sole proximate cause. P. 290 U. S. 233.
8. Where injury is caused by the concurring negligence of the defendant and a third person, the defendant is liable to the same extent as though it had been caused by his negligence alone. P. 290 U. S. 236.
Certiorari to review a judgment affirming a judgment dismissing on the merits with prejudice an action against the railroad company for deaths by wrongful act.
The case had been removed from a state court on the ground of diversity of citizenship.
In December, 1927, decedents, Marcus Andlauer and his wife, Ellanore Andlauer, while attempting to cross respondent's railroad track at a highway intersection within a few feet of the easterly boundary line of the city of St. Marys, Kansas, were killed as the result of a collision between a train of respondent and the automobile in which they were riding. The wife sat in the front seat with her husband, who was driving. The automobile had been driven westerly along a highway parallel to the railroad track to a point about 71 feet south of the railroad track, where it was turned into a road running northerly across the track, and driven thence without change of speed at the rate of 12 or 15 miles per hour until the accident. The day was clear. The crossing was a familiar one to decedents, and, from the point where the automobile was turned to a point beyond the crossing, trains from the east were in plain view for a distance of 2,000 feet. The train which caused the accident came from the east at a speed of from 50 to 60 miles an hour. There was evidence that the whistle was not sounded, that the train was about an hour late, that it usually slowed down in approaching the crossing to about 25 or 30 miles per hour, and that a city ordinance limited the speed of trains within the city to 20 miles per hour. The rear wheels of the automobile were on or very near the south rail of the track when the collision occurred.
The trial court took the case from the jury and dismissed the petition on the merits with prejudice, holding that both decedents were guilty of contributory negligence as matter of law. This judgment the Circuit Court of Appeals affirmed. 63 F.2d 574.
"that, if proper precautions were taken, they could not have failed to prove effectual, the court has no right to assume, especially in face of all the oral testimony, that such precautions were taken. . . . Judging from the common experience of men, there can be but one plausible solution of the problem how the collision occurred. He did not look, or, if he looked, he did not heed the warning, and took the chance of crossing the track before the train could reach him. In either case, he was clearly guilty of contributory negligence."
Authority for this view was found especially in Railroad Co. v. Houston, 95 U. S. 697, 95 U. S. 702.
abandoned in England (The Bernina, 12 Pro.Div. 58), was never generally accepted in this country. Followed by a few state decisions, it was rejected by the great weight of American authority, and, after full consideration, distinctly repudiated by this Court. Little v. Hackett, 116 U. S. 366. And see Union Pac. Ry. Co. v. Lapsley, 51 F. 174. Whether a passenger or guest in a public or private conveyance, having no control over its movement, may be denied a right of recovery for personal injury or death on the ground of contributory negligence depends upon his own failure to exercise a proper degree of care, and not upon that of the driver. This is true where the passenger is the wife of the driver as in other cases. Chicago, R.I. & P. Ry. Co. v. Fanning, 42 F.2d 799, 803. And, while the state decisions are not uniform on the subject, the federal rule is definitely settled that the burden of proving such contributory negligence rests, in all cases, upon the defendant, Railroad Co. v. Gladmon, 15 Wall. 401, 82 U. S. 406-407; Texas & Pacific Ry. Co. v. Volk, 151 U. S. 73, 151 U. S. 77-78; Central Vermont Ry. v. White, 238 U. S. 507, 238 U. S. 512, although, if such negligence be established by plaintiff's evidence, it hardly seems necessary to add, defendant may have the benefit of it, Washington & Georgetown R. Co. v. Harmon, 147 U. S. 571, 147 U. S. 580-581; Indianapolis & St.L. R. Co. v. Horst, 93 U. S. 291, 93 U. S. 298-299.
In the present case, as already appears, the burden was sustained as to the husband. It was not sustained as to the wife. As to her, there is an entire absence of evidence on the point. Whatever duty rested upon her under the circumstances, for aught that appears to the contrary, may have been fully discharged. It properly cannot be said from anything shown by the record before us that she did not maintain a careful lookout for the train, or that, if aware of its approach, she did not warn her husband or urge him to stop before entering upon the crossing.
Want of due care for her own safety must be proved; it cannot be presumed. The presumption is the other way. Texas & Pacific Ry. Co. v. Gentry, 163 U. S. 353, 163 U. S. 366; Baltimore & Potomac R. v. Landrigan, 191 U. S. 461, 191 U. S. 473-474; Atchison, T. & S.F. Ry. Co. v. Toops, 281 U. S. 351, 281 U. S. 356. If, as here, there be no evidence which speaks one way or the other with respect to contributory negligence of the person killed, it is presumed that there was no such negligence. Looney v. Metropolitan R. Co., 200 U. S. 480, 200 U. S. 488.
Here, the wife was not in control of the movement of the automobile. She could only note the danger, warn her husband, and urge him to stop. She may have done so, and he, misjudging the situation or taking the chance, have gone forward nevertheless. Or she may have seen the approaching train, observed that her husband was also aware of the fact, and, relying upon her knowledge of his habits and character, trusted him, with good reason, until it became too late to interfere, to do whatever was necessary to avoid the danger. The applicable rule is found in Southern Pac. Co. v. Wright, 248 F. 261, 264. That was a case where one Wright was riding in a motor truck with an experienced chauffeur as driver. A collision occurred between the truck and a train, which resulted in Wright's death. It did not appear whether Wright saw the train before it was seen by the chauffeur. The court said that he might have seen it and yet reasonably remained silent on the assumption that, the view being unobstructed, the chauffeur also saw it and was governing himself accordingly.
and disconcerted the driver, and an instant of indecision in such a case may be fatal. Here, with the truck a half a second sooner or the train a half a second later, the tragedy would not have happened. It must be borne in mind that there was no time to reflect or reason. If the train was running only 30 miles an hour -- the speed was probably greater -- it was only about 30 seconds from the time it came into view a quarter of a mile away until it crashed into the truck."
Accordingly, it was held that the question of Wright's contributory negligence was not one of law, but one of fact for the jury.
"Believing the car was about to stop, he may have thought that warning would be needless, and, discovering too late that the car was going on, he may have thought that interference would be dangerous. These and like possibilities were to be estimate by the triers of the facts. They make it impossible to deal with the issue as a question for the court."
Bradley v. Missouri Pac. R. Co., 288 F. 484, is cited by respondent to the contrary, but, to the extent that it conflicts with the view we have expressed, that case is disapproved.
nevertheless the railroad company is not liable because, under the circumstances here disclosed, the proximate cause of the wife's death was not its negligence, but the negligence of the husband in driving upon the track in the face of the approaching train. The validity of this contention depends altogether upon whether the negligence of the husband constituted an intervening cause which had the effect of turning aside the course of events set in motion by the company, and in and of itself producing the actionable result. The evidence here does not present that situation. Instead of a remote cause and a separate intervening, self-sufficient, proximate cause, we have here concurrent acts, cooperating to produce the result. As this Court pointed out in Washington & Georgetown R. Co. v. Hickey, 166 U. S. 521, 166 U. S. 525, the vice of the argument consists in the attempt to separate into two distinct causes (remote and proximate) what in reality is but one continuous cause -- that is to say, an attempt to separate two inseparable negligent acts which, uniting to produce the result, constituted mutually contributing acts of negligence on the part of the railroad company and the driver of the automobile.
the railroad company or insulate them from the accident, but concurred therewith so as to constitute in point of time and in effect what was essentially one transaction.
The rule is settled by innumerable authorities that, if injury be caused by the concurring negligence of the defendant and a third person, the defendant is liable to the same extent as though it had been caused by his negligence alone.
"It is no defense for a wrongdoer that a third party shared the guilt of the same wrongful act, nor can he escape liability for the damages he has caused on the ground that the wrongful act of a third party contributed to the injury."
Choctaw, O. & G. R. Co. v. Holloway, 114 F. 458, 462. See also Grand Trunk Ry. Co. v. Cummings, 106 U. S. 700, 106 U. S. 702; Gila Valley, G. & N. Ry. Co. v. Lyon, 203 U. S. 465, 203 U. S. 473; Union Pac. Ry. Co. v. Callaghan, 56 F. 988, 993; Chicago, R.I. & P. Ry. Co. v. Sutton, 63 F. 394, 395; Chicago, St.P. & K.C. Ry. Co. v. Chambers, 68 F. 148, 153; Shugart v. Atlanta, K. & N. Ry., 133 F. 505, 510-511; Pacific Telephone & Telegraph Co. v. Hoffman, 208 F. 221, 227; Memphis Consol. Gas & Electric Co. v. Creighton, 183 F. 552, 555.
match was the other. The effect of the former had not ceased, but cooperated with that of the other in effecting the injury. In such case, an inquiry about the proximate cause is not pertinent, for both are liable."

matches: v. v. v. v. v. v. v. v. v. v. v. v. v. v. v. v. v. v. v. v. v. v. v. v. v. v. v.


text:
Abstract: This article attempts to offer a response, from a general perspective, to the question of how culture reveals itself in the application of qualitative research methods in intercultural communication. When we use the term "culture" it is important to bear in mind that culturally attributed social interaction processes are themselves the result of socially constructed processes. They are part of an individual-collective dialectic with multiple potential meanings, which are emergent and in constant reformulation from a wide variety of social and cultural perspectives. Much of the recent research in intercultural communication has been directed towards the study of these systems of culturally related meanings. The literature we review offers perspectives from a variety of disciplines and insights into the role of culture in communication processes.
According to TRIANDIS (2000), research that studies culture and, more specifically, cross-cultural and intercultural communication in its various forms and social contexts, can approach the theoretical foundations and methodological design of their work from three different perspectives: the indigenous one, the cultural one and the cross-cultural one.
The "indigenous" approach focuses on the meaning of concepts in a culture and how such meaning may change across demographics within a given culture context. The focus of such studies is the development of knowledge tailored to a specific culture without any special claims to generality beyond the confines of that particular cultural context. The main challenge with the indigenous approach is the difficulty involved in trying to avoid the influence of pre-given concepts, theories and methodologies and therefore the difficulty of determining what the term indigenous (ADAMOPOLOUS & LONNER, 2001) really means in any given culture.
The "cultural" approach is used to describe those studies which make special use of ethnographic methods. More traditional experimental methods can also be used in conjunction within this approach. Here again the meanings of constructs in a culture are the main focus of attention and there is little of direct comparison of constructs across cultures. The aim is to advance the understanding of the individual in a sociocultural context and to emphasize the importance of culture in understanding his or her behavior. The challenge with this approach is a lack of a widely accepted research methodology (ADAMOPOLOUS & LONNER, 2001).
The researcher play a fundamental role of the in the process of information gathering and data analysis. That is, in qualitative studies the investigator is constituted as the principal instrument in the process of information gathering, in interaction with reality.
We would like to thank Matthias OTTEN for his supervision, contributions and support for the last months of work.
Adamopolous, John & Lonner, Walter (2001). Culture and psychology at a crossroad: Historical perspective and theoretical analysis. In David Matsumoto (Ed.), The handbook of culture and psychology (pp.11-34). New York: Oxford University Press.
Adler, Paul (1975).The transitorial experience: An alternative view of culture shock. Journal of Humanistic Psychology, 15, 3-23.
Ægisdóttir, Stefanía; Gerstein, Lawrence & Canel, Deniz (2008). Equivalence, bias, and translations methodological issues en Cross-Cultural Counseling Research. The Counseling Psychologist, 36(2), 188-219.
Altman, Irwin & Taylor, Dalmas (1973). Social penetration: The development of interpersonal relationships. New York: Holt, Rinehart & Winston.
Andersen, Margaret (1993). Studying across difference. Race, class and gender in qualitative research. In John Stanfield II (Ed.), Race and ethnicity in research methods (pp.39-52). London: Sage.
Aneas, Assumpta (2003). Competencias interculturales transversales en la empresa: un modelo para la detección de necesidades formativas, http://www.tesisenxarxa.net/TDX-1223104-122502/ [Access: 10/10/2007].
Barinaga, Ester (2009). Performative view of language—Methodological considerations and consequences for the study of culture. Forum Qualitative Sozialforschung / Forum: Qualitative Social Research, 10(1), Art. 24, http://nbn-resolving.de/urn:nbn:de:0114-fqs0901244.
Benedict, Ruth (1967). El hombre y la cultura. Buenos Aires: Editorial Sudamericana.
Bennett, Milton (1998). Basic concepts of intercultural communication: Selected readings. Yarmouth: Intercultural Press.
Berger, Charles & Calabrese, Richard (1975). Some explorations in initial interaction and beyond: Toward a developmental theory of interpersonal communication. Human Communication Research, 17, 99-112.
Bhawuk, Dharm & Triandis, Harry (1996). The role of culture theory in the study of culture and intercultural training. In Dan Landis & Richard W. Brislin (Eds.), Handbook of intercultural training (pp.17-34). Thousand Oaks: Sage.
Brislin, Richard; Lonner, Walter & Thorndike, Robert (1973). Cross-cultural research methods. New York: John Wiley.
Busch, Dominic (2009). The notion of culture in linguistic research . Forum Qualitative Sozialforschung / Forum: Qualitative Social Research, 10(1), Art. 50, http://nbn-resolving.de/urn:nbn:de:0114-fqs0901508.
Casmir, Fred (1991). Introduction: Culture, communication, and education. Communication Education, 40, 228-234.
Casmir, Fred (1993). Third-culture building: A paradigm shift for international and intercultural communication. Communication Yearbook, 16, 407-428.
Casmir, Fred (1999). Foundations for the study of intercultural communication based on a third-culture building model. International Journal of Intercultural Relations, 23(1), 91-116.
Chalmers, Alan (1982). ¿Qué es esa cosa llamada ciencia? Una valoración de la naturaleza y el estatuto de la ciencia y sus métodos. Madrid: Siglo XXI.
Chen, Guo-Ming & Starosta, William (1998). Foundations of intercultural communication. Boston: Allyn & Bacon.
Chomsky, Noam (1968). Language and mind. New York: Harcourt Brace.
Coll, César; Marchesi, Álvaro & Palacios, Jesús (1990). Desarrollo psicológico y educación. Madrid: Alianza Editorial.
Condon, John & Yousef, Fathi (1977). An introduction to intercultural communication. Indianapolis: The Bobbs-Merrul Educational Publishing.
Dodd, Charles Harold (1991). Dynamics of intercultural communication. Dubuque, A: Wm.C. Brown Publishers.
Eisner, Elliot (1998). El ojo ilustrado. Indagación cualitativa y mejora de la práctica educativa. Barcelona: Paidós.
Ekman, Paul & Friesen, Wallace (1969). The repertoire of nonverbal behaviour: Categories, origins, usage and coding. Semiotica, 1,49-98.
Erickson, Frederick (1989). Métodos cualitativos de investigación sobre la enseñanza. In Merlin Wittrock (Ed.), La investigación de la enseñanza, II. Métodos cualitativos y de observación (pp.195-301). Barcelona: Paidós/M.E.C.
French, Wendell & Bell, Cecil (1979). Organizational development. New Jersey: Prentice Hall.
Geertz, Clifford (1987). La interpretación de las culturas. Barcelona: Gedisa.
Guba, Egon & Lincoln, Yvonna (1994). Competing paradigms in qualitative research. In Norman Denzin & Yvonna Lincoln (Eds.), Handbook of qualitative research (pp.105-117). London: Sage.
Gudykunst, William (1989). Intercultural communication theory. Current perspectives. Newbury Park: Sage.
Gudykunst, William (1992). Communicating with strangers: An approach to intercultural communication. New York: McGraw-Hill.
Gudykunst, William (1993). Toward a theory of effective interpersonal and intergroup communication. In Richard L. Wiseman & Jolene Koester (Eds.), Intercultural communication competence (pp.33-71). London: Sage.
Gudykunst, William (1994). Bridging differences: Effective intergroup communication (2nd ed.). Thousand Oaks, CA: Sage.
Gudykunst, William & Ting-Toomey, Stella (1988). Culture and interpersonal communication. London: Sage.
Hall, Edward (1959). The silent language. New York: Anchor Books.
Hoffman, David (2009). Multiple methods, communicative preferences and the incremental interview approach protocol. Forum Qualitative Sozialforschung / Forum: Qualitative Social Research, 10(1), Art. 41, http://nbn-resolving.de/urn:nbn:de:0114-fqs0901419.
Keesing, Roger (1974). Theories of culture. Annual Review of Anthropology, 3, 73-97.
Kim, Young-Yun (1977). Communication patterns of foreign immigrants in the process of acculturation. Human Communication Research, 41, 66-76.
Kim, Young-Yun (1988). Contexts of cross-cultural adaptation. In Howard Giles & Cheris Kramarae (Eds.), Communication and cross-cultural adaptation: An integrative theory (pp.3-31). Clevedon: Multilingual Matters.
Kim, Young-Yun (1992). Intercultural communication competence: A systems-theoretic view. In William Gudykunst & Young-Yun Kim (Eds.), Readings on communicating with strangers. An approach to intercultural communication (pp.371-381). New York: McGraw Hill.
Kluckhohn, Clide & Strodtbeck, Fred (1961). Variations in value orientations. Evanston: Row Peterson.
Lincoln, Yvonna & Denzin, Norman (2000). The seventh moment. Out of the past. In Norman Denzin & Yvonna Lincoln (Eds.), Handbook of qualitative research (pp.1047-1065). London: Sage.
Lomas, Carlos; Osorio, Andres & Tusón, Amparo (1993). Ciencias del lenguaje, competencia comunicativas y enseñanza de la lengua. Barcelona: Paidós.
Lustig, Myron & Koester, Jolene (1996). Intercultural competence: Interpersonal communication across cultures. New York: Harper Collins.
Mahadevan, Jasmin (2009). Redefining organizational cultures: An interpretative anthropological approach to corporate narratives. Forum Qualitative Sozialforschung / Forum: Qualitative Social Research, 10(1), Art. 44, http://nbn-resolving.de/urn:nbn:de:0114-fqs0901440.
Malinowski, Bronislaw (1922). The argonauts of the Western Pacific: An account of native enter-prise and adventure in the Archipielagoes of Melanesian New Guinea. London: Routledge.
Otten, Matthias & Geppert, Judith (2009). Mapping the landscape of qualitative research on intercultural communication. A hitchhiker's guide to the methodological galaxy. Forum Qualitative Sozialforschung / Forum: Qualitative Social Research, 10(1), Art. 52, http://nbn-resolving.de/urn:nbn:de:0114-fqs0901520.
Pareek, Udai & Rao, Venkateswara (1980). Cross-cultural surveys and interviewing. In Harry Triandis & John Berry (Eds.), Handbook of cross-cultural psychology, Vol. 2 (pp.127-180). Boston: Allyn & Bacon.
Pedersen, Paul (1994). A handbook for developing multicultural awareness. Alexandria: Americans Counselling Association.
Pedersen, Paul (1997). Culture-centred counselling interventions. Thousand Oaks: Sage.
Rodrigo, Miguel (1999). La comunicación intercultural. Barcelona: Anthropos.
Samovar, Larry; Porter, Richard & Stefani, Lisa (1998). Communication between cultures. Belmont: Wadsworth Publishing Company.
Sandín, M. Paz (2003). Investigación cualitativa en educación. Fundamentos y tradiciones. Madrid: McGraw-Hill.
Schwegler, Ulrike (2009). The challenge of researching trust in intercultural cooperation. Forum Qualitative Sozialforschung / Forum: Qualitative Social Research, 10(1), Art. 48, http://nbn-resolving.de/urn:nbn:de:0114-fqs0901486.
Silverman, David (1997). Qualitative research. Theory, method and practice. London: Sage.
Stanfield II, John (1993). Epistemological considerations. In John Stanfield II (Ed.), Race and ethnicity in research methods (pp.16-36). London: Sage.
Stephan, Walter; Stephan, Cookie & Gudykunst, William (1999). Anxiety in intergroup relations: A comparison of anxiety/uncertainty management theory and integrated threat theory. International Journal of Intercultural Relations, 23(4), 613-628.
Tanaka-Matsumi, Junko (2001). Abnormal psychology and culture. In David Matsumoto (Ed.), The handbook of culture and psychology (pp.265-286). New York: Oxford University Press.
Taylor, Edward (1920 ). Primitive culture. New York: J.P. Putnam’s Sons.
Ting-Toomey, Stella (1984). Qualitative research. An overview. In William Gudykunst & Young-Yu Kim (Eds.), Methods for intercultural communication research (pp.169-184). Beverly Hills: Sage.
Ting-Toomey, Stella (1999). Communicating across cultures. New York: Guilford Press.
Triandis, Harry (2000). Dialectics between cultural and cross-cultural psychology. Asian Journal of Social Psychology, 3, 185-195.
Vila, Ruth (2005). La Competencia Comunicativa Intercultural. Un estudio en el primer ciclo de la ESO. Tesis Doctoral, http://www.tesisenxarxa.net/TDX-1216105-135329/ [Access: 10/10/2007].
Vygotsky, Lev (1977). Pensamiento y lenguaje. Buenos Aires: La Pléyade.
Vygotsky, Lev (1979). El desarrollo de los procesos psicológicos superiores. Barcelona: Crítica.
Wittgenstein, Ludwig (1953). Investigaciones filosóficas. Madrid: Crítica.
María Assumpta ANEAS, Dra. is a member of the research group GREDI (Group of Research on Intercultural Education) at Barcelona University. She is a professor in the Department MIDE (Methods of Research on Education). Her principal research area is that of Intercultural Competences, qualitative research methodologies and the integration of the migration. She is a member of IAIR, and is currently president of SIETAR Spain.
María Paz SANDIN, Dra. is a member of the research group GREDI (Group of Research on Intercultural Education) at Barcelona University. She is a professor in the Department MIDE (Methods of Research on Education). Her research work started in 1992 with research into intercultural education, and during her professional career she has carried out numerous assessments, participated in action research processes as well in participative evaluation ones in secondary schools. In recent years her work has centered on qualitative research methodologies and on the treatment of qualitative data using computer software.
Aneas, María Assumpta & Sandín, María Paz (2009). Intercultural and Cross-Cultural Communication Research: Some Reflections about Culture and Qualitative Methods [57 paragraphs]. Forum Qualitative Sozialforschung / Forum: Qualitative Social Research, 10(1), Art. 51, http://nbn-resolving.de/urn:nbn:de:0114-fqs0901519.

matches:
Art. 24
Art. 50
Art. 41
Art. 44
Art. 52
Art. 48
Art. 51