Abstract: An asymmetrical transformer output demultiplexing (ATODEM) circuit is disclosed. The ATODEM circuit of the present disclosure includes N input windings, wherein N is a natural number. Each of the N input windings have input terminals that couple to output terminals of N PAs. The ATODEM further includes M output ports wherein M is a natural number, each of the M output ports having N series coupled windings coupled between a load terminal and a return terminal. The physical attributes of the N input windings, and the N series coupled windings of the M output ports are asymmetrical such that in an Nth operation mode an Nth PA first-load line impedance matches an output impedance of an Nth PA coupled to the input terminals.

Abstract: The embodiments disclosed in the detailed description include a power amplifier having a low power mode amplifier, a medium power mode amplifier, and a high power mode amplifier in communication with a radio frequency (RF) output load. The exemplary embodiments of the power amplifier permit a wireless device to select the most power efficient means to transmit an RF signal based upon the desired output power level.

Abstract: The present invention relates to a frequency-adjustable radio frequency (RF) isolator that may operate as a bandpass filter when processing RF signals in a forward direction and may operate as a notch filter when processing RF signals in a reverse direction. The notch filter has a notch frequency, which is adjustable to provide adequate isolation from reflected signals at a specific operating frequency. The frequency-adjustable RF isolator may include an electro-magnetic gyrator coupled to a variable impedance circuit, which may present a variable impedance to the electro-magnetic gyrator. The notch frequency may be dependent on the variable impedance. The notch filter may be a single-notch filter or may be a multiple-notch filter.

Abstract: The present disclosure relates to de-multiplexing at least one RF input signal feeding RF power amplifier circuitry to create multiple de-multiplexed RF output signals, which may be used to provide RF transmit signals in an RF communications system. Output transformer circuitry is coupled to outputs from the RF power amplifier circuitry to provide the de-multiplexed RF output signals, which may support multiple modes, multiple frequency bands, or both. The de-multiplexed RF output signals may be used in place of RF switching elements in certain embodiments. As a result, RF front-end switching circuitry in the RF communications system may be simplified, thereby reducing insertion losses, reducing costs, reducing size, or any combination thereof. Additionally, the output transformer circuitry may provide load line transformation, output transistor biasing, or both to the RF power amplifier circuitry.

Abstract: An adaptive antenna neutralization network (AANN) for neutralizing coupling between a first antenna and a second antenna of a mobile terminal is disclosed. The AANN includes an array of reactive branches. Each of the reactive branches includes a reactive element and an electrically controlled switch with a control input for selectively coupling the reactive element between the first antenna and the second antenna. Also included is a switch driver having an output coupled to the control input of each electrically controlled switch, and a controller having an output for sending control signals to the switch driver to turn on or off individual ones of the electrically controlled switches in response to conditions that indicate a coupling state between the first antenna and the second antenna.

Abstract: A signal line sharing protocol and hardware permit control of a remotely located active device configured to provide different load configurations to an antenna. As an example, the communication system may include a master device. The master device may include a general purpose output and a radio frequency port. The communication system may further include a first duplexer and a second duplexer. The first duplexer may include a first port, a second port, and a third port, where the second port is coupled to the radio frequency port and the third port is coupled to the general purpose output of the master device. The second duplexer may include a first port, a second port, and a third port, where the first port of the second duplexer is in communication with the first port of the first duplexer, wherein the second port is coupled to an antenna, and where the third port is in communication with a slave device. The slave device may be coupled to the antenna.

Abstract: Embodiments of the present invention include amplitude-modulated or polar-modulated radio frequency (RF) power amplifier circuitry, in which an envelope power supply input to an RF power amplifier is powered by a pre-distorted amplitude modulation (AM) power supply. The pre-distorted AM power supply receives an AM signal, which is then pre-distorted and amplified to provide an AM power supply signal to the RF power amplifier. The pre-distortion of the AM signal is used to improve the linearity, the efficiency, or both, of the RF power amplifier. The pre-distortion provides a feed-forward system, which may allow use of a reduced bandwidth pre-distorted AM signal to an AM power supply and a reduced bandwidth AM power supply, which may increase efficiency.

Abstract: Pilot switch circuitry coupled across first and second terminals of a microelectromechanical system (MEMS) switch is provided to reduce or eliminate arcing between a cantilever contact and a terminal contact when the MEMS switch is opened or closed. The pilot switch circuitry establishes a common potential at the first and second terminals prior to, and preferably until, the cantilever contact and terminal contact come into contact with one another when the MEMS switch is closed. The pilot switch circuitry may also establish a common potential at the first and second terminals prior to, and preferably after, the cantilever contact and terminal contact separate from one another when the MEMS switch is opened.

Abstract: Power control circuitry is provided for controlling an output power of a transmitter of a mobile terminal operating according to a continuous time transmit scheme such as Wideband Code Division Multiple Access (WCDMA). Transmit circuitry processes a quadrature baseband signal to provide a radio frequency transmit signal. The radio frequency transmit signal is coupled to the power control circuitry via a coupler and processed to provide a feedback amplitude signal. The power control circuitry operates to remove an amplitude modulation component from the feedback signal using a reference amplitude signal generated from the quadrature baseband signal, thereby providing a measured gain signal of the transmit circuitry. Based on the measured gain signal and a target output power, the power control circuitry operates to control a gain of the transmit circuitry such that the output power of the transmit circuitry is within a predetermined range about the target output power.

Abstract: The present invention is a split band duplexer, which increases the separation between a transmit passband and a receive passband by splitting the transmit and receive passbands into sub-bands. Each sub-band has a bandwidth that is less than the bandwidth of the full passband. The increased separation increases isolation margins and insertion loss margins, which allows use of standard filter components, such as surface acoustic wave (SAW) filters, and their accompanying manufacturing tolerances and drift characteristics. In one embodiment of the present invention, the split band duplexer includes a first sub-band duplexer and a second sub-band duplexer. The first sub-band duplexer may provide a full bandwidth transmit passband and a receive passband that is less than full bandwidth. The second sub-band duplexer may provide a full bandwidth receive passband and a transmit passband that is less than full bandwidth.

Abstract: A modulator for a multimode wireless transmitter is provided. In general, the modulator has three modes of operation: an Enhanced Data Rates for Global System for Mobile Communications Evolution (EDGE) mode, which may be referred to as an 8-Level Phase Shift Keying (8PSK) mode; a Gaussian Minimum Shift Keying (GMSK) mode; and a Wideband Code Division Multiple Access (WCDMA) mode.

Abstract: A Wideband Code-Division Multiple Access (WCDMA) transceiver and a method of operating the same. In one embodiment, the transceiver includes: (1) a transmit chain having a lookup table that provides coefficients to a digital predistorter based on power indicators and (2) a predistorter training circuit, coupled to the transmit chain, that employs a receive chain of the WCDMA transceiver to provide a digital compensation signal that is a function of an output of the transmit chain and employs both the power indicators and the digital compensation signal to cause the lookup table to provide alternative coefficients to the digital predistorter thereby to reduce distortion in the output.

Abstract: Power control circuitry is provided for controlling an output power of a transmitter of a mobile terminal operating according to a continuous time transmit scheme such as Wideband Code Division Multiple Access (WCDMA). Transmit circuitry processes a quadrature baseband signal to provide a radio frequency transmit signal. The radio frequency transmit signal is coupled to the power control circuitry via a coupler and processed to provide a feedback amplitude signal. The power control circuitry operates to remove an amplitude modulation component from the feedback signal using a reference amplitude signal generated from the quadrature baseband signal, thereby providing a measured gain signal of the transmit circuitry. Based on the measured gain signal and a target output power, the power control circuitry operates to control a gain of the transmit circuitry such that the output power of the transmit circuitry is within a predetermined range about the target output power.

Abstract: An adaptive predistortion system for use with a power amplifier having a nonlinear amplification characteristic and a method of adaptively predistorting a signal is provided. In one embodiment, the adaptive predistortion system includes a coefficient update subsystem coupled to an output of the power amplifier and configured to update a set of predistortion coefficients using an iterative process based on an output signal of the power amplifier. Additionally, the adaptive predistortion system includes a predistortion filter subsystem coupled to the coefficient update subsystem and configured to employ the set of predistortion coefficients to reduce a level of distortion associated with the nonlinear amplification characteristic.

Abstract: An adaptive predistortion system for use with a power amplifier having a nonlinear amplification characteristic and a method of adaptively predistorting a signal is provided. In one embodiment, the adaptive predistortion system includes a coefficient update subsystem coupled to an output of the power amplifier and configured to update a set of predistortion coefficients using an iterative process based on an output signal of the power amplifier. Additionally, the adaptive predistortion system includes a predistortion filter subsystem coupled to the coefficient update subsystem and configured to employ the set of predistortion coefficients to reduce a level of distortion associated with the nonlinear amplification characteristic.

Abstract: A Wideband Code-Division Multiple Access (WCDMA) transceiver and a method of operating the same. In one embodiment, the transceiver includes: (1) a transmit chain having a lookup table that provides coefficients to a digital predistorter based on power indicators and (2) a predistorter training circuit, coupled to the transmit chain, that employs a receive chain of the WCDMA transceiver to provide a digital compensation signal that is a function of an output of the transmit chain and employs both the power indicators and the digital compensation signal to cause the lookup table to provide alternative coefficients to the digital predistorter thereby to reduce distortion in the output.