Abstract: In some embodiments, an attenuator can include a first group of attenuation steps with each attenuation step being configured to switchably provide a first attenuation value, and a second group of attenuation steps with each attenuation step being configured to switchably provide a second attenuation value less than the first attenuation value. The attenuator can be capable of providing a total attenuation value from approximately zero to a sum of the attenuation steps of the first group and the second group in increments of the second attenuation value. With such a configuration, a glitch can have a maximum magnitude that is a difference between the first attenuation value and the second attenuation value during a change in the total attenuation value.

Abstract: Domino circuit and related architectures and methods for carrier aggregation. In some embodiments, a Domino circuit can include first and second signal paths for respective first and second frequency bands, and each signal path can be configured to present an approximately zero impedance to a signal in the other frequency band. The Domino circuit can further include a coupling circuit that couples the first and second signal paths, and configured such that the approximately zero impedance presented by the signal path to the signal in the other frequency band results in the signal in the other frequency band being substantially excluded from the signal path.

Abstract: Apparatus and methods for distributing spurious tones through the frequency domain are disclosed. One such apparatus can include a dithering circuit configured to generate a sequence of numbers that exhibit statistical randomness and a variable frequency circuit configured to adjust a frequency of an output based on the sequence of numbers so as to spread energy of spurious tones in a frequency response of the output to lower a noise floor. In one example, spurious tones can be reduced in a negative voltage generator of a radio frequency (RF) attenuator.

Abstract: Systems, devices and methods related to diversity receivers. In some embodiments, a receiving system can include a controller configured to selectively activate one or more of a plurality of paths between an input and an output, and a plurality of amplifiers, with each one of the plurality of amplifiers disposed along a corresponding one of the plurality of paths and configured to amplify a signal received at the amplifier. The receiving system can further include two or more of features including (a) variable-gain amplifiers, (b) phase-shifting components, (c) impedance matching components, (d) post-amplifier filters, (e) a switching network, and (f) flexible band routing. In some embodiments, such a receiving system can be implemented as a diversity receive (DRx) module.

Abstract: Systems, devices and methods related to radio-frequency (RF) step attenuators. In some embodiments, a step attenuator can include an attenuator circuit having stages connected in series between a first node and a second node. The stages can include a plurality of first attenuation steps with each configured to provide switchable attenuation with a first gain. The stages can further include a plurality of second attenuation steps with each configured to provide switchable attenuation with a second gain. The step attenuator can further include a controller in communication with the attenuator circuit. The controller can be configured to control the switchable attenuation of each of the first attenuation steps and the second attenuation steps.

Abstract: Apparatus and methods for distributing spurious tones through the frequency domain are disclosed. One such apparatus can include a dithering circuit configured to generate a sequence of numbers that exhibit statistical randomness and a variable frequency circuit configured to adjust a frequency of an output based on the sequence of numbers so as to spread energy of spurious tones in a frequency response of the output to lower a noise floor. In one example, spurious tones can be reduced in a negative voltage generator of a radio frequency (RF) attenuator.

Abstract: Diversity receiver front end system with flexible band routing. A receiving system can include a plurality of amplifiers, each one of the plurality of amplifiers disposed along a corresponding one of a plurality of paths between an input of the receiving system and an output of the receiving system and configured to amplify a radio-frequency (RF) signal received at the amplifier. The receiving system can further include an input multiplexer configured to receive one or more RF signals at one or more input multiplexer inputs and to output each of the one or more RF signals to one or more of a plurality of input multiplexer outputs to propagate along a respective one or more of the plurality of paths.

Abstract: Diversity receiver front end system with variable-gain amplifiers. A receiving system can include a controller configured to selectively activate one or more of a plurality of paths between an input of a first multiplexer and an output of a second multiplexer. The receiving system can further include a plurality of bandpass filters, each one of the plurality of bandpass filters disposed along a corresponding one of the plurality of paths and configured to filter a signal received at the bandpass filter to a respective frequency band. The receiving system can further include a plurality of variable-gain amplifiers (VGAs), each one of the plurality of VGAs disposed along a corresponding one of the plurality of paths and configured to amplify a signal received at the VGA with a gain controlled by an amplifier control signal received from the controller.

Abstract: Diversity receiver front end system with flexible antenna routing. A receiving system can include a plurality of amplifiers. Each one of the plurality of amplifiers can be disposed along a corresponding one of a plurality of paths between an input of the receiving system and an output of the receiving system. Each one of the plurality of paths can correspond to a different frequency band. The receiving system can include an input multiplexer configured to receive, at one or more of a plurality of input multiplexer inputs, one or more RF signals. Each one of the one or more RF signals can include one or more frequency bands. The input multiplexer can be configured to output each of the one or more RF signals to one or more of a plurality of input multiplexer outputs.

Abstract: Domino circuit and related architectures and methods for carrier aggregation. In some embodiments, a Domino circuit can include first and second signal paths for respective first and second frequency bands, and each signal path can be configured to present an approximately zero impedance to a signal in the other frequency band. The Domino circuit can further include a coupling circuit that couples the first and second signal paths, and configured such that the approximately zero impedance presented by the signal path to the signal in the other frequency band results in the signal in the other frequency band being substantially excluded from the signal path.

Abstract: A low noise receiver includes a downconverter configured to receive a radio frequency (RF) signal, the downconverter comprising a switching architecture configured to generate a plurality of output phases based on a respective plurality of local oscillator (LO) signals, a differencing circuit configured to combine the plurality of output phases such that an nth output phase is differenced with an (n+K)th output phase, resulting in gain-added output phases, and a summation filter configured to receive the gain-added output phases and configured to combine the gain-added output phases such that a response of the receiver effectively reduces odd harmonics of the RF signal.

Abstract: Various implementations include circuits, devices and/or methods that enable tuning a multi-band antenna such that two or more of the bands are tuned independently of one another, whereby tuning one band is decoupled from tuning another band. Some implementations include a multi-band tuning arrangement having first and second tunable two-terminal circuits. The first tunable two-terminal circuit has a low transmission impedance associated with a first frequency band, and a high transmission impedance associated with a second frequency band, the first tunable two-terminal circuit including a first control element to selectively adjust a first resonant frequency associated with the first frequency band.

Abstract: Circuits and methods related to radio-frequency (RF) receivers having carrier aggregation. In some embodiments, a carrier aggregation (CA) circuit can include a first filter configured to allow operation in a first frequency band, and a second filter configured to allow operation in a second frequency band. The CA circuit can further include a first path implemented between the first filter and a common node, with the first path being configured to provide a substantially matched impedance for the first frequency band and a substantially open-circuit impedance for the second frequency band. The CA circuit can further include a second path implemented between the second filter and the common node, with the second path being configured to provide a substantially matched impedance for the second frequency band and a substantially open-circuit impedance for the first frequency band.

Abstract: Systems, devices and methods related to radio-frequency (RF) step attenuators. In some embodiments, a step attenuator can include an attenuator circuit having stages connected in series between a first node and a second node. The stages can include a plurality of first attenuation steps with each configured to provide switchable attenuation with a first gain. The stages can further include a plurality of second attenuation steps with each configured to provide switchable attenuation with a second gain. The step attenuator can further include a controller in communication with the attenuator circuit. The controller can be configured to control the switchable attenuation of each of the first attenuation steps and the second attenuation steps.

Abstract: A low noise receiver includes a downconverter configured to receive a radio frequency (RF) signal, the downconverter comprising a switching architecture configured to generate a plurality of output phases based on a respective plurality of local oscillator (LO) signals, a differencing circuit configured to combine the plurality of output phases such that an nth output phase is differenced with an (n+K)th output phase, resulting in gain-added output phases, and a summation filter configured to receive the gain-added output phases and configured to combine the gain-added output phases such that a response of the receiver effectively reduces odd harmonics of the RF signal.

Abstract: An ‘L’ shaped dynamically configurable impedance matching circuit is presented herein. The circuit can include a series element and a shunt element. The shunt element in the L-shaped impedance matching circuit can be moved or modified based on the impedance of the circuit elements in electrical communication with each side of the impedance matching circuit. Thus, in some cases, the impedance matching circuit may be a flexible circuit that can be dynamically modified based on the environment or configuration of the wireless device that includes the impedance matching circuit.

Abstract: Apparatus and methods for distributing spurious tones through the frequency domain are disclosed. One such apparatus can include a dithering circuit configured to generate a sequence of numbers that exhibit statistical randomness and a variable frequency circuit configured to adjust a frequency of an output based on the sequence of numbers so as to spread energy of spurious tones in a frequency response of the output to lower a noise floor. In one example, spurious tones can be reduced in a negative voltage generator of a radio frequency (RF) attenuator.

Abstract: Apparatus and methods for distributing spurious tones through the frequency domain are disclosed. One such apparatus can include a dithering circuit configured to generate a sequence of numbers that exhibit statistical randomness and a variable frequency circuit configured to adjust a frequency of an output based on the sequence of numbers so as to spread energy of spurious tones in a frequency response of the output to lower a noise floor. In one example, spurious tones can be reduced in a negative voltage generator of a radio frequency (RF) attenuator.

Abstract: A system for transmitting and receiving data is provided. The system includes a direct-conversion receiver that receives a signal modulated on a carrier frequency signal. The direct-conversion receiver includes one or more subharmonic local oscillator mixers. A local oscillator is connected to the direct conversion receiver, and generates a signal having a frequency equal to a subharmonic of the carrier frequency signal. A transmitter is connected to the local oscillator, which uses the local oscillator signal to transmit outgoing data.

Abstract: A controller and a circuit work together to enable a selective and dynamic adjustment to correct phase and gain imbalances in quadrature signal paths of a receiver. Under select conditions, it has been determined that statistical estimates of gain and phase imbalance can be applied to adjust signals in the quadrature signal paths of a receiver. The controller validates the select conditions before updating the estimate of the gain imbalance and the estimate of the phase imbalance. The controller directs a compensator under select operating conditions such that validated dynamic estimates of the gain and phase imbalance or calibration data is applied to the quadrature signal paths. The controller disables the compensator and enables an estimator and a calculator when estimates are unavailable for the present operating conditions.