Abstract: For small cells, transceivers demand high performance while maintaining system efficiency. The present disclosure describes a highly integrated cellular transceiver that offers such features by providing one or more digital functions on-chip, onto the same die in the cellular transceiver. Effectively, the scope and boundary of the cellular transceiver is expanded to move beyond the data converters of the transceiver to include a variety of digital functions, thus integrating more of the signal chain in the cellular transceiver. Integration can greatly reduce complexity for the baseband processing, lower the cost of the overall transceiver system, reduce power consumption, and at the same time, benefit from improvements on the digital functions through integration.

Abstract: Otherwise incompatible digital predistortion and uptilt can be used together, such as in a cable television or other cable communications system having a frequency-dependent signal loss at high frequencies. The predistortion can be used to compensate for a nonlinear gain compression of a power amplifier at higher frequencies. Additional uptilt and equalizer circuits can be included to address deleterious distortion effects that may otherwise arise by using predistortion and uptilt together. Training and adaptation of various components are described. Fine and coarse uptilt adjustments can be provided.

Abstract: An envelope tracking scheme can be used, such as to modulate a supply node of a power amplifier circuit to improve efficiency. For example, a magnitude or amplitude envelope of a signal to be modulated can be scaled and used to drive a node, such as a drain, of the power amplifier circuit. An envelope tracking signal can be generated such as having a bandwidth that is compressed as compared to a full-bandwidth envelope signal. A peak-value “look ahead” technique can be used, for example, so that amplitude compression or clipping of the transmit signal is suppressed when the bandwidth-compressed envelope tracking signal is used to modulate a supply node of the power amplifier used to amplify the transmit signal.

Abstract: For small cells, transceivers demand high performance while maintaining system efficiency. The present disclosure describes a highly integrated cellular transceiver that offers such features by providing one or more digital functions on-chip, onto the same die in the cellular transceiver. Effectively, the scope and boundary of the cellular transceiver is expanded to move beyond the data converters of the transceiver to include a variety of digital functions, thus integrating more of the signal chain in the cellular transceiver. Integration can greatly reduce complexity for the baseband processing, lower the cost of the overall transceiver system, reduce power consumption, and at the same time, benefit from improvements on the digital functions through integration.

Abstract: A digital pre-distortion system can inversely model a power amplifier of a system to linearize the transmitter. A complex baseband model for digital pre-distortion based on a narrowband signal assumption is unworkable for an ultra wide band Cable television application. Predistortion can use a true wide band model including real-valued basis terms, obtained from a real-valued signal. When raised to a power, both even and odd harmonics or both odd or even other non-linear terms are represented and negative frequency fold-over can be accounted for. A Hilbert transform can be applied. Compressed sensing can be used to reduce the number of basis terms in the true real wide band model to generate a sparse model. Sparse equalization can be added to improve the stability of the digital pre-distortion system.

Abstract: Otherwise incompatible digital predistortion and uptilt can be used together, such as in a cable television or other cable communications system having a frequency-dependent signal loss at high frequencies. The predistortion can be used to compensate for a nonlinear gain compression of a power amplifier at higher frequencies. Additional uplift and equalizer circuits can be included to address deleterious distortion effects that may otherwise arise by using predistortion and uptilt together. Training and adaptation of various components are described. Fine and coarse uptilt adjustments can be provided.

Abstract: Embodiments of the present invention may provide a method of measuring an unknown capacitance of a device. The method may comprise the steps of driving a test signal to a circuit system that includes a current divider formed by the device with unknown capacitance and a reference capacitor; mirroring a current developed in the reference capacitor to a second circuit system that includes a measurement impedance; measuring a voltage within the second circuit system; and deriving a capacitance of the unknown capacitance based on the measured voltage with reference to a capacitance of the reference capacitor and the measurement impedance.

Abstract: For small cells, transceivers demand high performance while maintaining system efficiency. The present disclosure describes a highly integrated cellular transceiver that offers such features by providing one or more digital functions on-chip, onto the same die in the cellular transceiver. Effectively, the scope and boundary of the cellular transceiver is expanded to move beyond the data converters of the transceiver to include a variety of digital functions, thus integrating more of the signal chain in the cellular transceiver. Integration can greatly reduce complexity for the baseband processing, lower the cost of the overall transceiver system, reduce power consumption, and at the same time, benefit from improvements on the digital functions through integration.

Abstract: Embodiments of full duplex radios are disclosed herein. For example, a radio may include: a first transmitter, a second transmitter, and a receiver. The first transmitter may be configured to receive an input signal, process the input signal to generate a first transmit signal, and transmit the first transmit signal. The second transmitter may be configured to receive the input signal, process the input signal to generate a second transmit signal, and couple the second transmit signal into an input path of the receiver. Leakage at the receiver may thus be reduced. Some embodiments of a radio may also include a base band correction circuit and means for reducing transmitter noise that leaks into the receiver.

Abstract: In a multi transmitter-receiver system, transmitter noise cancellation may be applied selectively for certain transmitters by exploiting asymmetries of the system. Hence, observation receiver(s) numbering less than the number of transmitters may be provided saving space and cost. Each observation receiver may selectively couple to a transmitter path and estimate the leakage noise from that transmitter. Based on the estimated leakage noise, noise cancellation may be applied to corresponding receiver path(s). Selection of the transmitters for leakage estimation may be based on system conditions at that time, which may be known to the system or may be estimated dynamically.

Abstract: Embodiments of the present invention may include power amplifier architectures and systems for use in wireless communication systems. The systems may include a first circuit path for receiving an input signal and decomposing the signal into two vector signals using an out-phasing generator, modifying the vectors based on predetermined value limit, amplifying the vectors using power amplifiers, and combining the vectors to provide an amplified output. The system may include a second circuit path for generating an estimate of an envelope of the input signal and using the envelope to modulate the voltage supplies of the power amplifiers when amplifying the vector signals. The system may also include a feedback path for sending information regarding the envelope of the input signal into the out-phasing generator, which may modify the vector signals in response thereto.

Abstract: An all digital model of nonlinear transmitter signal distortion in signals received at a receiver of a transmitter-receiver may be used to estimate distortion. The estimated distortion may then be cancelled from the received signals to improve signal quality of the received signal. The digital nonlinear model may be part of an estimator circuit that estimates nonlinear distortion terms by applying a formula or transformation to a digitized version of the signals transmitter at a transmitter of the transmitter-receiver. A mixer may be used to shift a frequency of the estimated nonlinear terms away from a transmitter frequency so that the nonlinear terms can later be subtracted from the incoming signal received at the receiver at a receiver frequency. Circuits and methods are provided.

Abstract: A calibration signal generator for use in a balancing circuit calibration device in a radio receiver, the calibration signal generator comprising: a means of amplifying a clocking signal from a clocking signal generator to provide a first calibration signal; a means of generating a second calibration signal from the clocking signal, the first and second calibration signals being transmissible to a one or more mixing circuits in the balancing circuit calibration device; and a means synchronizing the operation of other circuit elements in the balancing circuit calibration device with the clocking signal; characterized in that the clocking signal generator is present in the radio receiver and used therein for other functions.

Abstract: Embodiments of the present invention may include power amplifier architectures and systems for use in wireless communication systems. The systems may include a first circuit path for receiving an input signal and decomposing the signal into two vector signals using an out-phasing generator, modifying the vectors based on predetermined value limit, amplifying the vectors using power amplifiers, and combining the vectors to provide an amplified output. The system may include a second circuit path for generating an estimate of an envelope of the input signal and using the envelope to modulate the voltage supplies of the power amplifiers when amplifying the vector signals. The system may also include a feedback path for sending information regarding the envelope of the input signal into the out-phasing generator, which may modify the vector signals in response thereto.

Abstract: An integrated circuit comprising processing logic for operably coupling to radio frequency (RF) receiver circuitry arranged to receive a wireless network signal. The receiver circuitry generates in-phase and quadrature digital baseband representations of the wireless network signal. The processing logic determines quadrature (I/Q) imbalance of the RF receiver circuitry based on the in-phase and quadrature digital baseband representations of the wireless network signal.

Abstract: A predetermined nonlinearity may be introduced between a digital predistorter and a power amplifier of a RF transmitter. The nonlinearity may be applied to an output of a digital predistorter. The application of the nonlinearity to the predistorter output may expand a bandwidth of the predistorter output from a first lower bandwidth to a higher second bandwidth of the power amplifier that may be needed to support a predetermined data transfer rate at the RF transmitter. Introducing this nonlinearity between the predistorter and the power amplifier may reduce the sampling rate and power requirements of components included as part of a predistortion device. As a result less noise may be generated and less power may be consumed, resulting in smaller, more efficient, and more accurate predistortion and/or RF transmission systems.

Abstract: In a multi transmitter-receiver system, transmitter noise cancellation may be applied selectively for certain transmitters by exploiting asymmetries of the system. Hence, observation receiver(s) numbering less than the number of transmitters may be provided saving space and cost. Each observation receiver may selectively couple to a transmitter path and estimate the leakage noise from that transmitter. Based on the estimated leakage noise, noise cancellation may be applied to corresponding receiver path(s). Selection of the transmitters for leakage estimation may be based on system conditions at that time, which may be known to the system or may be estimated dynamically.

Abstract: An all digital model of nonlinear transmitter signal distortion in signals received at a receiver of a transmitter-receiver may be used to estimate distortion. The estimated distortion may then be cancelled from the received signals to improve signal quality of the received signal. The digital nonlinear model may be part of an estimator circuit that estimates nonlinear distortion terms by applying a formula or transformation to a digitized version of the signals transmitter at a transmitter of the transmitter-receiver. A mixer may be used to shift a frequency of the estimated nonlinear terms away from a transmitter frequency so that the nonlinear terms can later be subtracted from the incoming signal received at the receiver at a receiver frequency. Circuits and methods are provided.

Abstract: Transmitter noise cancellation may be applied on a channel by channel basis to active channels of an incoming radio frequency signal received at a receiver. A noise cancellation filter may be provided for each active channel in a predetermined signal band. Applying noise cancellation on a per active channel basis instead of to the entire receive band may substantially reduce the filtering requirement and number of filter coefficients or taps to save power and reduce manufacturing costs. Channelized transmitter noise cancellers, multi transmitter-receiver cross coupling cancellers, and hybrid full signal band and channelized transmitter noise cancellers are also provided.

Abstract: A wireless communication unit comprises a transmitter having a forward path comprising a power amplifier, PA, and a feedback path operably coupled to the power amplifier, wherein the feedback path comprises a coupler arranged to feed back a portion of a signal to be transmitted and a controller logic module arranged to control a power control value of the power amplifier, such that the forward path and feedback path form a closed loop power control. The controller logic module is arranged to determine a gain variation in the transmitter and provide attenuation to a transmit signal passing therethrough on a transmit slot by transmit slot basis and instruct a power backoff where necessary.