Ultra-Wideband (UWB) technology is a wireless technology for the transmission of large amounts of digital data as modulated coded impulses over a very wide frequency spectrum with very low power over a short distance. However, to support their deployment in a wide range of applications it would be beneficial to provide solutions which: exploit multiple directive antennas oriented in different directions to ensure spatial filtering of undesired signals and increase signal strength; exploit dynamic configuration of the multi-pulse bundles employed to transmit the bits/symbols within the packets to enhance link quality of service; exploit dynamic configuration of the band or bands which the transmitter operates upon; and exploit antenna sub-systems providing omnidirectional radiation patterns with implementations offering filtering and balun functions with small footprint and low cost.

A receiver (e.g., for a 10G fiber communications link) includes an interleaved ADC coupled to a multi-channel equalizer that can provide different equalization for different ADC channels within the interleaved ADC. That is, the multi-channel equalizer can compensate for channel-dependent impairments. In one approach, the multi-channel equalizer is a feedforward equalizer (FFE) coupled to a Viterbi decoder, for example a sliding block Viterbi decoder (SBVD); and the FFE and/or the channel estimator for the Viterbi decoder are adapted using the LMS algorithm.

Envelope tracking systems for power amplifiers are provided herein. In certain embodiments, an envelope tracker is provided for a power amplifier that amplifies a radio frequency (RF) signal. The envelope tracker controls a power amplifier supply voltage of the power amplifier based on an envelope signal indicating an envelope of the RF signal. The envelope tracker includes a first controllable resistance between a first regulated voltage and the power amplifier supply voltage and a second controllable resistance between a second regulated voltage and the power amplifier supply voltage. The first regulated voltage and the second regulated voltage are of different voltage levels.

A receiver (e.g., for a 10G fiber communications link) includes an interleaved ADC coupled to a multi-channel equalizer that can provide different equalization for different ADC channels within the interleaved ADC. That is, the multi-channel equalizer can compensate for channel-dependent impairments. In one approach, the multi-channel equalizer is a feedforward equalizer (FFE) coupled to a Viterbi decoder, for example a sliding block Viterbi decoder (SBVD); and the FFE and/or the channel estimator for the Viterbi decoder are adapted using the LMS algorithm.

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.

The present invention is a computationally-efficient compensator for removing nonlinear distortion. The compensator operates in a digital post-compensation configuration for linearization of devices or systems such as analog-to-digital converters and RF receiver electronics. The compensator also operates in a digital pre-compensation configuration for linearization of devices or systems such as digital-to-analog converters, RF power amplifiers, and RF transmitter electronics. The compensator effectively removes nonlinear distortion in these systems in a computationally efficient hardware or software implementation by using one or more factored multi-rate Volterra filters. Volterra filters are efficiently factored into parallel FIR filters and only the filters with energy above a prescribed threshold are actually implemented, which significantly reduces the complexity while still providing accurate results. For extremely wideband applications, the multi-rate Volterra filters are implemented in a demultiplexed polyphase configuration which performs the filtering in parallel at a significantly reduced data rate. The compensator is calibrated with an algorithm that iteratively subtracts an error signal to converge to an effective compensation signal. The algorithm is repeated for a multiplicity of calibration signals, and the results are used with harmonic probing to accurately estimate the Volterra filter kernels. The compensator improves linearization processing performance while significantly reducing the computational complexity compared to a traditional nonlinear compensator.

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.

A system includes a crest-factor reduction circuit, a signal analyzer, and a pre-distortion circuit. The crest-factor reduction circuit reduces a crest factor of a baseband signal and generates a feedforward signal. The signal analyzer generates parameters based on the feedforward signal and an output signal from a power amplifier. The pre-distortion circuit generates a pre-distorted baseband signal based on the parameters for input to the power amplifier.

Envelope tracking can be employed to reduce power consumption of a power amplifier, but envelope tracking can introduce nonlinearities to a power amplifier. These nonlinearities can manifest themselves as noise at the output of the power amplifier. Embodiments described herein provide techniques for characterizing a parameter indicative of power amplifier noise when envelope tracking is employed. Measurement of this parameter can permit power amplifier designers to decide whether to forgo envelope tracking if a power amplifier is too susceptible to such noise, redesign the power amplifier to improve compatibility with envelope tracking, or to employ distortion compensation circuitry to reduce the noise output by the power amplifier. Counterintuitively, this distortion compensation circuitry may involve increasing the power, such as the envelope tracking power supply. However, increasing the power may be a desirable trade-off for increased linearity.

RF coupling circuitry includes a first coupled signal output node, a second coupled signal output node, an RF coupler, RF filtering circuitry, and attenuator circuitry. The RF coupler is configured to couple RF signals from an RF transmission line to provide coupled RF signals. The RF filtering circuitry is coupled to the RF coupler and configured to separate RF signals within a first RF frequency band in the coupled RF signals from RF signals within a second RF frequency band in the coupled RF signals. The attenuator circuitry is coupled between the RF filtering circuitry, the first coupled signal output node, and the second coupled signal output node. The attenuator circuitry is configured to attenuate the RF signals within the first RF frequency band and the RF signals within the second RF frequency band.