A receiver for a serial data link, including an analog front end (AFE) including a continuous-time linear equalizer (CTLE) configured to receive an input signal from a transmitter, the CTLE including a first output node; a second output node; a plurality of programmable tail current sources configured to adjust a direct current (DC) offset between the first output node and the second output node; and a calibration circuit including: a slicer configured to output a difference between a first average output voltage corresponding to the first output node and a second average output, voltage corresponding to the second output node; and a calibration counter configured to increment or decrement an offset count based on the difference, wherein the plurality of programmable tail current sources are adjusted based on a value of the offset count.

Methods and systems of performing feed forward equalization (FFE) on data streams are described. A circuitry may generate staggered data streams from data streams of an input signal. The staggered data streams may include data in staggered unit intervals. The circuitry may include a plurality of segments. A segment may define a specific unit interval to carve the staggered data streams into one unit interval pulses positioned at the specific unit interval. The specific unit interval to carve the staggered data streams may indicate an assignment of the segment as one of a FFE pre tap, a FFE main tap, and a FFE post tap. The plurality of segments may be assigned to different FFE taps based on different clock signal selection defining different unit intervals to perform the carving. The plurality of segments may output respective one unit interval pulses to reproduce the input signal.

An antenna system is provided. In one example implementation, the antenna system may include a modal antenna that is operable in a plurality of different modes, and each mode may be associated with a different radiation pattern. The antenna system may include a tuning circuit configured to operate the modal antenna in the plurality of different modes. A transmission line may couple a radio frequency circuit to the modal antenna. The radio frequency circuit may be configured to modulate a control signal onto an RF signal using amplitude-shift keying modulation to generate a transmit signal for communication over the transmission line to the tuning circuit. The tuning circuit may be configured to demodulate the control signal such that the radio frequency circuit can adjust a mode of the modal antenna via the control signal. In some embodiments, the amplitude-shift keying modulation may include on-off keying modulation.

A signal generation device for generating radio frequency, RF, signals, the signal generation device comprising a waveform input for receiving a number of basic waveforms, a control command input for receiving control commands each comprising control information for modifying a respective basic waveform, a RF frontend for transmitting RF signals, and a waveform processor, which based on the control commands modifies the respective basic waveforms and transmits the resulting modified waveforms through the RF frontend.

Disclosed are a dual-path analog-front-end (AFE) circuit and a dual-path signal receiver characterized by high linearity. The dual-path AFE circuit includes a first reception circuit, a second reception circuit and a multiplexer. The first reception circuit is configured to generate a first analog input signal according to a reception signal in a first mode and configured to be coupled to a first constant-voltage terminal via a first switch circuit in a second mode. The second reception circuit is configured to generate a second analog input signal according to the reception signal in the second mode and configured to be coupled to a second constant-voltage terminal via a second switch circuit in the first mode. The multiplexer is configured to output the first analog input signal in the first mode and output the second analog input signal in the second mode.

Techniques are disclosed relating to use of digital predistortion in the context of full-duplex radio. In some embodiments, an apparatus includes one or more antennas and is configured to simultaneously transmit and receive wireless signals via at least partially overlapping frequency resources using the one or more antennas. In some embodiments, the apparatus includes receive chain circuitry that is configured to process both wireless signals transmitted by the apparatus via the one or more antennas and over-the-air wireless signals from one or more other computing devices. In some embodiments, the apparatus includes one or more processing elements configured to determine one or more digital predistortion parameters based on the wireless signals transmitted by the apparatus via the one or more antennas and processed by the receive chain circuitry and apply predistortion to transmitted wireless signals based on the one or more digital predistortion parameters.

A system for time aligning widely frequency spaced signals includes a digital predistortion (DPD) processor and a power amplifier coupled to the DPD processor and operable to provide a transmit signal at a power amplifier output. The system also includes a feedback loop coupled to the power amplifier output. The feedback loop comprises an adaptive fractional delay filter, a delay estimator coupled to the adaptive fractional delay filter, and a DPD coefficient estimator coupled to the delay estimator.

A communication system in which a constellation employing partially anti-symmetric amplitude labels is used to transmit probabilistically shaped amplitudes such that said amplitudes are also used to determine the signs applied thereto for transmission. In an example embodiment, a data transmitter is configured to use a suitable logic function (e.g., an XOR function) to place the parity generated by an FEC code into a selected amplitude bit while using the partially anti-symmetric amplitude labels to avoid placing the parity into the sign bits of the transmitted constellation symbols. In some embodiments, the FEC code can be a low-density parity-check code. Some embodiments are compatible with layered FEC coding, e.g., employing an outer FEC code and an inner FEC code. In some embodiments, FEC coding may be optional. Some embodiments can advantageously be used in communication systems relying on DMT modulation, such as the systems providing DSL access over copper wiring.

A transceiver system compensates for baseline wandering in an analog signal in the analog stage before sampling the analog signal and processing the analog signal in the digital stage. The transceiver system includes an analog to digital converter that samples the analog signal after baseline wandering compensation, a digital equalizer to condition the digital samples, and the slicer to determine transmitted symbols from the digital samples. The transceiver system includes a subtraction block that determines the difference between an input and an output of the slicer, a digital to analog converter that converts a difference between the input and the output of the slicer, a low pass filter that filters out high frequency components of the difference between the input and the output of the slicer thereby to extract out the baseline wandering, and a signal summation circuit that subtracts the baseline wandering from the analog signal.

A multi-beam antenna system, apparatus and method for dynamic carrier aggregation to multi-beam antenna mapping in radio access networks, including small-cell deployments, is disclosed. Apparatus comprises a compact base transceiver unit with integrated multi-beam antenna comprising antenna groups configurable for operation in a plurality of modes, with one or more selected antenna groups enabled, for different use-case scenarios. The base transceiver unit comprises a daisy-chained radio-frequency (RF) system wherein one baseband processor feeds multiple RF transceivers; each RF transceiver front end comprises a software configurable isolation module through which each RF front end is interlinked to previous and next RF front ends to enable dynamic routing of TX/RX data streams through the daisy chain, e.g. routing a transmission data stream from any RF transceiver to any one of the antenna groups or multiple antenna groups, routing a received data stream from one or multiple antenna groups to any RF transceiver, and for contiguous or non-contiguous carrier aggregation.