Abstract: Apparatus and methods for transceivers are provided herein. In a first aspect, an observation receiver is implemented to detect common-mode local oscillator (LO) leakage while the observation receiver performs other functions. In a second aspect, a transceiver is implemented with an LO leakage compensation circuit that compensates a transmitter for LO leakage using a digital filter, such as a Kalman filter, that combines differential LO leakage observations with common-mode LO leakage observations. In a third aspect, a transmitter includes multiple local loopback paths including a first loopback path after a variable gain amplifier (VGA) and a second loopback path before the VGA.

Abstract: Systems and methods are provided for operating an electrolyzer. The systems and methods perform operations comprising obtaining a plurality of impedance measurements of the plurality of electrolytic cells at a plurality of frequencies; tracking changes to the plurality of impedance measurements of the plurality of electrolytic cells over a time period; and generating, based on the changes to the plurality of impedance measurements, a model representing operating conditions of the electrolytic cells on an individual electrolytic cell basis.

Abstract: Various examples are directed to a solar power electrolyzer system comprising a first electrolyzer stack, a second electrolyzer stack, a first converter and a first converter controller. The first electrolyzer stack may be electrically coupled in series with a photovoltaic array. The first converter may be electrically coupled in series with the first electrolyzer stack and electrically coupled in series with the photovoltaic array. The second electrolyzer stack electrically may be coupled at an output of the first converter. The first converter controller may be configured to control a current gain of the first converter.

Abstract: Various examples are directed to a solar power electrolyzer system comprising a first electrolyzer stack, a second electrolyzer stack, a first converter and a first converter controller. The first electrolyzer stack may be electrically coupled in series with a photovoltaic array. The first converter may be electrically coupled in series with the first electrolyzer stack and electrically coupled in series with the photovoltaic array. The second electrolyzer stack electrically may be coupled at an output of the first converter. The first converter controller may be configured to control a current gain of the first converter.

Abstract: Radio transmitters providing an analog signal with both radio frequency (RF) and baseband frequency information are disclosed herein. In certain embodiments, a transmitter for an RF communication system includes a radio frequency digital-to-analog converter (RFDAC) that outputs the analog signal with two bands of content. In particular, the analog signal includes a first band on content at RF frequency and representing the RF signal for transmission, and a second band of content at baseband frequency and representing baseband information such as the envelope of the RF signal.

Abstract: Transconductor circuits with programmable tradeoff between bandwidth and flicker noise are disclosed. An example circuit includes an input port, an output port, a plurality of transistors, and a switch arrangement that includes a plurality of switches, configured to change coupling between the input port, the output port, and the transistors to place the transconductor circuit in a first or a second mode of operation. An input capacitance of the transconductor circuit operating in the first mode is larger than when the transconductor circuit is operating in the second mode. In the first mode, having a larger input capacitance results in a decreased flicker noise because the amount of flicker noise is inversely proportional to the input capacitance. In the second mode, having a smaller input capacitance leads to an increased flicker noise but that is acceptable for wide-bandwidth applications because wide-bandwidth signals may be less sensitive to flicker noise.

Abstract: Various examples are directed to a solar power electrolyzer system comprising a first electrolyzer stack, a second electrolyzer stack, a first converter and a first converter controller. The first electrolyzer stack may be electrically coupled in series with a photovoltaic array. The first converter may be electrically coupled in series with the first electrolyzer stack and electrically coupled in series with the photovoltaic array. The second electrolyzer stack electrically may be coupled at an output of the first converter. The first converter controller may be configured to control a current gain of the first converter.

Abstract: Embodiments of the present disclosure relate to cellular technology applications of beamforming performed in the digital domain. In one aspect, an RF system for performing digital beamforming on a per-carrier basis is disclosed, where different phase and/or amplitude adjustments are applied to signals of different frequency ranges (i.e., to different carrier signals). In another aspect, an RF system for performing digital beamforming on a per-antenna basis is disclosed, where different phase and/or amplitude adjustments are applied to signals transmitted from or received by different antennas. In some embodiments, an RF system may be configured to implement both digital beamforming on a per-carrier basis and digital beamforming on a per-antenna basis. The RF systems disclosed herein allow implementing programmable beamforming in the digital domain in a manner that is significantly less complex than conventional implementations.

Abstract: Systems and methods are provided for operating an electrolyzer. The systems and methods include operations comprising: forming an electrical series connection through the plurality of electrolytic cells; bypassing a first electrolytic cell using bypass circuitry included in a first bipolar plate to electrically remove the first electrolytic cell from the electrical series connection while maintaining flow of current through a second of electrolytic cell; monitoring one or more parameters of the plurality of electrolytic cells; and generating, based on the one or more parameters, a model representing operating conditions of the electrolytic cells on an individual electrolytic cell basis.

Abstract: Systems and methods are provided for operating an electrolyzer. The electrolyzer comprising a plurality of electrolytic cells, each of the electrolytic cells comprising an electrolyte and two electrodes, the systems and methods comprising: a common voltage converter coupled in parallel to the plurality of electrolytic cells and configured to distribute power to the plurality of electrolytic cells; and control circuitry coupled to the plurality of electrolytic cells, the control circuitry configured to: monitor one or more parameters of the plurality of electrolytic cells; and generate, based on the one or more parameters, a model representing operating conditions of the electrolytic cells on an individual electrolytic cell basis.

Abstract: Transconductor circuits with programmable tradeoff between bandwidth and flicker noise are disclosed. An example circuit includes an input port, an output port, a plurality of transistors, and a switch arrangement that includes a plurality of switches, configured to change coupling between the input port, the output port, and the transistors to place the transconductor circuit in a first or a second mode of operation. An input capacitance of the transconductor circuit operating in the first mode is larger than when the transconductor circuit is operating in the second mode. In the first mode, having a larger input capacitance results in a decreased flicker noise because the amount of flicker noise is inversely proportional to the input capacitance. In the second mode, having a smaller input capacitance leads to an increased flicker noise but that is acceptable for wide-bandwidth applications because wide-bandwidth signals may be less sensitive to flicker noise.

Abstract: Embodiments of the present disclosure relate to cellular technology applications of beamforming performed in the digital domain. In one aspect, an RF system for performing digital beamforming on a per-carrier basis is disclosed, where different phase and/or amplitude adjustments are applied to signals of different frequency ranges (i.e., to different carrier signals). In another aspect, an RF system for performing digital beamforming on a per-antenna basis is disclosed, where different phase and/or amplitude adjustments are applied to signals transmitted from or received by different antennas. In some embodiments, an RF system may be configured to implement both digital beamforming on a per-carrier basis and digital beamforming on a per-antenna basis. The RF systems disclosed herein allow implementing programmable beamforming in the digital domain in a manner that is significantly less complex than conventional implementations.

Abstract: Embodiments of the present disclosure relate to multi-band FDD transceivers. An example transceiver includes a LO, configured to generate a LO signal to be shared between a receiver and a transmitter of the transceiver. Both the receiver and the transmitter use quadrature signal processing and are configured to multi-band operation. Sharing a single LO to perform frequency conversion of different frequency bands of received and transmitted signals advantageously allows reducing the number of LOs used in a multi-band FDD transceiver.

Abstract: Embodiments of the present disclosure relate to cellular technology applications of beamforming performed in the digital domain. In one aspect, an RF system for performing digital beamforming on a per-carrier basis is disclosed, where different phase and/or amplitude adjustments are applied to signals of different frequency ranges (i.e., to different carrier signals). In another aspect, an RF system for performing digital beamforming on a per-antenna basis is disclosed, where different phase and/or amplitude adjustments are applied to signals transmitted from or received by different antennas. In some embodiments, an RF system may be configured to implement both digital beamforming on a per-carrier basis and digital beamforming on a per-antenna basis. The RF systems disclosed herein allow implementing programmable beamforming in the digital domain in a manner that is significantly less complex than conventional implementations.

Abstract: Embodiments of the present disclosure relate to multi-band FDD transceivers. An example transceiver includes a LO, configured to generate a LO signal to be shared between a receiver and a transmitter of the transceiver. Both the receiver and the transmitter use quadrature signal processing and are configured to multi-band operation. Sharing a single LO to perform frequency conversion of different frequency bands of received and transmitted signals advantageously allows reducing the number of LOs used in a multi-band FDD transceiver.

Abstract: A transmission module is provided that includes a transmitter, a loopback receiver, and a QEC controller. The QEC controller identifies quadrature imbalance in the transmitter based at least one a comparison of the data signals at the output of the loopback receiver with data signals at the input of the transmitter. Based on the comparison, the QEC controller can adjust one or more characteristics of the transmitter to correct quadrature errors in the transmitter.

Abstract: Embodiments of the present disclosure relate to multi-band FDD transceivers. An example transceiver includes a LO, configured to generate a LO signal to be shared between a receiver and a transmitter of the transceiver. Both the receiver and the transmitter use quadrature signal processing and are configured to multi-band operation. Sharing a single LO to perform frequency conversion of different frequency bands of received and transmitted signals advantageously allows reducing the number of LOs used in a multi-band FDD transceiver.

Abstract: Embodiments of the present invention may provide a receiver. The receiver may include an RF section, a local oscillation signal generator to generate quadrature local oscillation signals, and a quadrature mixture, coupled to the RF section, to downconvert a first group of wireless signals directly to baseband frequency quadrature signals and to downconvert a second group of wireless signals to intermediate frequency quadrature signals. The receiver may also include a pair of analog-to-digital converters (ADCs) to convert the downconverted quadrature signals to corresponding digital quadrature signals. Further, the receiver may include a digital section having two paths to perform signal processing on the digital baseband frequency quadrature signals and to downconvert the digital intermediate frequency signals to baseband cancelling a third order harmonic distortion therein.

Abstract: Apparatus and methods for analog-to-digital conversion of quadrature receive signals are provided herein. In certain implementations, a transceiver system includes at least a first pair of analog-to-digital converters (ADCs) associated with a first quadrature receiver channel and a second pair of ADCs associated with a second quadrature receiver channel. The first and second pairs of ADCs can provide analog-to-digital conversion of the same receive signal, but can have different noise profiles relative to one another, such as a low pass noise profile and a band pass noise profile. The transceiver system can further include a reconstruction filter for combining the outputs of at least the first and second pairs of ADCs to generate output signals associated with a lower overall noise profile relative to that of either pair of ADCs alone.

Abstract: Embodiments of the present invention may provide a receiver. The receiver may include an RF section, a local oscillation signal generator to generate quadrature local oscillation signals, and a quadrature mixture, coupled to the RF section, to downconvert a first group of wireless signals directly to baseband frequency quadrature signals and to downconvert a second group of wireless signals to intermediate frequency quadrature signals. The receiver may also include a pair of analog-to-digital converters (ADCs) to convert the downconverted quadrature signals to corresponding digital quadrature signals. Further, the receiver may include a digital section having two paths to perform signal processing on the digital baseband frequency quadrature signals and to downconvert the digital intermediate frequency signals to baseband cancelling a third order harmonic distortion therein.