Systems and methods for power conversion are described. Symmetric topologies and modulation schemes are described that may reduce common-mode noise. For example, a system may include a transformer including a first secondary winding and a second secondary winding; a rectifier, including a set of switches, that connects taps of the first secondary winding and the second secondary winding to a first terminal and a second terminal, wherein the rectifier is symmetric with respect to the first secondary winding and the second secondary winding; a battery connected between the first terminal and the second terminal; and a processing apparatus that is configured to control the set of switches to rectify a multilevel voltage signal on the transformer, including: selecting a modulation scheme from among two or more modulation schemes based on a measured voltage level of the battery.

A distributed amplifier includes a transmission line configured so as to transmit a signal, a variable capacitor having one end connected to the transmission line and the other end connected to the ground, and configured so that the capacitance is adjustable, and a variable capacitor having one end connected to the transmission line and the other end connected to the ground, and configured so that the capacitance is adjustable. The transmission line is configured in such a manner that the inductance is adjustable.

A distributed amplifier includes a transmission line configured so as to transmit a signal, a variable capacitor having one end connected to the transmission line and the other end connected to the ground, and configured so that the capacitance is adjustable, and a variable capacitor having one end connected to the transmission line and the other end connected to the ground, and configured so that the capacitance is adjustable. The transmission line is configured in such a manner that the inductance is adjustable.

A radio-frequency modulator apparatus comprises a baseband stage, a mixer stage and a radio-frequency stage. The baseband stage comprises: an input line for receiving an input current representative of a baseband input signal, a baseband transistor that passes some or all of the input current between a first and a second terminal thereof, an electrical connection between the input line and a control terminal of the baseband transistor, and an output line connected to said control terminal. The mixer stage receives a signal from the baseband stage and mixes it with a radio-frequency local-oscillator signal to generate a radio-frequency mixed signal. The radio-frequency stage receives the radio-frequency mixed signal, applies the radio-frequency mixed signal to a control terminal of a radio-frequency transistor causing it to pass a radio-frequency output current between a first and a second terminal thereof, and outputs the radio-frequency output current as an output signal.

The disclosure relates to technology for an apparatus having a current conveyer comprising a first stage having a first differential input, and a second stage having a second differential input. The first and second stages are configured to operate in a push-pull mode to provide an output signal at a current conveyer output between the first stage and the second stage. The apparatus has a first frequency mixer configured to generate a first mixer signal based on an input signal and an oscillator signal having a first frequency. The first frequency mixer is configured to provide the first mixer signal to the first differential input. The apparatus has a second frequency mixer configured to generate a second mixer signal based on the input signal and a second oscillator signal having the first frequency. The second frequency mixer is configured to provide the second mixer signal to the second differential input.

A distributed amplifier includes: a transmission line having an input end that an input signal is input to; a transmission line having an output end that an output signal is output from; an input termination resistor connected to an end terminal of the transmission line; a plurality of unit cells arranged along the transmission lines, and having input terminals connected to the transmission line and output terminals connected to the transmission line; and a variable current source having one end connected to the end terminal of the transmission line and another end connected to a power supply voltage, and capable of adjusting a current amount between the transmission line and the power supply voltage.

A distributed amplifier includes: a transmission line having an input end that an input signal is input to; a transmission line having an output end that an output signal is output from; an input termination resistor connected to an end terminal of the transmission line; a plurality of unit cells arranged along the transmission lines, and having input terminals connected to the transmission line and output terminals connected to the transmission line; and a variable current source having one end connected to the end terminal of the transmission line and another end connected to a power supply voltage, and capable of adjusting a current amount between the transmission line and the power supply voltage.

A radio frequency (RF) transmission circuit includes an input stage, a current-mode mixer coupled to an output of the input stage, an attenuator coupled to an output of the current-mode mixer, and a matching network coupled to an output of the attenuator. The input stage, current-mode mixer, attenuator, and the matching network are configured in a series stack.

Disclosed is a frequency mixer. The frequency mixer includes a first matching circuit that generates a matched local oscillator (LO) signal based on an LO signal, a non-linear circuit that generates a non-linear LO signal based on the matched LO signal, a second matching circuit that generates a matched radio frequency (RF) signal based on an RF signal, a mixing circuit that generates a mixed signal based on a mixing of the non-linear LO signal and the matched RF signal, a third matching circuit that generates an intermediate frequency (IF) signal based on the mixed signal, wherein the non-linear circuit includes a non-linear transistor, a bias transistor, and an internal matching circuit connected in series.

A travelling wave mixer (TWM) is provided that includes an input artificial transmission line configured to transmit an input signal, an output artificial transmission line configured to transmit an output signal, a local oscillator (LO) artificial transmission line configured to transmit an LO signal, and a plurality of mixer stages connected in parallel between the output artificial transmission and the input artificial transmission line. Each of the mixer stages includes an input amplifier, a mixer and an output amplifier connected in series between the input artificial transmission line and the output artificial transmission line, where an input of the mixer receives an output of the input amplifier, and an output of the mixer is applied to an input of the output amplifier. Further, each of the mixer stages includes a phase-adjustable LO amplifier circuit connected between the LO artificial transmission line and an LO input of the mixer, where the phase-adjustable LO amplifier is configured to adjust an LO signal phase applied to the LO input of each mixer to null out a phase error in each mixer stage independently.