A harmonic-rejection mixer apparatus includes a mixing circuit and a combining circuit. The mixing circuit receives mixes an input signal and a first local oscillator (LO) signal to generate a first output signal, and mixes the same input signal and a second LO signal to generate a second output signal, wherein the first LO signal and the second LO signal have a same frequency but different phases. The combining circuit combines the first output signal and the second output signal, wherein harmonic rejection is at least achieved by combination of the first output signal and the second output signal.

This application relates to a sideband suppression method performed at a computer device. The method includes: obtaining a target baseband signal, a target signal correlated parameter corresponding to the target baseband signal, the target signal correlated parameter including at least one of a signal feature parameter corresponding to the target baseband signal or a signal feature parameter of a carrier signal corresponding to the target baseband signal, and a corresponding target sideband suppression parameter according to the target signal correlated parameter; performing signal correction on the target baseband signal based on the target sideband suppression parameter, to obtain a target corrected baseband signal, the target sideband suppression parameter being used for suppressing a power of a first suppression sideband corresponding to the target baseband signal; and inputting the target corrected baseband signal to a modulator for signal modulation, to obtain a target modulation signal corresponding to the target baseband signal.

A system includes: a baseband phase generator configured to receive differential in-phase (I) and quadrature (Q) signals and configured to output N phase-shifted baseband signals, wherein N is greater than 4, further wherein the baseband phase generator comprises a plurality of notch filters configured to receive the I and Q signals; and an upconverter configured to receive the phase-shifted baseband signals, to perform mixing on the phase-shifted baseband signals, and to output a differential upconverted signal.

Embodiments of a mixer of a Near field communication (NFC) receiver device and a method for operating a mixer of an NFC receiver device are disclosed. In an embodiment, a mixer of an NFC receiver device includes an input unit from which an input signal is received, a sample and hold circuit configured to sample the input signal and to store electrical charge based on the sampled input signal in order to generate a differential output signal, a control unit configured to switch the sample and hold circuit between different operational modes based on whether the input signal is a single-ended input signal or a differential input signal, and a differential output unit from which the differential output signal is output. Other embodiments are also described.

Transmit and/or receive beamforming signal generation includes a voltage-controlled oscillator (VCO) for generating a lower or higher master frequency output signal in accordance with a selection of a lower or higher frequency carrier frequency. A local oscillator generates local oscillator signals in quadrature in response to the maser frequency output signal. One or more mixer stages generate sidebands in response to a received information signal and the local oscillator signals in quadrature. The one or more mixer stages generate an output information signal in response to high-side injection of lower sidebands of the developed sidebands when the lower frequency carrier frequency is selected, and generate the output information signal in response to low-side injection of higher sidebands of the developed sidebands when the higher frequency carrier frequency is selected. Multi-band operation of transmit and receive arrays can be performed.

Embodiments of a mixer of a Near field communication (NFC) receiver device and a method for operating a mixer of an NFC receiver device are disclosed. In an embodiment, a mixer of an NFC receiver device includes an input unit from which an input signal is received, a sample and hold circuit configured to sample the input signal and to store electrical charge based on the sampled input signal in order to generate a differential output signal, a control unit configured to switch the sample and hold circuit between different operational modes based on whether the input signal is a single-ended input signal or a differential input signal, and a differential output unit from which the differential output signal is output. Other embodiments are also described.

A digital quadrature modulator holds local oscillator circuitry configured to provide local oscillator signals, and local oscillator polarity logic circuitry configured to select an In-phase and a Quadrature local oscillator signal according to a sign bit of an In-phase control word and a sign bit of a Quadrature control word, respectively. The modulator holds a number of local oscillator control logic circuits, each configured to generate a conditioned signal by gating one or both of the selected local oscillator signals according to values of the In-phase control word and/or values of the Quadrature control word. The modulator has one or more sets of switched-capacitor units, where each unit has an output provided by an output capacitor, and where a signal at the input side of the output capacitor is controlled by a conditioned signal. The outputs of at least two of the switched-capacitor units are combined in a common node.

An apparatus and method. The method includes filtering an output of an in-phase (I-mixer); filtering an output of a quadrature-mixer (Q-mixer); converting an output of a first low pass filter (LPF); converting an output of a second LPF; buffering an output of a first analog-to-digital converter (ADC); buffering an output of a second ADC; buffering a transmitter signal; generating a reference signal from an output of a transmitter (TX) data capture buffer; removing DC from the reference signal; and adaptively tuning an I-mixer digital-to-analog (DAC) code and a Q-mixer DAC code from an output of a first receiver (RX) data capture buffer, an output of a second RX data capture buffer, an output of a DC removal unit, and a predetermined step size for each of the I-mixer DAC code and the Q-mixer DAC code.

Embodiments disclosed herein relate to quadrature signal generation, and more particularly, to wideband differential quadrature signal generation at millimeter-wave frequencies using over-coupled directional couplers. In an example, a quadrature signal generation sub-circuit includes two conductive strips arranged in parallel with respect to each other on different layers of a metal interconnect of a substrate (i.e., during a complementary metal-oxide semiconductor (CMOS) fabrication process) that form a directional coupler. Each conductive strip has a length and a width configured such that an input end of the first conductive strip and a coupled end of the second conductive strip, that are electromagnetically coupled together, produce an over-coupling factor. The input end may be configured to couple to a local oscillator, and the coupled end may be configured to couple to a mixer. The directional coupler may provide, to the mixer, an output of a desired bandwidth based on the over-coupling factor.