Abstract: A N-path filter includes a plurality of switch-capacitor circuits controlled by a plurality of logical signals, respectively, and joined at a common shunt node, each of said switch-capacitor circuit comprising: a respective switch configured to controllably connect the common shunt node to a respective middle node in accordance with a respective logical signals among said plurality of logical signals; and a respective balanced MOS (metal oxide semiconductor) capacitor connected to the respective middle node, wherein the respective balanced MOS capacitor exhibits a capacitance at the respective middle node with reference to a power supply node and a ground node.

Abstract: A N-path filter includes a plurality of switch-capacitor circuits controlled by a plurality of logical signals, respectively, and joined at a common shunt node, each of said switch-capacitor circuit comprising: a respective switch configured to controllably connect the common shunt node to a respective middle node in accordance with a respective logical signals among said plurality of logical signals; and a respective balanced MOS (metal oxide semiconductor) capacitor connected to the respective middle node, wherein the respective balanced MOS capacitor exhibits a capacitance at the respective middle node with reference to a power supply node and a ground node.

Abstract: A radio transmitter includes a power amplifier configured to receive an input voltage signal and output an output voltage signal; a transformer configured to receive the output voltage signal and output a load voltage signal to a load; a sensing inductor configured to output a sensed current signal in accordance with a magnetic coupling with the transformer; a digitally controlled phase shifter configured to receive the output voltage signal and output a phase-shifted voltage signal in accordance with a phase control code; a mixer configured to output a mixed current signal in accordance with a mixing of the sensed current signal and the phase-shifted voltage signal; and a transimpedance amplifier with of a low-pass response configured to convert the mixed current signal into a mean voltage signal.

Abstract: A radio transmitter includes a power amplifier configured to receive an input voltage signal and output an output voltage signal; a transformer configured to receive the output voltage signal and output a load voltage signal to a load; a sensing inductor configured to output a sensed current signal in accordance with a magnetic coupling with the transformer; a digitally controlled phase shifter configured to receive the output voltage signal and output a phase-shifted voltage signal in accordance with a phase control code; a mixer configured to output a mixed current signal in accordance with a mixing of the sensed current signal and the phase-shifted voltage signal; and a transimpedance amplifier with of a low-pass response configured to convert the mixed current signal into a mean voltage signal.

Abstract: A RF (radio frequency) signal detector includes an I/Q (in-phase/quadrature) mixer configured to convert an amplified signal, received from a low-noise amplifier, into a baseband signal having an in-phase component and a quadrature component in accordance with a LO (local oscillator) signal; a local oscillator configured to output the LO signal; a pair of baseband filters configured to output a filtered signal comprising an in-phase component and a quadrature component; a pair of 3-level slicers configured to receive the filtered signal and output a sliced signal having an in-phase component and a quadrature component; a pair of data flip flops configured to sample the sliced signal into a decision including an in-phase component and a quadrature component in accordance with a sampling clock signal; and a digital signal processor configured to determine an existence and characteristic of a component of the RF signal around a frequency of the LO signal.

Abstract: The present disclosure provides a reconfigurable low noise amplifier (LNA) circuit. This reconfigurable LNA circuit can be used for connecting multiple receive signal paths to a particular LNA in one configuration as well as used for connecting a single receive signal path to a particular LNA in another configuration. In the single receive signal path configuration, the single receive signal path is not degraded by the parasitics of a particular set of switches used for the multiple receive signal paths configuration.

Abstract: An frequency down-converter includes a mixer configured to receive a RF (radio frequency) signal having a first end and a second end and output an intermediate signal comprising a first end and a second end in accordance with a LO (local oscillator) signal having a first end and a second end, wherein the first end and the second end of the LO signal jointly form a two-phase periodic signal of a fundamental frequency approximately equal to a mean frequency of a desired component of the RF signal.

Abstract: A wireless communication device includes a first low-noise amplifier (LNA). The wireless communication device also includes a first LNA load circuit coupled to an output of the LNA. The wireless communication device further includes a power splitter switchably coupled to the first LNA load circuit. The power splitter includes a negatively coupled transformer and is switchably coupled to multiple outputs.

Abstract: A low noise amplifier (LNA) reduces matching and switch noise. The LNA includes a main radio frequency signal path, an auxiliary radio frequency signal path and a phase shifter. The main path includes a first transistor and an inductor. The inductor is positioned between an input port of the LNA and the first transistor. The first transistor receives an input radio frequency signal via the inductor and provides a first amplified signal based on the input radio frequency signal. The auxiliary radio frequency signal path provides a second amplified signal for a noise cancellation mode based on the input radio frequency signal. The phase shifter applies a phase shift to an output signal of the LNA based on the first amplified signal and the second amplified signal.

Abstract: A low noise amplifier (LNA) reduces matching and switch noise. The LNA includes a main radio frequency signal path, an auxiliary radio frequency signal path and a phase shifter. The main path includes a first transistor and an inductor. The inductor is positioned between an input port of the LNA and the first transistor. The first transistor receives an input radio frequency signal via the inductor and provides a first amplified signal based on the input radio frequency signal. The auxiliary radio frequency signal path provides a second amplified signal for a noise cancellation mode based on the input radio frequency signal. The phase shifter applies a phase shift to an output signal of the LNA based on the first amplified signal and the second amplified signal.

Abstract: A wireless communication device includes a first low-noise amplifier (LNA). The wireless communication device also includes a first LNA load circuit coupled to an output of the LNA. The wireless communication device further includes a power splitter switchably coupled to the first LNA load circuit. The power splitter includes a negatively coupled transformer and is switchably coupled to multiple outputs.

Abstract: Certain aspects of the present disclosure provide methods and apparatus for generating multiple oscillating signals having different phases. One example multiphase generating circuit generally includes a first phase shifting circuit configured to phase shift an input signal having an input frequency, such that an output signal of the first phase shifting circuit has a first phase difference with respect to the input signal; a first frequency dividing circuit configured to receive the input signal and output a first set of signals having a first frequency less than the input frequency of the input signal; and a second frequency dividing circuit configured to receive the output signal of the first phase shifting circuit and output a second set of signals having a second frequency less than the input frequency of the input signal. The multiphase signals may be used for fast frequency estimation of the input signal or in N-path filters.

Abstract: Locking multiple VCOs to generate a plurality of LO frequencies, including: receiving a plurality of divided VCO feedback signals from a plurality of VCOs; receiving a reference signal multiplied by a predetermined number of the plurality of VCOs; generating and processing the predetermined number of phase differences between the multiplied reference signal and the plurality of divided VCO feedback signals in a single PLL circuit including a digital loop filter to receive and process the phase differences and generate (produce) a filter output, wherein the digital loop filter includes a plurality of delay cells equal to the predetermined number; and generating and outputting (delayed) control voltages for the plurality of VCOs based on the filter output.

Abstract: Locking multiple VCOs to generate a plurality of LO frequencies, including: receiving a plurality of divided VCO feedback signals from a plurality of VCOs; receiving a reference signal multiplied by a predetermined number of the plurality of VCOs; generating and processing the predetermined number of phase differences between the multiplied reference signal and the plurality of divided VCO feedback signals in a single PLL circuit including a digital loop filter to receive and process the phase differences and generate (produce) a filter output, wherein the digital loop filter includes a plurality of delay cells equal to the predetermined number; and generating and outputting (delayed) control voltages for the plurality of VCOs based on the filter output.