Analog Devices,inc.

Analog Devices Global

Analog Devices International Unlimited Company

Christopher W Angell

David J McLaurin

Christopher Mayer

Michael F Keaveney

Steven R Bal

Sudhir Desai

Justin L Fortier

Mostafa Haroun

Ionel Gheorghe

Xing Zhou

Oscar S Burbano

Systems, devices, and methods related to frequency converter arrangements are provided. For example, a frequency converter arrangement converts a first signal centered at a first frequency to a second signal centered at a second frequency different from the first frequency. The frequency converter arrangement includes local oscillator (LO) circuitry and in-phase, quadrature-phase (IQ) mixer circuitry coupled to the LO circuitry. The LO circuitry includes duty cycle correction circuitry to adjust a duty cycle of a pair of input clock signals. The duty cycle correction circuitry includes coarse tuning circuitry responsive to a digital calibration code, and analog tuning loop circuitry. The LO circuitry further includes quadrature divider circuitry coupled to an output of the duty cycle correction circuitry, where the quadrature divider circuitry generates an in-phase LO signal and a quadrature-phase LO signal from a pair of output clock signals at outputs of the duty cycle correction circuitry.

Analog tracking circuit to improve dynamic and static image rejection of a frequency converter

Apparatus and methods for phase synchronization of phase-locked loops (PLLs) are provided. In certain configurations, an RF communication system includes a PLL that generates one or more output clock signals and a phase synchronization circuit that synchronizes a phase of the PLL. The phase synchronization circuit includes a sampling circuit that generates samples by sampling the one or more output clock signals based on timing of a reference clock signal. Additionally, the phase synchronization circuit includes a phase difference calculation circuit that generates a phase difference signal based on the samples and a tracking digital phase signal representing the phase of the PLL. The phase synchronization circuit further includes a phase adjustment control circuit that provides a phase adjustment to the PLL based on the phase difference signal so as to synchronize the PLL.

Apparatus and methods for phase synchronization of phase-locked loops

Apparatus and methods for synchronizing phase-locked loops (PLLs) are provided. In certain implementations, a fractional-N synthesizer includes a PLL and a control circuit that controls a division value of the PLL. The control circuit includes an interpolator, a reset phase adjustment calculator, and a synchronization circuit. The interpolator can control a fractional portion of the PLL's division value. The reset phase adjustment calculator can include a counter for counting a number of cycles of the reference clock signal since initialization of the fractional-N synthesizer, and the reset phase adjustment calculator can generate a phase adjustment signal based on the count. The synchronization circuit can synchronize the PLL in response to a synchronization signal, and can correct for a synchronization phase error indicated by the phase adjustment signal.

Apparatus and methods for synchronizing phase-locked loops

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Cary, NC, United States of America

Christopher W Angell