Analog Devices,inc.

Analog Devices Global

Analog Devices International Unlimited Company

Analog Devices Global Unlimited Company

David J McLaurin

Christopher Mayer

Christopher W Angell

Antonio J Montalvo

Michael F Keaveney

Martin McCormick

Steven R Bal

Chris Angell

Sudhir Desai

Patrick Joseph Pratt

Trevor Clifford Caldwell

Kevin Glenn Gard

David Nelson Alldred

Zhao Li

Victor Kozlov

Manish J Manglani

Shipra Bhal

Peadar Antony Forbes

Justin L Fortier

Ionel Gheorghe

Mostafa Haroun

Oliver Gysel

Carl Grace

Zheng Gao

Hatice Dicle Ozis Unsal

Xing Zhou

Oscar S Burbano

Martin Steven McCORMICK

David Alldred

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 calibrating radio frequency transmitters to compensate for common mode local oscillator leakage are provided herein. In certain configurations herein, a transmitter generates a radio frequency transmit signal based on mixing a baseband input signal with a local oscillator signal. The transmitter is calibrated to compensate for common mode local oscillator leakage. Thus, a common mode component of the local oscillator signal is reduced or eliminated from the radio frequency transmit signal, which provides a number of benefits, including lower levels of undesired emissions from the transmitter.

Apparatus and methods for calibrating radio frequency transmitters to compensate for common mode local oscillator leakage

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

Transmitter noise cancellation may be applied on a channel by channel basis to active channels of an incoming radio frequency signal received at a receiver. A noise cancellation filter may be provided for each active channel in a predetermined signal band. Applying noise cancellation on a per active channel basis instead of to the entire receive band may substantially reduce the filtering requirement and number of filter coefficients or taps to save power and reduce manufacturing costs. Channelized transmitter noise cancellers, multi transmitter-receiver cross coupling cancellers, and hybrid full signal band and channelized transmitter noise cancellers are also provided.

Radio frequency transmitter noise cancellation

Apparatus and methods for transceiver calibration are provided. In certain configurations, a transceiver includes a transmit channel and an observation channel. The transmit channel includes a transmit mixer that up-converts a transmit signal by a first or transmit local oscillator frequency. The observation channel includes an observation mixer that down-converts an observed signal from the transmit channel by a second or observation local oscillator frequency that is offset from the first local oscillator frequency. By observing the transmit channel using a local oscillator frequency that is offset relative to the transmit channel's local oscillator frequency, the observation channel can observe transmit channel impairments substantially independently from observation channel impairments.

Apparatus and methods for transceiver calibration

A method and apparatus for phase adjustment of a RF transceiver is disclosed. Based on a first local oscillator signal and a second local oscillator signal, a beat signal that indicates the frequency and phase relationship between the first and second local oscillator signals can be generated. Using the beat signal, changing phase relationship between the first and second local oscillator signals can be cumulatively taken account for using phase averaging to allow quick restoration to observation of a previously observed channel.

Apparatus and methods for phase synchronization of local oscillators in a transceiver

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

A calibration system for an analog-to-digital converter (ADC) an internal ADC that receives an analog input and converts the analog input to digital multi-bit data. The calibration system also includes a reference shuffling circuit that shuffles reference values of comparators of the internal ADC. Further, the calibration system includes a calibration circuit that calibrates the comparators of the internal ADC. The calibration system includes a digital block that measures an amplitude based on the digital multi-bit data. Additionally, the calibration system includes calibration logic that controls the calibration circuit based on an output of the digital block.

System, method and recording medium for analog to digital converter calibration

Apparatus and methods are disclosed, such as those involving an RF receiver. One such apparatus includes a front end having an input and an output. The front end forms part of an RF signal receive path. The front end includes a front-end resistor configured to receive an input signal; and a passive mixer downstream of the front-end resistor on the receive path. The passive mixer mixes the input signal with a local oscillation signal. The front-end includes a transimpedance amplifier located downstream of the passive mixer on the receive path. The transimpedance amplifier includes an input and an output. The front end further includes a feedback resistor coupled between the input and output of the transimpedance amplifier. The gain of the front end is a ratio of the feedback resistance to the front-end resistance, and is temperature- and frequency-insensitive. The apparatus also provides relatively constant input impedance and high linearity.

Apparatus and method for radio frequency reception with temperature and frequency independent gain

Apparatus and methods are disclosed, such as those involving a low noise amplifier. One such apparatus includes a low noise amplifier circuit configured to receive a signal at an input node and to output an amplified signal at an output node. The low noise amplifier circuit includes a first transistor of a first polarity; and a second transistor of a second polarity complementary to the first polarity. The first and second transistors are connected in series between first and second supply voltage nodes via the output node. The circuit further includes a third transistor cascoded with one of the first transistor or the second transistor, but does not include a transistor cascoded with the other transistor. This configuration allows the low noise amplifier circuit to provide an increased high-frequency gain and linearity while having improved high-frequency system noise figure in, for example, deep submicron CMOS technology.

Apparatus and method for low noise amplification

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Raleigh, NC, United States of America

David J McLaurin