Analog Devices,inc.

Analog Devices International Unlimited Company

Reza Alavi

Saeed Aghtar

Jian Wang

Yong Wang

Esha John

Abdelaziz Chihoub

Haijiao Fan

Raju Hormis

Leo Montreuil

David J Mclaurin

Vladimir Friedman

Steven R Bal

Christoph M Steinbrecher

Jianxun Fan

Kenneth J Keyes

Kenneth J Keyes, Jr

Arathi Sundaresan

Shobhit Agrawal

Adam Ruan

Yupeng Liu

The present disclosure provides a method and a system to estimate LO leakage and quadrature error parameters for a transmitter RF front end, such as a direct up-conversion transmitter RF front end, in a joint fashion. The proposed method utilizes a PN sequence inserted at the transmitter baseband. At the observation receiver side, an RX accumulator is implemented to sum receiver signals to take advantage of a despreading gain using the same PN sequence from transmitter side. Through the despreading process, the receiver-transmitter channel may be estimated and used to extract the quadrature error parameters. The estimated channel may also be used to eliminate user data interference presented within the RX accumulator output, which may further be used to compute the LO leakage.

Determining LO leakage and quadrature error parameters of an RF front end

Apparatuses and methods related to digital mobile radio (DMR) with enhanced transceiver are disclosed herein. The transceiver detects waveforms of signals received by a digital mobile station radio (MS). By detecting whether the waveforms of the signals, the transceiver allows a digital baseband processor of the MS to remain in a sleep state while the signals are being detected by the DMR, thereby reducing an amount of power used while the signals are being detected.

Digital mobile radio with enhanced transceiver

A wideband RF tuner with blocker signal detector for detection of blocking signals and for fast recovery from noise limited region.

RF tuner with blocker detection and noise limited region recovery

A method and apparatus for estimating and compensating TX LO leakage using circuitry on a loopback path connecting the transmitter and receiver are provided. The TX LO leakage may be estimated by measuring the DC signal on the receiver, measuring the phase difference between the received LO signal and the receiver LO signal, and filtering LO harmonics that may arise from the use of non-linear mixers. The DC signal on the receiver may be measured by opening and closing the loopback path, or changing the gain of the loopback path, or flipping the phase of looped back TX signal. The method may be used in an initialization or tracking calibration scheme.

Transmitter LO leakage calibration scheme using loopback circuitry

A method of operating a radio frequency transceiver may include generating, by a transmit circuit of the transceiver, in-phase (I) and quadrature (Q) analog signals based on a digital calibration signal; mixing, by the transmit circuit, the I and Q analog signals with local oscillator (LO) and phase shifted LO signals to generate upconverted I and Q signals, the LO signal having a first frequency, and combining the upconverted I and Q signals to generate a combined signal; and converting, by a receive circuit of the transceiver, a signal based on the combined signal to a received digital signal using a sampling rate at a second frequency, the second frequency being less than the first frequency, wherein the converting downconverts frequency content in the combined signal.

Circuits and systems for transmitter calibration

Embodiments of the present invention may provide a signal processor with a wide gain range. The signal processor may comprise at least a discrete step gain stage and a continuous variable gain amplifier (VGA) stage. The discrete step gain stage may comprise a programmable gain amplifier (PGA) (e.g., low noise amplifiersand(LNAand LNA)). The VGA stage may provide a continuous range to compensate the LNAs gain steps. In one embodiment, the AGC controller enables an inherent hysteresis with the AGC step change if required.

RF AGC control

A method for delivering control information together with sampled data between a DSP and an RF/analog front-end in a high speed communication modem, which embeds sampled data and control information in frames to be transferred over one interface. A frame may comprise various fields, each may consist of one or more bytes or octets. The frame may have a data field for carrying the sampled data, and at least one control field for transferring the control information to update RF/analog front-end registers. The control field may include an octet containing a control address, an octet containing a control command, and an octet containing control data. The frame may also provide means of synchronization, e.g., by using a sync field to identify the frame boundary.

Method for transmitting sampled data and control information between a DSP and an RF/analog front-end

A method and system is provided for acquisition of the initial timing for a digital phase lock loop timing recovery system. A modified loop filter and post filter allows for an instantaneously change the oscillation frequency of a controllable oscillator and an instantaneous relative change of the sampling phase of the sampled data. These two features are used for initial timing recovery, in which the process of frequency and phase acquisition is separated into two independent steps. Once the initial timing is acquired, the timing recovery system is operated as a conventional digital phase lock loop timing recovery system to track additional frequency and phase drifts at the receiver with respect to the transmitter.

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Belle Mead, NJ, United States of America

Reza Alavi