Freescale Semiconductor,inc.

Motorola Corporation

Motorola Solutions, Inc.

Charles LeRoy Sobchak

Mahibur Rahman

Patrick Joseph Pratt

Manish N Shah

Sumit Anil Talwalkar

Louis Jay Vannatta

Qicai Shi

David Ryan Haub

Spyros Kyperountas

Leng H Ooi

James David Hughes

Neiyer S Correal

Emilio Quiroga

Lynn R Freytag

Clinton C Powell

A communication device includes a receiver that is capable of canceling in-channel interference. The receiver includes an antenna for receiving a wireless signal comprising in-channel components and an out-of-channel component, wherein the in-channel components comprise a desired component and an in-channel interference component. A first filter of the receiver filters the wireless signal by blocking at least a portion of the out-of-channel component to produce a first signal comprising the in-channel components, and at least a second filter of the receiver filters the wireless signal by blocking at least a portion of the in-channel components to produce a second signal comprising the out-of-channel component. An in-channel interference estimator of the receiver generates an in-channel interference estimation signal based on the second signal. And a combiner of the filter combines the first signal and the second signal to at least partially cancel the in-channel interference component of the first signal.

Method and apparatus for in-channel interference cancellation

An IPtuning circuit (and) for tuning the IPof a mixer (and) to minimize second order intermodulation distortion (IMD) in a receiver (and) of a transceiver (and). An operating characteristic of the mixer related to IMDis changeable by changing a value of a setting of the mixer. Two tones outside a bandpass of the receiver are injected into the mixer and a calibration tone within the bandpass is produced as a result of IMD. Alternatively, a DSSS signal is injected into the mixer and the calibration tone is produced at a chip rate of the DSSS signal. The power of the calibration tone is measured at a plurality of values of the settings. Alternatively, a four-level PN DSSS signal of known content is injected into the mixer, and a two-level PN DSSS signal of known content produced therefrom is correlated with a two-level PN DSSS signal of known content produced by a squaring circuit ().

Tuning a second order intercept point of a mixer in a receiver

A discrete time signal resampling circuit (). A data sample processing module () removes selected samples from a sequential plurality of discrete time signal samples to implement fractional resampling where the data sample processing module stores fewer samples than the number of samples between samples to be removed. A coefficient generator () in the resampling circuit generates a sequence of finite impulse response filter coefficients, with each coefficient in the sequence being associated with a respective distinct portion of a plurality of discrete time signal samples. A coefficient multiplier () multiplies each of the sequential plurality of finite impulse response filter coefficients by its associated respective distinct portion of the plurality of discrete time signal samples. An adder () produces a resampled output sample that consists of a sum of elements of the product vector produced by the coefficient multiplier.

Multirate resampling and filtering system and method

A radio frequency transceiver (), including a transmitter (), a duplexer () and a direct-conversion receiver () including a mixer (and). An IIP2 calibration system (), coupled to the transceiver, includes an IIP2 coefficient estimator () for calculating an estimate of second-order distortion intermodulation distortion, and an IIP2 controller () for adjusting an IIP2 tuning port of the mixer in the receiver to minimize second-order distortion intermodulation distortion in the receiver that may be caused by the receiver receiving a transmit RF signal leaking through the duplexer.

Adaptive IIP2 calibration

An automatic gain control (AGC) system for a receiver and corresponding method facilitate AGC in a receiver. The automatic gain control system includes an on-channel signal detectorconfigured to provide an on-channel signal level indication corresponding to a narrow band on-channel signal and a wideband signal detectorconfigured to provide a wideband signal level indication corresponding to a wideband signal, where the wideband signal includes the narrow band on-channel signal. Further included is a controllerthat is coupled to the wideband signal level indication and the on-channel signal level indication and that is configured to provide a gain control signal corresponding to the wideband signal level and one or more of a plurality of states of the receiver.

AGC for narrowband receivers

A radio frequency receiver () includes at least one amplifier (and) for amplifying a signal received by the radio frequency receiver, an automatic gain control system () for controlling a gain of the at least one amplifier, and a direct current offset correction filter () for reducing any direct current component of the signal amplified by the at least one amplifier. The direct current offset correction filter has a bandwidth that is dynamically controlled by a change in the gain of the at least one amplifier. The radio frequency receiver also includes a digital automatic gain control unit () having a bandwidth that is dynamically controlled by the change in the gain of the at least one amplifier.

Radio frequency receiver having dynamic bandwidth control and method of operation

A method and apparatus are provided for providing improved radio frequency (RF) receiver signal correction. For RF receiver circuitry () having receive path and a warmup period associated therewith and including at least one analog baseband gain control stage () having a gain associated therewith, the method includes the step of performing a DC correction calculation operation during the warmup period to derive a DC correction value having a first component and a second component for each of the at least one gain control stage (). The DC correction calculation step includes the steps of performing a first closed loop correction () of a baseband path to derive the first component of the DC correction value and performing a second closed loop correction () of the receive path as a function of the () gain during the warmup period to derive the second component of the DC correction value. During operation after the warmup period (), an open loop correction is performed for instantaneous DC correction as function of the PMA () gain and the DC correction value.

DC offset correction system for a receiver with baseband gain control

A multirate processing circuit () with a resampling filter () to accept a sampled input signal () sampled with a first clock rate and to filter the sampled input signal to remove spectral components above a spectral bandwidth of a second clock rate. The sampled input signal represents a signal that is more efficiently processed at the second clock rate, which is fractionally related to the first clock rate. The multirate processing circuit () also has a discrete time processor () that receives the resampling filter output () and processes that output at an integer power of two multiple of the first clock rate. The discrete time processor () further excludes selected samples from the processing so as to effectively perform discrete time processing of the resampling filter output () at the integer power of two multiple of the second clock rate.

Fractionally related multirate signal processor and method

At least one adjustable gain analog amplifier (and) in an analog line-up () amplifies by a gain an analog signal at an input of the analog line-up (). The at least one adjustable gain analog amplifier (and) is operable at one or more gains. At least one digital estimation device (and) receives signal via an output () of the analog line-up () and provides a digital signal estimate representative of an analog signal at an input of a respective one of the at least one adjustable gain analog amplifier (and) in the analog line-up (). An AGC controller () monitors the digital signal estimate. The AGC controller () adjusts the gain of the at least one analog amplifier (and). An RF receiver and an integrated circuit utilizing the novel features are also disclosed.

Automatic gain control using multiple equalized estimates dynamic hysteresis

Methods () and corresponding systems () for determining and correcting a DC offset in a receiver operate to sample () a signal to provide complex samples; estimate () a Direct Current (DC) offset corresponding to each of the complex samples, the estimating the DC offset further including solving a plurality of equations relating to the plurality of complex samples, e.g., N simultaneous equations in N samples with a power of the signal invariant across the N samples, to deterministically derive offset values; and then remove () the DC offset from the signal.

DC offset correction for constant envelope signals

A direct current (DC) offset correction system for a direct conversion receiver and corresponding receiver and methods facilitate reduction of DC offsets in such receivers. One method includes calibrating a DC offset correction system in a closed loop configuration over each of a plurality of gain settings to provide a plurality of offset data for an operating mode of the direct conversion receiver; selecting one of the plurality of offset data based on a current gain setting of the direct conversion receiver as supplied, e.g., by an AGC system; and operating the DC offset correction system in an open loop configuration using the one of the plurality of offset data to correct for a DC offset in the direct conversion receiver.

DC offset correction for direct conversion receivers

Dynamic gain and phase compensation is provided in a radio frequency (RF) receiver () including at least one switched Low Noise Amplifier (LNA) () coupled to an RF gain control unit () providing a gain control signal to the at least one switched LNA () for control thereof. The RF receiver also includes an analog-to-digital (A/D) converter () for digitizing the RF signal and outputting an N-bit digital signal to the RF gain control unit (). The method for gain compensation includes dynamically adjusting the N-bit digital signal to compensate for the at least one switched LNA () in response to the gain control signal. The method for phase compensation includes dynamically normalizing the N-bit digital signal into an M-bit signal range to derive an M-bit digital signal, where M&#x2266;N and dynamically phase adjusting the M-bit digital signal to compensate for the at least one switched LNA () in response to the gain control signal.

Method and apparatus for dynamic gain and phase compensations

A generator () generates first and second training signals () that originate within a wireless communication device (FIG.) instead of being received from a source outside the device. A receive portion () of the device processes the first training signal to derive a processed training signal. An adaptive equalizer () equalizes the processed training signal to derive an equalized training signal. A processor () compares the equalized training signal and the second training signal using an adaptive algorithm to derive coefficients for the adaptive equalizer to compensate for variations in the receive portion, and adjusts the adaptive equalizer in accordance with the coefficients to derive a compensated output signal.

Method and apparatus for compensating for variations in a receive portion of a wireless communication device

A narrowband interference cancellation system, method and digital signal processor is disclosed that removes narrowband interference in wide band communication systems. The system includes a narrowband processing component, wideband processing component, soft metric generator and at least one filter. The system is configured to receive a signal, identify one or more narrowband interferers in the received signal and filter out identified narrowband interferers. The narrowband processing component includes a filter bank configured to separate the received signal into a predetermined number of channel bands and identify a band with interference. The wide band processing component provides an average level for an unfiltered version of the received signal. The soft decision metric generator produces metrics based on predetermined thresholds. The filters receive coefficients that are determined using outputs from the soft decision metric generator that are first averaged using long term integrators and then stored in lookup tables.

Growing community of inventors

Davie, FL, United States of America

Charles LeRoy Sobchak