Patent application number | Description | Published |
20080232268 | LMS Adaptive Filter for Digital Cancellation of Second Order Inter-Modulation Due to Transmitter Leakage - A transmit signal second-order inter-modulation (IM | 09-25-2008 |
20100067622 | Circuit, Controller and Methods for Dynamic Estimation and Cancellation of Phase and Gain Imbalances in Quadrature Signal Paths of a Receiver - A controller and a circuit work together to enable a selective and dynamic adjustment to correct phase and gain imbalances in quadrature signal paths of a receiver. Under select conditions, it has been determined that statistical estimates of gain and phase imbalance can be applied to adjust signals in the quadrature signal paths of a receiver. The controller validates the select conditions before updating the estimate of the gain imbalance and the estimate of the phase imbalance. The controller directs a compensator under select operating conditions such that validated dynamic estimates of the gain and phase imbalance or calibration data is applied to the quadrature signal paths. The controller disables the compensator and enables an estimator and a calculator when estimates are unavailable for the present operating conditions. | 03-18-2010 |
20100172450 | Circuits, Systems, and Methods for Managing Automatic Gain Control in Quadrature Signal Paths of a Receiver - A system provides closed-loop gain control in a WCDMA mode and open loop control in an EDGE/GSM mode. Gain control is distributed across analog devices and a digital scaler in a wireless receiver. In the WCDMA mode, a loop filter generates an error signal that is forwarded to analog and digital control paths. The analog control path includes a first adder, a programmable hysteresis element, and a lookup table. The analog control signal is responsive to thresholds, which when used in conjunction with a previous gain value determine a new gain value. The digital control path includes a second adder, a programmable delay element, and a converter. A control word is responsive to a difference of the error signal, a calibration value, and the analog control signal. Blocker detection is provided in the WCDMA mode of operation. A controller sets system parameters using a state machine. | 07-08-2010 |
20110116403 | LMS Adaptive Filter for Digital Cancellation of Second Order Inter-Modulation Due to Transmitter Leakage - A transmit signal second-order inter-modulation (IM2) canceller for a portable handset using a full duplex mode of operation (e.g., WCDMA) is used to controllably reduce IM2 introduced by a transmit signal that appears in a received signal in a receive channel of the portable handset. The transmit signal IM2 canceller includes a delay estimator and a digital signal adjuster. The delay estimator receives a first input from a receive channel and a second input from a transmit channel. The delay estimator generates an estimate of the IM2 that the transmit channel introduces in the receive channel. The digital signal adjuster removes the estimate of the IM2 before forwarding a modified receive channel signal to a baseband subsystem of the portable handset. | 05-19-2011 |
20120134402 | CIRCUITS, SYSTEMS, AND METHODS FOR MANAGING AUTOMATIC GAIN CONTROL IN QUADRATURE SIGNAL PATHS OF A RECEIVER - A system provides closed-loop gain control in a WCDMA mode and open loop control in an EDGE/GSM mode. Gain control is distributed across analog devices and a digital scaler in a wireless receiver. In the WCDMA mode, a loop filter generates an error signal that is forwarded to analog and digital control paths. The analog control path includes a first adder, a programmable hysteresis element, and a lookup table. The analog control signal is responsive to thresholds, which when used in conjunction with a previous gain value determine a new gain value. The digital control path includes a second adder, a programmable delay element, and a converter. A control word is responsive to a difference of the error signal, a calibration value, and the analog control signal. Blocker detection is provided in the WCDMA mode of operation. A controller sets system parameters using a state machine. | 05-31-2012 |
20120170624 | SYSTEMS AND METHODS FOR POWER CONTROL IN A MULTIPLE STANDARD MOBILE TRANSMITTER - A transmitter adjusts a transmitted power level by modifying a control input of a variable gain amplifier. A power amplifier control system includes an envelope extractor, an error extractor, and a feed-forward multiplier. The envelope extractor receives data signal inputs and computes the envelope of the combined signal. The error extractor generates an error signal as a function of the combined signal and the output power generated by the power amplifier. The feed-forward multiplier generates a modified error signal that is responsive to a function of the gain in a feedback path. A corresponding method for controlling a power level is also disclosed. In some embodiments, a transmit chain with a power control loop is used to adjust the transmit signal power applied at an input of a variable gain amplifier. A corresponding method for adjusting the transmit signal power level is also included. | 07-05-2012 |
20120183106 | CIRCUIT, CONTROLLER AND METHODS FOR DYNAMIC ESTIMATION AND CANCELLATION OF PHASE AND GAIN IMBALANCES IN QUARDRATURE SIGNAL PATHS OF A RECEIVER - A controller and a circuit work together to enable a selective and dynamic adjustment to correct phase and gain imbalances in quadrature signal paths of a receiver. Under select conditions, it has been determined that statistical estimates of gain and phase imbalance can be applied to adjust signals in the quadrature signal paths of a receiver. The controller validates the select conditions before updating the estimate of the gain imbalance and the estimate of the phase imbalance. The controller directs a compensator under select operating conditions such that validated dynamic estimates of the gain and phase imbalance or calibration data is applied to the quadrature signal paths. The controller disables the compensator and enables an estimator and a calculator when estimates are unavailable for the present operating conditions. | 07-19-2012 |
20140086370 | CIRCUITS, SYSTEMS, AND METHODS FOR MANAGING AUTOMATIC GAIN CONTROL IN QUADRATURE SIGNAL PATHS OF A RECEIVER - A system provides closed-loop gain control in a WCDMA mode and open loop control in an EDGE/GSM mode. Gain control is distributed across analog devices and a digital scaler in a wireless receiver. In the WCDMA mode, a loop filter generates an error signal that is forwarded to analog and digital control paths. The analog control path includes a first adder, a programmable hysteresis element, and a lookup table. The analog control signal is responsive to thresholds, which when used in conjunction with a previous gain value determine a new gain value. The digital control path includes a second adder, a programmable delay element, and a converter. A control word is responsive to a difference of the error signal, a calibration value, and the analog control signal. Blocker detection is provided in the WCDMA mode of operation. A controller sets system parameters using a state machine. | 03-27-2014 |
20150023450 | APPARATUS AND METHODS FOR POWER CONTROL IN MOBILE COMMUNICATION DEVICES - Apparatus and methods for power control in mobile communication devices are provided. In one aspect, a method for accurately controlling an adjustable power level of a data signal in a transmit chain of a transmitter is provided. The method includes adjusting a controllable gain level of a digital-to-analog converter based on a desired peak-to-average ratio of a transmit signal envelope, adjusting a digitally controlled discrete gain-step amplifier, the amount of gain per step based on an initial estimate of the transmitter gain and a target power, applying a factor to a gain adjuster responsive to the gain step change in the transmit chain, and repeating the adjusting and applying steps until a feedback signal level exceeds a reference signal level. | 01-22-2015 |