Abstract:
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.
Abstract:
An adaptive predlstortlon system for controlling an open loop power amplifier includes a transmitter, a receiver, a phase and amplitude determination element configured to determine amplitude, and phase characteristics of an output signal generated In the transmitter, an amplitude resampling element to generate an updated AM-AM predlstortlon signal based on the output signal generated In the transmitter, and an amplitude predlstortlon element to compare the updated AM-AM predlstortlon signal with a factory-calibrated AM-A predlstortlon signal and generate an amplitude compensation signal. The adaptive predlslortlon system Includes a phase comparison element configured to compare the signal representing transmitter characteristics with a desired phase signal, a phase resampling lement configured to generate an updated AM-PM predlstortlon signal based on the output signal generated In the transmitter, and a has? predistortlon element configured to compare the updated AM-PM predlstortlon signal with a factory-calibrated AM-PM redlstortlon signal and generate a phase compensation signal.
Abstract:
A receiver for a multi-mode wireless device is provided. The receiver has multiple analog RF front end modules, with each module supporting a different mode of operation. The receiver has a single digital backend module for generating a digital baseband signal. A controller selects one of the available RF modules to use, and the selected RF module provides an analog communication signal to the digital backend. Each available mode has an associated set of factors. When a particular mode is selected, the set of factors associated with the selected mode is provided to the digital backend. The digital backend uses these factors to adjust the processing characteristics of its components, such as its analog to digital converter, filters, and gain controller. In this way, the single digital backend is adaptable to the requirements of each of the available radio modes.
Abstract:
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 sealer 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.
Abstract:
A mobile handset is arranged with an adaptive power controller to controllably adjust transmit power. The adaptive power controller is coupled to a power amplifier module to form a closed feedback loop. The adaptive power control module includes a first shifter, a first sealer, an accumulator and a hold element. The first shifter and first sealer receive respective bandwidth control signals and an error signal. The first shifter and first sealer generate a modified error signal that is forwarded to and filtered by the accumulator and the hold element to generate a power control signal. The power control signal, which is generated the radio frequency subsystem of the handset can quickly and accurately track rapid changes in transmit power.
Abstract:
A system and method for direct current offset correction are disclosed. One embodiment of the system includes a direct current offset correction circuitry (240a, 240b) having an adjustable bandwidth and control logic (119) configured to effect a bandwidth change of the direct current offset correction circuitry to speed up warm-up and settling time of the direct current offset correction circuitry.
Abstract:
A local oscillator circuit for generating a local frequency signal is provided. The local oscillator circuit may cooperate with a radio circuit for providing wireless reception or transmission. The radio circuit performs modulation or demodulation processes with reference to a defined carrier signal frequency. The local oscillator circuit has a voltage controlled oscillator that generates a VCO signal at frequency different than the carrier frequency. A frequency scaling circuit applies a scaling factor to the VCO signal, with the scaled signal generated at the frequency of the defined carrier frequency.
Abstract:
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.