Ericsson Gmbh

Telefonaktiebolaget Lm Ericsson (publ)

Ronald D Boesch

Domenico Arpaia

Jeffrey A Schlang

William O Camp, Jr

Charles Gore

Ronald C Meadows

Havish Koorapaty

Leland Scott Bloebaum

John W Northcutt

Rodney A Dolman

Christopher R Koszarsky

Peter J Doherty

Thomas E Medl

Kevin P Conroy

A power controller for a mobile terminal variable gain amplifier (VGA). A controller consistent with the invention controls VGA output using a feedback error signal established based on the difference between a signal representative of the VGA output and a signal representative of a target output. The error signal causes convergence of the VGA output to the target output based on a magnitude of the difference. A method of controlling the output of a variable gain amplifier in a mobile terminal is also provided.

Power controller for a mobile terminal

An RF full-duplex communication device operates in a selected range of channels spaced by a selected increment. A transmitter and a receiver are connected to a duplex filter for simultaneously transmitting and receiving signals. A low frequency offset channel stepper is adapted to selectively shift frequency either the designated duplex spacing or offset therefrom. A high frequency channel stepper is connected to the transmitter and selectively connected to the receiver either directly or through the low frequency offset channel stepper, where the high frequency channel stepper is adapted to selectively shift frequency in steps substantially equal to the selected increment. A controller is adapted to (a) selectively connect the high frequency channel stepper directly to the receiver when the device is in a camping mode not transmitting a signal, (b) selectively connect the high frequency channel stepper to the receiver through the low frequency offset channel stepper and cause the low frequency offset channel stepper to shift frequency the normal duplex spacing when the device is in a normal communicating mode, and (c) selectively connect the high frequency channel stepper to the receiver through the low frequency offset channel stepper and cause the low frequency offset channel stepper to shift frequency on the incrementally spaced grid when the device is in a slotted communicating mode. The controller controls a switch for connecting or disconnecting the low frequency offset channel stepper from the receiver.

Frequency generation for CDMA terminal with slotted receive mode

A narrow bandwidth signal, such as a narrowband FM signal, is modulated in a modulator that modulates a wide bandwidth signal, such as a CDMA signal, by oversampling the narrow bandwidth signal and applying the oversampled narrow bandwidth signal to the modulator. By oversampling the narrow bandwidth signal, the same fixed low pass filter can be used for both the wide bandwidth signal and the oversampled narrow bandwidth signal. Accordingly, different low pass filters or switched low pass filters are not needed. The DC offset that is introduced by the digital-to-analog converter and/or the low pass filter of the modulator is compensated, preferably in the digital domain, to thereby reduce DC offset within acceptable limits for the modulation that is being used. More preferably, compensation is provided by subtracting from the sampled signal, a digital value representing the DC offset in the filtered analog signal that is introduced by the digital-to-analog converter and/or the low pass filter. A sensor senses the DC offset in the filtered analog signal. An analog-to-digital converter is responsive to the sensor to convert the sensed DC offset into a digital offset signal. A subtractor is responsive to the analog-to-digital converter to subtract the digital DC offset signal from the sampled signal and to apply the sampled signal minus the DC offset signal, to the digital-to-analog converter.

Dual-mode modulation systems and methods including oversampling of narrow bandwidth signals and DC offset compensation

A mobile terminal uses stored GPS data to expedite position determination when placing emergency calls. The mobile terminal receives supporting GPS data such as almanac and ephemeris information from a supporting digital wireless network when digital service is available. When operating in an analog service area where GPS data is not available from the analog wireless network, the mobile terminal uses GPS data previously received in a digital service area, unless that data is too old to be useful. Additionally, the mobile terminal can periodically update its stored GPS data while in standby in an analog service area, based on receiving the needed data directly from available GPS satellites. The mobile terminal or digital wireless network may automatically update GPS data stored in the mobile terminal based on the age of stored data, or based on the probability of moving into an analog service area.

Expedited location determination in analog service areas

Power control circuitry for the transmitting section of a mobile terminal provides gain control for amplifiers operating at different frequencies. Preferably, one amplifier controls the signal gain the signal transmission path in the IF section and another amplifier controls gain in the signal transmission path in the radio frequency (RF) section. One variable gain amplifier may be controlled based on the strength of the received signals while the other may be controlled based on commands from the base station and/or calibration and alignment settings during manufacturing. In addition, one or both of the amplifiers may optionally be controlled in whole or in part based on calibration and/or alignment settings established during manufacturing. Preferably, the gain control signal based on received signal strength is analog based and the control signal received from the control system is a pure digital signal substantially immune to noise. In such an embodiment, the corresponding amplifier is configured to receive a digital value and provide a corresponding amplifier gain.

Power control for wireless communications system

A power amplifier circuit has a driver amplifier stage including a low band driver amplifier and a high band driver amplifier. A final amplifier stage includes a linear mode amplifier for amplifying digitally modulated signals and a saturated (nonlinear) mode amplifier for amplifying frequency modulated (analog) signals. A switching network interconnects the driver amplifier stage and the final amplifier stage. Depending on the desired mode of operation, an appropriate driver amplifier can be coupled to an appropriate final amplifier to most effectively and efficiently amplify analog or digital RF signals in either of a plurality of frequency bands. A diplex matching circuit is coupled to the linear mode final amplifier for impedance matching and for separating D-AMPS (800 MHz band) and PCS (1900 MHz band) digital signals. A power impedance matching circuit is coupled to the output of the saturated mode final amplifier.

Dual-band, dual-mode power amplifier

During production, a wireless communications device manufacturer determines the version of specific integrated circuits being used by interpreting the response signals generated by the integrated circuits in response to an electronic query. The device manufacturer preferably establishes a cross reference list of response signals and computer chip versions for the affected computer chip type. Each integrated circuit chip manufacturer then designs and manufactures their respective integrated circuit chips to generate their corresponding response signal when a particular predetermined query is received by the chip. During subsequent device production, a factory system is connected to the device and sends the query signal. The computer chip detects this query and, in response, the integrated circuit generates the pre-defined response signal. The factory system compares this generated response signal to the cross-reference list of assigned response signals to determine the integrated circuit version being used. The factory system then selects the appropriate factory settings based on the integrated circuit version identified and loads those factory settings into the wireless communications device. In addition, the factory system may optionally send an activation code to the integrated circuit chip based on the version of integrated circuit chip identified to enable the additional function available on that version of integrated circuit chip.

Manufacturing method for wireless communications devices employing potentially different versions of integrated circuits

An RF amplifier includes a phase modulator developing a phase modulated RF input signal to be transmitted. A power amplifier receives the RF input signal and amplifies the RF input signal to develop an RF output signal. An amplifier control is operatively associated with the phase modulator and the power amplifier. The amplifier control includes a memory for storing correction information correlating desired amplitude of the RF output signal relative to actual amplifier amplitude, and a control varies power amplifier supply voltage responsive to the correction information to linearize amplitude modulation in the power amplifier.

Circuit and method for I/Q modulation with independent, high efficiency amplitude modulation

An RF amplifier includes an oscillator developing an RF input signal to be transmitted. A power amplifier receives the RF input signal and amplifies the RF input signal to develop an RF output signal. An amplifier control is operatively associated with the oscillator and the power amplifier. The amplifier control includes means for developing a control signal representing a desired amplitude of the RF output signal. A memory stores correction information correlating actual amplitude of the RF output signal relative to the control signal, and a control varies the power amplifier circuit supply voltage using the control signal modified responsive to the correction information for the desired amplitude.

Circuit and method for linearizing amplitude modulation in a power amplifier

A power amplifier circuit has a driver amplifier stage including a low band driver amplifier and a high band driver amplifier. A final amplifier stage includes a linear mode amplifier for amplifying digitally modulated signals and a saturated (nonlinear) mode amplifier for amplifying frequency modulated (analog) signals. A switching network interconnects the driver amplifier stage and the final amplifier stage. Depending on the desired mode of operation, an appropriate driver amplifier can be coupled to an appropriate final amplifier to most effectively and efficiently amplify analog or digital RF signals in either of a plurality of frequency bands. A matching circuit is coupled to the linear mode final amplifier for impedance matching and for separating D-AMPS (800 MHz band) and PCS (1900 MHz band) digital signals. A power impedance matching circuit is coupled to the output of the saturated mode final amplifier. In one embodiment, an isolator is coupled to the output of one or more of the low band or high band outputs of the duplex matching circuit. In the low band analog path, a duplexer is provided ahead of the coupling means for reducing the RF power requirements on the coupling means. The switching network and input filter stage may precede a driver amplifier stage.

Dual-band, dual-mode power amplifier with reduced power loss

When attempting to reduce the number of battery cells in cellular telephones, a frequency synthesizer or phase locked loop located within the cellular telephone will output an increasing amount of noise. In order to reduce the amount of noise output when reducing the number of battery cells in such systems, the present invention employs a voltage step up device which effectively increases the voltage range of a voltage controlled oscillator within the frequency synthesizer. To further reduce the noise, the voltage step-up unit is employed with passive elements thus reducing the noise further and optimizing the output of the phase locked loop. Several different designs are discussed to further reduce space requirements and increase programmability of the system.

Voltage step up for a low voltage frequency synthesizer architecture

A narrow bandwidth signal, such as a narrowband FM signal, is modulated in a modulator that modulates a wide bandwidth signal, such as a CDMA signal, by oversampling the narrow bandwidth signal and applying the oversampled narrow bandwidth signal to the modulator. By oversampling the narrow bandwidth signal, the same fixed low pass filter can be used for both the wide bandwidth signal and the oversampled narrow bandwidth signal. Accordingly, different low pass filters or switched low pass filters are not needed.

Dual-mode modulation systems and methods including oversampling of

A mobile radio telephone having a minimized tuning bandwidth, based on limiting intermediate frequencies at the highest and lowest expected receive frequencies in each band. A dual band, dual mode mobile phone can be constructed which maintains or improves intermodulation performance using fewer battery cells without additional circuitry.

Tuning bandwidth minimization for low voltage dual band receiver

Modulation systems and methods compensate for the DC offset that is introduced by the digital-to-analog converter and/or the low pass filter thereof. Compensation is preferably provided in the digital domain, to thereby reduce DC offset within acceptable limits for the modulation that is being used. More preferably, compensation is provided by subtracting from the digital input signal, a digital value representing the DC offset in the filtered analog signal that is introduced by the digital-to-analog converter and/or the low pass filter. A sensor senses the DC offset in the filtered analog signal. An analog-to-digital converter is responsive to the sensor to convert the sensed DC offset into a digital offset signal. A subtractor is responsive to the analog-to-digital converter to subtract the digital DC offset signal from the digital input signal and to apply the digital input signal minus the DC offset signal, to the digital-to-analog converter.

Modulation systems and methods that compensate for DC offset introduced

An amplifier circuit in a wireless telecommunications device includes a digital-to-analog converter (DAC) and a mirror circuit to deliver variable current levels to transmission circuitry. The DAC receives a digital signal indicating the desired current strength under the particular device circumstances and requirements, and an analog signal corresponding thereto is forwarded to the mirror circuit, which amplifies the analog signal to the desired level for driving the transmission circuitry.

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Morrisville, NC, United States of America

Ronald D Boesch