Ericsson Gmbh

Texas Instruments Corporation

Charles Gore

Jeffrey A Schlang

William O Camp, Jr

Domenico Arpaia

Paul Wilkinson Dent

Abdellatif Bellaouar

Ronald D Boesch

Rodney A Dolman

Jeff D Laster

Aristotle Hadjichristos

Ron Boesch

Jacob Mannerstrale

A wireless communication device (UST), comprising an input for receiving baseband data (I, Q) in a first signal having a first frequency. The device also comprises circuitry () for increasing the first frequency, to form a second signal having a second frequency, in response to a first frequency reference signal (IF), and the device comprises circuitry () for increasing the second frequency, to form a third signal having a third frequency, in response to a second frequency reference signal (LO). Lastly, the device comprises an antenna (ATU) for transmitting the baseband data at a final transmission frequency selected as a band within a predetermined set of frequency bands. With reference to the preceding, the first frequency reference signal and the second frequency reference signal are variable and are selected in response to the final transmission frequency which is a particular band selected as a different band at different times and from the predetermined set of frequency bands.

Wireless communication system with variable intermediate frequency transmitter

Multiple-mode direct phase/amplitude modulation circuitry () for use in a transceiver () of a device such as a wireless handset () is disclosed. The modulation circuitry () includes a modulation loop () for modulating a phase signal into a Gaussian-Minimum-Shift-Keyed (GMSK) signal for transmission in a first mode. The modulation loop () may include a phase-locked loop () with its frequency controlled by a &#x3a3;-&#x394; demodulation of a compensated version of the phase signal, or alternatively may produce a modulated signal from a direct digital synthesis circuit (). An amplitude signal is converted into an analog signal and applied to a single-sideband mixer () for combination with a frequency multiplied version of the phase-modulated signal (GMSK(t); PH(t)), producing an amplitude and phase modulated signal for transmission in a second mode.

Direct modulation architecture for amplitude and phase modulated signals in multi-mode signal transmission

A mobile radio telephone having a simplified architecture including a reduced number of integrated circuits and a reduced number of RF connections. A dual band, dual mode mobile phone can be constructed using either a single crystal reference oscillator or two crystals such that alternative symbol rates, channel spacings, or transmit/receive duplex spacings can be achieved.

Method and apparatus for generating a plurality of reference frequencies in a mobile phone using a common crystal reference oscillator

Simplified reference frequency distribution in a mobile phone

An RF amplifier for a transmitter develops a phase modulation command representing a desired phase modulation of an RF signal, and an amplitude modulation command representing a desired amplitude modulation of the RF signal. An oscillator develops an RF input signal phase modulated based on the phase modulation command. A power amplifier receives the RF input signal and amplifies the RF input signal based on the amplitude modulation command to develop an RF output signal. A modulation control is operatively associated with the oscillator. The modulation control includes a phase memory for storing phase correction information correlating the amplitude modulation commands to a phase modulation error and a phase control for varying the phase modulation command based on the phase modulation error to correct for unintended phase errors created by amplitude modulation of the power amplifier.

Amplitude modulation to phase modulation cancellation method in an RF amplifier

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 homodyne receiver according to the present invention includes a signal input and first and second mixers coupled to the signal input. A local oscillator provides a reference signal at the frequency of modulation of the input signal. The reference signal output by the local oscillator is passed through a switchable phase change element, the output of which is coupled directly to the first mixer and indirectly to the second mixer through a second phase change element. The switchable phase change element changes the phase of an input signal by a predetermined phase based on the state of a control input, such that the output of the phase change element in one state is &pgr; radians out of phase with the output of the phase change element in the other state. The second phase change element changes the phase of an input signal by &pgr;/2 radians. The outputs of the mixers are coupled to a pair of switchable inverters and low pass filters. Switching of the switchable phase change element and the switchable inverters is controlled by a switching oscillator.

Direct conversion receiver

According to a second embodiment of the invention, a mobile phone receiver comprises a first down converter using a first local oscillator frequency which can be tuned in frequency steps by a programmable digital frequency synthesizer PLL which is locked to a reference frequency. The first down converter converts received signals to a first IF for filtering. A second down converter using a second local oscillator converts first IF signals to a second IF. The second local oscillator frequency is generated using a second digital frequency synthesizer PLL which locks the second oscillator to the reference frequency. A third down converter mixes the transmit frequency with the first local oscillator frequency to produce a lock frequency. A third digital frequency synthesizer PLL compares the lock frequency and the reference frequency to control generation of the transmit frequency.

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Durham, NC, United States of America

Charles Gore