Methods and techniques for 3g cellular transmitters
AssigneeBroadcom Corporation
InventorsAlireza Zolfaghari, Hooman Darabi, Ahmad Mirzaei
Life of this patent
Estimating the term…
Abstract
A transmitter operates in different modulation modes to support both GSM/EDGE and WCDMA cellular telephony applications. The transmitter modulates an outgoing signal to produce a complex modulated signal in a first modulation mode and a constant or variable envelope modulated signal in a second modulation mode. A local oscillation generator and mixer operate to up-convert the complex modulated signal to produce a modulated RF signal in the first modulation mode and to up-convert the phase component of the constant or variable envelope modulated signal to an RF phase signal and mix the RF phase signal with the envelope component thereof to produce the modulated RF signal in the second modulation mode.
Claims20
An RF transmitter for operating in different modulation modes, comprising:
- a digital processor coupled to receive a control signal and operable to modulate an outgoing digital signal based on the control signal to produce a complex modulated digital signal in a first modulation mode and one of a constant envelope modulated digital signal and a variable envelope modulated digital signal in a second modulation mode, the constant envelope modulated digital signal and the variable envelope modulated digital signal each include an envelope signal and a phase signal, wherein the envelope signal of the constant envelope modulated digital signal is a constant envelope signal and the envelope signal of the variable envelope modulated digital signal is a variable envelope signal;
- digital-to-analog converters for converting the complex modulated digital signal and the envelope signal, respectively, from digital signals to analog signals to produce a complex modulated analog signal in the first modulation mode and an analog envelope signal in the second modulation mode;
- a local oscillation generator operable to produce a local oscillation signal in the first modulation mode and coupled to receive the digital phase signal and operable to up-convert the digital phase signal to an RF phase signal in the second modulation mode;
- a mixer coupled to receive the complex modulated analog signal and the local oscillation signal and operable to up-convert the complex modulated analog signal to a modulated RF signal in the first modulation mode and coupled to receive the RF phase signal and the analog envelope signal and operable to produce the modulated RF signal based on the RF phase signal and the analog envelope signal in the second modulation mode;
- and
- a power amplifier coupled to receive the modulated RF signal and operable to produce an amplified modulated RF signal.
A method in an RF transmitter for operating in different modulation modes, comprising:
- modulating an outgoing digital signal to produce a complex modulated digital signal in a first modulation mode and one of a constant envelope modulated digital signal and a variable envelope modulated digital signal in a second modulation mode based upon a control signal, the constant envelope modulated digital signal and the variable envelope modulated digital signal each include an envelope signal and a phase signal, wherein the envelope signal of the constant envelope modulated digital signal is a constant envelope signal and the envelope signal of the variable envelope modulated digital signal is a variable envelope signal;
- converting the complex modulated digital signal and the envelope signal, respectively, from digital signals to analog signals to produce a complex modulated analog signal in the first modulation mode and an analog envelope signal in the second modulation mode;
- producing a local oscillation signal in the first modulation mode and an RF phase signal based upon the digital phase signal in the second modulation mode;
- mixing, in the first modulation mode, the complex modulated analog signal and the local oscillation signal to produce a modulated RF signal and, in the second modulation mode, the RF phase signal and the analog envelope signal to produce the modulated RF signal;
- and
- amplifying the modulated RF signal to produce an amplified modulated RF signal.
Dependencies are inferred from the claim text.