System and method for controlling envelope tracking in a transmitter with closed loop power control
AssigneeBlackBerry Limited
InventorsStephen Arnold Devison, Christopher Eugene Snyder
Life of this patent
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Abstract
A system and method for controlling envelope tracking in a transmitter with closed loop power control, including up-converting and pre-amplifying a baseband signal to a pre-amplified RF signal, amplifying the pre-amplified RF signal, converting the envelope of the baseband signal into a shaped envelope signal, adjusting the gain of the pre-amplified RF signal, and adjusting the shape of the envelope signal in response to changes in the gain of the pre-amplified RF signal.
Claims19
A transmitter for a mobile communication device, comprising:
- a processor configured to generate a baseband signal and a control signal;
- a transmit signal path having a modulator configured to up-convert the baseband signal to an RF signal, and a transmit output stage configured to pre-amplify the RF signal;
- a power amplifier configured to amplify the RF signal that has been pre-amplified;
- an antenna configured to transmit the RF signal that has been amplified;
- an envelope tracking signal path comprising a function block configured to convert an envelope of the baseband signal into a shaped envelope signal;
- an automatic power control loop configured to:
- in response to receipt of the control signal from the processor and a feedback signal from an output of the power amplifier,
- generate a gain control signal to adjust a gain of the transmit output stage and concurrently control the function block of the envelope tracking signal path to convert the envelope of said baseband signal into the shaped envelope signal;
- and
- an envelope tracking modulator configured to receive the shaped envelope signal from the function block and provide power for the power amplifier that changes based on the shaped envelope signal.
A transmitter for a mobile communication device having a transmit signal path for up-converting and pre-amplifying a baseband signal to a preamplified RF signal, a power amplifier for amplifying the pre-amplified RF signal, an envelope tracking signal path for converting an envelope of the baseband signal into a shaped envelope signal, and an automatic power control loop configured to, in response to receipt of a control signal indicative of a change in power setting of the transmitter and a feedback signal from an output of the power amplifier, generate a gain control signal to adjust a gain of the transmit output stage, wherein the automatic power control loop is coupled to the envelope tracking signal path so that a function block of the envelope tracking path receives the gain control signal to concurrently control the conversion of the envelope of the baseband signal into the shaped envelope signal and the adjustment of the gain of the transmit output stage.
A method for controlling envelope tracking in a transmitter with closed loop power control, comprising
- up-converting and pre-amplifying, using a modulator and a transmit output stage, a baseband signal to a preamplified RF signal;
- amplifying, using a power amplifier, the pre-amplified RF signal;
- converting, using an envelope tracking signal path comprising a function block, an envelope of the baseband signal into a shaped envelope signal;
- generating a gain control signal using an automatic power control loop to adjust a gain of the pre-amplified RF signal and concurrently control the function block to convert the envelope of the baseband signal into the shaped envelope signal;
- and
- adjusting a shape of the shaped envelope signal in response to changes in the gain of the pre-amplified RF signal.
Dependencies are inferred from the claim text.