Tx cancellation system by source injection
AssigneeACCO Corporation
InventorsZakaria Settaf, Hervé Cam, Guillaume Blamon, Francis Huin
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Abstract
Cancellation of a leaked transmission signal received together with a received signal is cancelled at a receiver amplifier in a system made up of the receiver amplifier, a power amplifier, and a duplexer that couples both to an antenna. A portion of the amplified transmission signal from the power amplifier is split off prior to the duplexer. That portion is controllably applied to the receiver amplifier. A feedback loop monitors the amplified output of the receiver amplifier and varies the gain and phase of the portion of the amplified transmission signal in order to minimize the amount of transmission signal in the amplified output of the receiver amplifier.
Claims12
A circuit comprising:
- a power amplifier having an input for receiving an input signal and having an output for a transmission signal that is the input signal amplified;
- a receiver amplifier having an output for an amplified receiver signal;
- a duplexer configured to connect to an antenna and to connected to the power amplifier to receive the transmission signal therefrom, and connected to the receiver amplifier, the duplexer providing an antenna signal from the antenna to an input of the receiver amplifier;
- a directional coupler disposed between the power amplifier and the duplexer and configured to pass a majority of the transmission signal to the duplexer and further configured to direct a balance of the transmission signal to a feedback loop;
- the feedback loop being configured to adjust a gain and a phase of the balance of the transmission signal to produce a phase and gain adjusted signal, the feedback loop being further configured to apply the phase and gain adjusted signal to the receiver amplifier.
A method for cancelling a leaked transmission signal at a receiver amplifier, the method comprising:
- transmitting by
- amplifying a first signal to produce a first amplified signal,
- splitting the first amplified signal into a first portion comprising a majority of the first amplified signal and a second portion comprising a balance of the first amplified signal, and
- transmitting the first portion to a duplexer coupled to an antenna, wherein a segment of the first portion becomes the leaked transmission signal;
- and
- receiving while transmitting by
- receiving from the antenna, through the duplexer, at the receiver amplifier a second signal,
- receiving through the duplexer at the receiver amplifier the leaked transmission signal, and
- applying the second portion of the first amplified signal to the receiver amplifier to cancel the leaked transmission signal.
Dependencies are inferred from the claim text.