Television reciever with automatic gain control (AGC)
AssigneeSilicon Laboratories Inc.
InventorsLi Gao, Saroj Rout
Life of this patent
Estimating the term…
Abstract
A radio frequency (RF) signal is attenuated using first (220) and second (241) attenuation elements. In one embodiment an initial overall attenuation of the RF signal is set using both the first (220) and second (241) attenuation elements during a calibration period. The initial overall attenuation of the RF signal is adjusted using only the first attenuation element during a normal operation period. In another embodiment the initial overall attenuation is determined and is provided using either, only the first attenuation element (220) or both the first attenuation element (220) and the second attenuation element (241) based on a value of the initial overall attenuation.
Claims16
A method of automatic gain control (AGC) comprising:
- attenuating a radio frequency (RF) signal using first and second attenuation elements;
- determining an initial overall attenuation of the RF signal;
- selectively setting attenuations of the first attenuation element and the second attenuation element, based on a size of the initial overall attenuation, to configure the initial overall attenuation during a calibration mode;
- and
- adjusting the initial overall attenuation of the RF signal using only the first attenuation element during a normal operation period;
- and
- wherein selectively setting the initial overall attenuation further comprises:
- setting the initial overall attenuation using only the first attenuation element when the initial overall attenuation is less than a first amount;
- when the initial overall attenuation is between the first amount and a second amount, providing a first incremental attenuation above the first amount using both the first attenuation element and the second attenuation element;
- and
- when the initial overall attenuation is greater than the second amount, providing a second incremental attenuation above the second amount using only the first attenuation element.
A receiver comprising:
- a signal path having an input for receiving a radio frequency (RF) signal, and an output, and comprising first and second attenuation elements;
- a power detector having an input coupled to the output of the signal path, and an output;
- and
- an automatic gain control (AGC) circuit having an input coupled to the output of the power detector, and outputs coupled to the first and second attenuation elements, wherein the AGC circuit selectively sets attenuations of the first and second attenuation elements to provide an initial overall attenuation, based on a size of the initial overall attenuation;
- and
- wherein the AGC circuit adjusts a subsequent attenuation using only the first attenuation element in a normal operation mode;
- and
- wherein the AGC circuit further provides a first incremental attenuation above a first amount using both the first attenuation element and the second attenuation element when the initial overall attenuation is between the first amount and a second amount, and provides a second incremental attenuation above the second amount using only the first attenuation element when the initial overall attenuation is greater than the second amount.
Dependencies are inferred from the claim text.