Multi-channel receiver with improved AGC
First Claim
1. A receiver comprising:
- a gain section adapted to generate, based on a gain control value, an output signal from two or more differently-modulated received signals;
a detector adapted to generate an intensity value in response to the output signal;
a demodulator, for each received signal, adapted to demodulate the output signal into a corresponding demodulated signal having an amplitude;
a scalar, for each demodulated signal, adapted to scale the amplitude of the corresponding demodulated signal based on a corresponding scalar control value; and
a controller adapted to generate and adaptively change the gain control value and each scalar control value based on changes in the intensity value, wherein the controller is further adapted to delay a change of at least one of the scalar control values based on at least one processing delay associated with generating the corresponding demodulated signal.
7 Assignments
0 Petitions
Accused Products
Abstract
An improved multi-channel receiver for satellite broadcast applications or the like. In an exemplary embodiment, a primary AGC loop controls an analog sub-receiver adapted to simultaneously receive multiple signals. Multiple digital demodulators, coupled to the sub-receiver, demodulate the multiple received signals. Multiple secondary AGC loops, one for each received signal, compensate for variations in demodulated signal strengths caused by the primary AGC loop. A feed-forward AGC compensation technique generates scalar control values for scaling the demodulated signals before the demodulated signals are processed by the secondary AGC loops. This at least partially compensates for gain variations caused by the primary AGC, reducing received signal drop-outs before the secondary AGC loops can compensate for the gain variations. Because of systemic delays in the sub-receiver and the demodulators, the scalar control values are independently timed to be coincident with the variations in the demodulated signal strengths caused by the primary AGC loop.
-
Citations
11 Claims
-
1. A receiver comprising:
-
a gain section adapted to generate, based on a gain control value, an output signal from two or more differently-modulated received signals; a detector adapted to generate an intensity value in response to the output signal; a demodulator, for each received signal, adapted to demodulate the output signal into a corresponding demodulated signal having an amplitude; a scalar, for each demodulated signal, adapted to scale the amplitude of the corresponding demodulated signal based on a corresponding scalar control value; and a controller adapted to generate and adaptively change the gain control value and each scalar control value based on changes in the intensity value, wherein the controller is further adapted to delay a change of at least one of the scalar control values based on at least one processing delay associated with generating the corresponding demodulated signal. - View Dependent Claims (2, 3, 4)
-
-
5. A method for processing two or more differently-modulated received signals, the method comprising:
-
generating, based on a gain control value, an output signal from the two or more differently-modulated received signals; generating an intensity value in response to the output signal; demodulating, for each received signal, the output signal into a corresponding demodulated signal having an amplitude; scaling, for each demodulated signal, the amplitude of the corresponding demodulated signal based on a corresponding scalar control value; and generating and adaptively updating the gain control value and each scalar control value based on changes in the intensity value, wherein a change of at least one scalar control value is delayed based on at least one processing delay associated with generating the corresponding demodulated signal. - View Dependent Claims (6, 7, 8)
-
-
9. Apparatus for processing two or more differently-modulated received signals, the apparatus comprising:
-
means for generating, based on a gain control value, an output signal from the two or more differently-modulated received signals; means for generating an intensity value in response to the output signal; means for demodulating, for each received signal, the output signal into a corresponding demodulated signal having an amplitude; means for scaling, for each demodulated signal, the amplitude of the corresponding demodulated signal based on a corresponding scalar control value; and means for generating and adaptively updating the gain control value and each scalar control value based on changes in the intensity value, wherein a change of at least one scalar control value is delayed based on at least one processing delay associated with generating the corresponding demodulated signal. - View Dependent Claims (10, 11)
-
Specification