Patent ID: 7796713
Filing Date: 2010-09-14
Classification: H04N

Abstract:
1. An automatic gain control device in a digital broadcast receiver, the device comprising: an AGC (automatic gain controller) configured to receive an input signal, a predetermined power reference value and an AGC step control signal, to obtain a gain error value based on the input signal and the predetermined power reference value, to determine one of a plurality of operational areas according to the AGC step control signal, to compensate the obtained gain error value according to the determined one of a plurality of operational areas and to generate an RF gain control signal and an IF gain control signal according to the compensated gain error value; and a lock detector configured to receive the obtained gain error value and the predetermined power reference value, to obtain an average gain error value of the obtained gain error value and to generate the AGC step control signal and an AGC lock/unlock signal based on the average gain error value and the predetermined power reference value, wherein the lock detector is configured to integrate the obtained gain error value in a predetermined period and to obtain the average gain error value from the integrated gain error value, and wherein the lock detector comprises: