Patent ID: 7450670

Claim:
An error detector for generating a selected error signal for automatic gain control of received signals that are gain adjusted in a quadrature amplitude modulation (QAM) subsystem having a symbol demodulator for demodulating the received signals into symbol signals within a constellation space, the error detector comprising, a first switch for generating a current error signal from a current received signal and from a current symbol signal, the current error signal being a normalized ratio of the current received signal divided by the current symbol signal, and a second switch for generating the selected error signal being either the current error signal at a current symbol time or a previous error signal at a previous symbol time, the previous error signal being a previous current error signal at a previous symbol time when a respective previous symbol signal is distal to an origin in the constellation space, the selected error signal being the previous error signal when the current symbol signal is proximal to the origin in the constellation space, the selected error signal being the current error signal when the current symbol signal is distal to the origin in the constellation space.