Patent ID: 7149259

Claim:
A QAM receiver, comprising: an input for receiving a hierarchical QAM signal, representing successive data points in the I-Q plane, each data point being in one of four quadrants; a level 1 decoder ( 304 ), responsive to a received data point, for detecting the quadrant in the I-Q plane of a received data point; translating circuitry ( 306 , 308 , 310 ), coupled to the hierarchical QAM signal input, for translating the received data point in the I-Q plane such that a center point of the detected quadrant is translated to the neighborhood of the origin of the I-Q plane; a level 2 decoder ( 312 ), responsive to the translated data point for detecting the quadrant of the translated data point CHARACTERIZED BY: calculating circuitry ( 320 , 322 , 324 ), coupled to the hierarchical QAM signal input, for calculating the location in the I-Q plane of the center-of-gravity of successive received data points in a quadrant; and the translating circuitry ( 306 , 308 , 310 ) further comprising circuitry for translating the received data point in the I-Q plane such that the calculated center-of-gravity location is translated to the origin of the I-Q plane.