Patent ID: 7079605

Claim:
A method for frequency estimation in a QAM modem comprising the steps of: receiving I symbol and Q symbol components of a QAM symbol from a carrier recovery block; mapping said received QAM symbol as defined by its I symbol and Q symbol symbol components to a nearest QAM plant point using a slicer; determining an instant error power of said received QAM point by comparing said I symbol and Q symbol components of said received QAM symbol point and I plant and Q plant components of said nearest QAM plant point; averaging said instant error power over a plurality of incoming QAM symbols in time domain; excluding a DC component from said averaged error power; translating said averaged error power without said DC component from said time domain into a frequency domain in order to determine the frequency spectrum of said averaged error power; selecting the frequency spectrum component of said averaged error power with the maximum amplitude by using a peak detection; and determining said frequency offset as said maximum frequency spectrum component of said averaged error power.