Patent ID: 7075948
Filing Date: 2006-07-11
Classification: H04L

Abstract:
1. A frequency offset detector for measuring a frequency offset sign and magnitude of a received complex signal, comprising: a first detector operating to detect at least one quadrant transition of the received complex signal in a counter-clockwise rotation direction; a first accumulator that accumulates a number of counter-clockwise quadrant transitions detected by the first detector during a time period; a second detector operating to detect at least one corresponding quadrant transition of the received complex signal in a clockwise rotation direction; a second accumulator that accumulates a number of clockwise quadrant transitions detected by the second detector during the same time period; and a subtractor that subtracts from the accumulated counter-clockwise quadrant transitions the clockwise quadrant transitions to obtain a difference value, a sign of that difference value being indicative of the frequency offset sign and a magnitude of that difference value being indicative of the frequency offset magnitude.