Patent ID: 8010316

Claim:
A method for determining a phase shift of an echoed signal in response to a transmitted signal incident onto an object, the method comprising: receiving a second signal, the second signal being a reflection of a first signal incident on the object, wherein the first signal is modulated by one or more pulses having a defined modulation frequency; using a processor for determining a first sum of points in time within an overlap region of the first and second signals, wherein the overlap region includes a portion of both respective pulses of the first and second signals; determining a second sum of points in time within the respective one of the pulses of the second signal; and determining a fraction of the first signal that is overlapped by the second signal upon dividing the first sum of points in time by the second sum of points, wherein the phase shift of the second signal is provided upon subtracting the determined fraction of the first signal from a selected value.