Patent ID: 6947860

Claim:
A method to remove undesirable decaying response signals from a receive signal for electronic article surveillance tag detection, comprising: obtaining a first replica signal of a selected portion of the receive signal by gradually adapting said first replica signal to the characteristics of the selected portion of the receive signal; subtracting said first replica signal from said receive signal; obtaining a second replica signal of the selected portion of the receive signal by quickly adapting said second replica signal to the characteristics of the selected portion of the receive signal; comparing the phase of the second replica signal to the phase of the receive signal minus the first replica signal to determine a phase difference; if the phase difference becomes nearly constant for a first preselected period of time and during the first preselected period of time the amplitude of said receive signal is greater than a threshold noise value, then the first replica signal adapts quickly to the characteristics of the selected portion of said receive signal; and, after a second preselected period of time the first replica signal again adapts gradually to the characteristics of the selected portion of said receive signal.