Patent ID: 9729209
Date: 2017-08-08
CPC Classifications: G06K,H04B

Claim:
1. A Near Field Communication method for detecting whether a tag is present by a tag reader, the method comprising: stimulating an input of a transmitter of the tag reader with an input signal corresponding to an input sequence to generate an output signal of the transmitter, wherein the output signal represents the input signal convoluted by an impulse response of said transmitter under a current load condition of the transmitter; detecting the impulse response of said transmitter; evaluating the impulse response generated by said transmitter by comparing the impulse response to a time-varying lower limit and a time-varying upper limit of a predetermined envelope wherein the predetermined envelope is based on the input sequence; and assessing whether a tag is present based on said comparison of the impulse response to the time-varying lower limit and the time-varying upper limit of the predetermined envelope.