Patent ID: 8314685
Filing Date: 2012-11-20
Classification: H03G

Abstract:
1. In an RFID circuit for receiving a modulated RF signal having an envelope corresponding to digital coding of information, a method of detecting the signal, comprising: receiving a signal having a signal strength dependent on distance from an interrogator including a preamble and having a first time in a first logic state and having a second time in a second logic state; dynamically determining a weighted average voltage from the preamble in response to the first time and the second time, the weighted average voltage being between voltages representing the first logic state and the second logic state and being determined by the relative number of the first and second logic states in the preamble; generating a voltage representative of the envelope; controlling a value of the envelope voltage utilizing the weighted average voltage from the preamble to generate a value closer to or equal to an ideal comparison voltage; and comparing the comparison voltage to the received signal to produce an output signal in response to one of the first and second logic states.