Patent ID: 8063746
Filing Date: 2011-11-22
Classification: G06K,H04B,H04W,Y02D

Abstract:
1. A transponder detector comprising: an antenna assembly; a first circuit coupled to said antenna assembly, said first circuit configured to generate and transmit a first detection signal at a first frequency and a second detection signal at a second frequency via said antenna assembly; a second circuit coupled to said antenna assembly, said second circuit configured to receive response signals from said antenna assembly resulting from transmission of said first and second detection signals, wherein said response signals have a transponder detection parameter; and a controller operable to switch the detector between a detection mode and a data transaction mode, the controller further configured to detect the presence of a transponder having a transponder frequency in a proximal space of said transponder detector based on said detection parameter and upon such detection to switch the detector into the data transaction mode; wherein said first circuit comprises a series resistance having a first switched series resistor, a first resistance switch, a second switched series resistor, and a second resistance switch, and further comprises a parallel capacitance having a first switched parallel capacitor, a first capacitance switch, a second switched parallel capacitor, and a second capacitance switch, wherein the series resistance and parallel capacitance are connected by an inverter, and wherein said first and second detection signals are generated by cooperatively controlling positions of said first and second resistance and capacitance switches.