Patent ID: 7664461

Claim:
A reader for a radio frequency identification system, comprising: a transmitter operable to generate an outbound radio frequency (RF) signal; a receiver operable to receive an inbound RF signal having a frequency similar to a frequency of said outbound RF signal, said inbound RF signal including a blocking signal corresponding to said outbound RF signal and a modulated RF signal produced responsive to said outbound RF signal, said receiver comprising: a low noise amplifier operably coupled to amplify said inbound RF signal to produce an amplified inbound RF signal, a block cancellation module operably coupled to receive said outbound RF signal from said transmitter and to substantially cancel said blocking signal from said amplified inbound RF signal using said outbound RF signal and substantially pass said modulated RF signal, wherein said block cancellation module comprises: a controller operably coupled to receive said outbound RF signal and to produce a cancellation signal from said outbound RF signal; a carrier injection module operably coupled to receive said inbound RF signal and said cancellation signal and to substantially cancel said blocking signal and substantially pass said modulated RF signal using said cancellation signal; and a feedback loop operably coupled to control said cancellation signal based on said modulated RF signal; a down-conversion module operably coupled to convert said modulated RF signal to a near baseband signal, and a digitizing module operably coupled to convert said near baseband signal into a digital baseband signal; and a processing module operably coupled to convert said digital baseband signal into inbound digital symbols.