RFID reader and method for removing a transmission carrier leakage signal
First Claim
1. A radio frequency identification (RFID) reader comprising:
- a transmitting circuit which generates a transmitted signal to operate an RFID tag;
a receiving circuit which receives a received signal including a tag signal from the RFID tag and a transmission carrier leakage signal leaking from the transmitting circuit; and
a leakage removing circuit which senses a phase and an amplitude of the transmission carrier leakage signal inputted to the receiving circuit, converts the transmitted signal from the transmitting circuit into a signal having a phase opposite to that of the transmission carrier leakage signal and an amplitude equal to that of the transmission carrier leakage signal, and synthesizes the converted signal and the received signal inputted to the receiving circuit.
1 Assignment
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Accused Products
Abstract
A radio frequency identification (RFID) reader is provided, having a transmitting circuit that generates a transmitted signal to operate an RFID tag, a receiving circuit that receives a received signal including a tag signal from the RFID tag and a transmission carrier leakage signal leaking from the transmitting circuit, and a leakage removing circuit that senses a phase and amplitude of the transmission carrier leakage signal inputted to the receiving circuit, converts the transmitted signal from the transmitting circuit into a signal having a phase opposite to that of the transmission carrier leakage signal and an amplitude equal to that of the transmission carrier leakage signal, and synthesizes the converted signal and the received signal inputted to the receiving circuit.
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Citations
9 Claims
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1. A radio frequency identification (RFID) reader comprising:
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a transmitting circuit which generates a transmitted signal to operate an RFID tag; a receiving circuit which receives a received signal including a tag signal from the RFID tag and a transmission carrier leakage signal leaking from the transmitting circuit; and a leakage removing circuit which senses a phase and an amplitude of the transmission carrier leakage signal inputted to the receiving circuit, converts the transmitted signal from the transmitting circuit into a signal having a phase opposite to that of the transmission carrier leakage signal and an amplitude equal to that of the transmission carrier leakage signal, and synthesizes the converted signal and the received signal inputted to the receiving circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A radio frequency identification (RFID) reader having a transmitting circuit generating a transmitted signal to operate an RFID tag and a receiving circuit receiving a received signal including a tag signal from the RFID tag and a transmission carrier leakage signal leaking from the transmitting circuit, the RFID reader comprising:
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a gain amplifier converting the amplitude of the transmitted signal from the transmitting circuit; a phase shifter generating an offset signal by adjusting the phase of the transmitted signal from the gain amplifier so that the phase of the transmitted signal becomes opposite to the phase of the transmission carrier leakage signal; and a signal detector installed on the receiving circuit to detect the transmission carrier leakage signal inputted to the receiving circuit and the offset signal generated through the gain amplifier and the phase shifter.
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9. A method for removing a transmission carrier leakage signal in a radio frequency identification (RFID) reader, the method comprising:
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measuring the amplitude and phase of a transmission carrier leakage signal; creating an offset signal by adjusting the transmitted signal such that the offset signal has an amplitude equal to the transmission carrier leakage signal and a phase opposite to the transmission carrier leakage signal; and synthesizing the offset signal and a signal received from an RFID tag to remove the transmission carrier leakage signal from the received signal.
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Specification