RFID reader with adaptive carrier cancellation
First Claim
1. A Radio Frequency Identification (RFID) reader, comprising:
- a first mixer receiving an incoming signal;
a second mixer receiving the incoming signal;
circuitry for adding a portion of an outgoing signal to an input of the incoming signal;
a first analog feedback loop coupling an output of the first mixer to the circuitry for adding the portion of the outgoing signal to the input of the incoming signal; and
a second analog feedback loop coupling an output of the second mixer to the circuitry for adding the portion of the outgoing signal to the input of the incoming signal, wherein an amount of outgoing signal added to the incoming signal is dependent upon feedback signals in the feedback loops.
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Accused Products
Abstract
An RFID reader includes first and second mixers receiving an incoming signal, circuitry for adding a portion of an outgoing signal to an incoming signal, first and second analog feedback loops coupling outputs of the first and second mixers to the circuitry for adding the outgoing signal to the incoming signal. An amount of outgoing signal added to the incoming signal depends on signals in the feedback loops. An RFID reader in another embodiment of the present invention includes a first mixer receiving an incoming signal, a second mixer receiving the incoming signal, an AC-coupled section coupled to the mixer outputs, and a DC-coupled section coupled to the mixer outputs. An RFID reader in another embodiment of the present invention includes an analog loop for adaptive carrier signal cancellation from an incoming signal, and a digital loop for controlling a gain of the incoming signal. Methods are also presented.
68 Citations
28 Claims
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1. A Radio Frequency Identification (RFID) reader, comprising:
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a first mixer receiving an incoming signal;
a second mixer receiving the incoming signal;
circuitry for adding a portion of an outgoing signal to an input of the incoming signal;
a first analog feedback loop coupling an output of the first mixer to the circuitry for adding the portion of the outgoing signal to the input of the incoming signal; and
a second analog feedback loop coupling an output of the second mixer to the circuitry for adding the portion of the outgoing signal to the input of the incoming signal, wherein an amount of outgoing signal added to the incoming signal is dependent upon feedback signals in the feedback loops. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A Radio Frequency Identification (RFID) reader, comprising:
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a first mixer receiving an incoming signal;
a second mixer receiving the incoming signal;
an Alternating Current (AC)-coupled section coupled to outputs of the mixers; and
a Direct Current (DC)-coupled section coupled to the outputs of the mixers. - View Dependent Claims (10, 11, 12)
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13. A Radio Frequency Identification (RFID) reader, comprising:
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an analog loop for adaptive carrier signal cancellation from an incoming signal; and
a digital loop for controlling a gain of the incoming signal.
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14. A method for processing a Radio Frequency (RF) signal, comprising:
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receiving an incoming signal;
adding a portion of an outgoing signal into the incoming signal, an amount of the outgoing signal being added to the incoming signal being controlled by feedback loops coupled to mixer outputs;
monitoring an input to the mixers via a digital loop; and
controlling a gain of the incoming signal having the portion of the outgoing signal added thereto based on the monitoring. - View Dependent Claims (15)
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16. A method for processing a Radio Frequency (RF) signal, comprising:
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receiving an incoming signal;
separating the incoming signal into I and Q components;
extracting higher frequency signals from the I and Q components;
extracting data from the higher frequency signals;
extracting lower frequency signals from the I and Q components; and
feeding the lower frequency signals to a noise cancellation circuit.
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17. A Radio Frequency Identification (RFID) reader, comprising:
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a mixer receiving an incoming signal;
a first amplifier connected via a high pass filter coupled to an output of the mixer; and
a second amplifier connected via a low pass filter coupled to the output of the mixer. - View Dependent Claims (18, 19, 20)
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21. A Radio Frequency Identification (RFID) reader, comprising:
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a mechanism for transmitting an RF signal;
a mechanism for receiving an RF signal;
a mechanism for adding an in phase portion of the transmitted RF signal to an input of the received RF signal; and
another mechanism for adding a quadrature phase portion of the transmitted RF signal to the input of the received RF signal;
wherein the in phase and quadrature components are adjusted independently of each other. - View Dependent Claims (22, 23)
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24. An electronic circuit, comprising:
an RF modulator which can produce both amplitude modulated waveforms and phase modulated waveforms. - View Dependent Claims (25, 26, 27)
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28. An electronic circuit, comprising:
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a first amplifier with phase shifted input; and
a second amplifier with phase shifted input, wherein the phase relationship between the two amplifiers can be continuously varied by more than 180 degrees.
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Specification