RFID reader front end
First Claim
1. A digital receiver circuit comprising:
- an analog receiver circuit, the analog receiver circuit producing inphase and quadrature signals from received signals and having a first analog inphase/quadrature switch for controlling which of the inphase and quadrature signals are sent for digitizing; and
a single analog to digital converter connected to the analog receiver circuit for digitizing signals received from the analog receiver circuit.
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Accused Products
Abstract
An RFID reader analog front end architecture employs multiplexed use of a single analog to digital converter in order to digitize the inphase and quadrature components of the incoming signal from the reader'"'"'s receiving antenna. The Type 1 architecture includes an analog I/Q switch that controls which of the baseband signals will be digitized by a single Analog to Digital Converter. In the Type 2 architecture, the I/Q switch is moved so that it is directly adjacent to the receive mixers, requiring only one antialiasing filter block and gain block. In the Type 3 architecture, one mixer and its associated filtering chain are eliminated. The Type 4 architecture provides for selection of transmitter phase basis by means of an I/Q switch operating under control of the DSP that phase-shifts the transmitter with respect to the receiver.
37 Citations
20 Claims
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1. A digital receiver circuit comprising:
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an analog receiver circuit, the analog receiver circuit producing inphase and quadrature signals from received signals and having a first analog inphase/quadrature switch for controlling which of the inphase and quadrature signals are sent for digitizing; and
a single analog to digital converter connected to the analog receiver circuit for digitizing signals received from the analog receiver circuit. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A RFID reader front end comprising:
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a transmitter for querying an RFID tag;
an analog receiver circuit, the analog receiver circuit producing inphase and quadrature signals from signals received from the RFID tag and having a first analog inphase/quadrature switch for controlling which of the inphase and quadrature signals are sent for digitizing;
a single analog to digital converter connected to the analog receiver circuit for digitizing signals received from the analog receiver circuit; and
a digital signal processor for processing digitized signals from the analog to digital converter and controlling the first inphase/quadrature switch. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method for converting received analog radio frequency signals to digital signals, comprising the steps of:
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producing inphase and quadrature signals from a received analog radio frequency signal;
providing a first analog inphase/quadrature switch for selecting which one of the inphase and quadrature signals is sent for digitizing; and
sending the selected signal to a single analog to digital converter for digitizing. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification