Importance

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Abstract

The RFID interrogator further comprises a microcontroller module adapted to provide high level commands to the interrogator, a DSP module for processing received/transmitted data and controlling radio operations, and a radio module for transmitting and receiving RF signals to/from an RFID transponder. A first embodiment of the RFID interrogator comprises an RF carrier source providing a carrier signal, a processor providing an information signal, and plural modulation stages coupled to the RF carrier source for modulating the information signal onto the carrier signal using on/off keying modulation. The plural modulation stages are controlled in unison by control signals the said processor. The plural modulation stages provide dynamic range of greater than 25 dB between respective on and off states of the modulated signal. A second embodiment of the RFID interrogator comprises an RF carrier source providing a carrier signal, a modulator receiving the carrier source and modulating an information signal thereon to provide a modulated RF signal, and an amplification stage coupled to the modulator. The amplification stage splits the modulated RF signal into first and second components, and amplifies the first and second components separately. The first and second components are thereafter recombined. The split operation of the amplification stage provides a better match with the downstream transmission path than an individual amplifier. A third embodiment of the RFID interrogator comprises an RF carrier source providing a carrier signal, a demodulator combining a received signal with the RF carrier to provide a baseband signal, and an attenuator coupled to the demodulator for absorbing high frequency components of the baseband signal. The baseband signal further comprises in phase (I) and quadrature phase (Q) components. The high frequency components of the baseband signal pass through the high-pass filter to the resistor termination, where they are absorbed.

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First Claim