Patent ID: 11960955
Assignee: IMPINJ, INC.
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 7:
8. A Radio-Frequency Identification (RFID) reader that transmits commands to an RFID tag using amplitude modulation (AM) of a radio frequency (RF) waveform and is configured to avoid powering-down the RFID tag when changing a frequency of the RF waveform, the reader comprising:
a transceiver configured to transmit RF waveforms; and
a processor coupled to the transceiver and configured to:
amplitude-modulate the RF waveform with a command, wherein the modulation includes a low-amplitude pulse;
cause the transceiver to transmit the modulated RF waveform at a first frequency;
during the low-amplitude pulse, switch the frequency of the RF waveform from the first frequency to a second frequency different from the first frequency; and
at the end of the pulse, cause the transceiver to transmit the RF waveform at the second frequency, wherein an average power of the entire modulated RF waveform is sufficient for the tag to receive the command.