According to one aspect of the present invention, there is provided a
method to backscatter modulate a first radio-frequency (RF) signal from a
radio-frequency identification (RFID) tag. An oscillator calibration
value is retrieved from a non-volatile memory associated with the RFID
tag. An oscillation frequency signal is generated within the RFID tag,
the generating of the oscillation signal being performed utilizing the
oscillator calibration value. A command signal is generated within the
RFID tag, the command signal being based on command data received at the
RFID tag in a second radio-frequency signal from an RFID reader. The
first radio-frequency signal is backscatter modulated in accordance with
both the oscillation frequency signal and the command signal.