A system and method is provided for using a frequency division circuit to
produce a desired frequency in a radio frequency identification
transponder (RFID tag). In a preferred embodiment of the present
invention, an RFID tag includes a frequency division circuit connected to
a logic circuit and a oscillator. The logic circuit is adapted to
identify at least one frequency associated with a received RF signal
(e.g., the frequency of the signal, a frequency identified by the signal,
etc.). This frequency is then used by the frequency division circuit to
calibrate the frequency provided by the oscillator. In one embodiment of
the present invention, the frequency division circuit includes at least
one variable counter adapted to divide the frequency provided by the
oscillator (i.e., the oscillation frequency) by a programmable factor to
produce a desired frequency. The desired frequency is then provided to
the logic circuit and used to modulate a received RF signal. In another
embodiment of the present invention, the frequency division circuit
further includes at least one fixed counter, wherein the fixed counter is
not programmable. In this embodiment, the fixed counter is used to
produce a particular (lower) frequency, and the variable counter is used
to produce the desired frequency. Such an embodiment, for example, can be
used to decrease the amount of time required to produce a desired
frequency (e.g., by starting with a lower fixed frequency) and increase
the amount of time available to perform alternate functions (e.g.,
communicate with external devices, etc.).