An RF transceiver with a low power chirp acquisition mode includes a pulse detection circuit, which initiates a low power chirp acquisition mode when an appropriate input pulse is received. While in chirp acquisition mode, all transceiver circuitry not required to determine the chirp rate is powered...http://www.google.com/patents/US6683904?utm_source=gb-gplus-sharePatent US6683904 - RF transceiver with low power chirp acquisition mode
