RF TRANSCEIVER WITH LOW POWER CHIRP ACQUISTION MODE

摘要

An RF transceiver with a low power chirp acquisition mode includes a pulse detection circuit (12), 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 down, a low power fast hopping LO generator (32) is powered up to provide one or more LO signals to demodulate the incoming signal, and an active bandpass filter (24) connected to filter the demodulated output (22) is arranged to extend the width of its passband to include the chirp rate. The filtered signal (26) is digitized with an ADC (28) and processed to determine the incoming signal's chirp rate. Once the chirp rate is detected, the LO power generator (32) is powered down, the passband of the active bandpass filter (24) is narrowed, and the remaining receiver circuitry is powered up to dechirp the RF input signal.