Method of demodulating chirp spread spectrum

摘要

A digital circuit is used to demodulate a linear chirp spread spectrum signal. The digital circuit uses a counter which is clocked so as to count during the time period between the pulses of a chirp signal. The circuitry also uses a digital filter to determine whether the frequencies of the linear chirp signal are within the correct bandwidth. The output of the counter is compared with the previous count to produce a difference count. A processor uses this difference count value to determine the characteristics of a chirp signal being decoded. A difference signal test circuit provides a digital filter for the difference count to eliminate spurious noise conditions.