Patent ID: 6498822
Filing Date: 2002-12-24
Classification: H04L

Abstract:
A frequency and timing synchronization circuit making use of a chirp signal for detecting a frequency shift and a synchronization timing of a received signal modulated with a transmission chirp signal; the frequency and timing synchronization circuit comprising:a chirp signal generator for generating a reference chirp signal having the same chirp rate with the transmission chirp signal and a conjugate complex signal of the reference chirp signal; a first demodulator for obtaining a first in-phase complex signal and a first quadrature-phase complex signal by demodulating the received signal with the reference chirp signal and the conjugate complex signal, respectively; a frequency offset circuit for obtaining an offset signal by shifting a frequency of the received signal by an offset frequency; a second demodulator for obtaining a second in-phase complex signal and a second quadrature-phase complex signal by demodulating the offset signal with the reference chirp signal and the conjugate complex signal, respectively; and a detector unit for detecting the frequency shift and the synchronization timing according to a first and a second peak frequency, the first peak frequency giving a maximum power spectrum among frequency components of the first and the second in-phase complex signal, and the second peak frequency giving a maximum power spectrum among frequency components of the first and the second quadrature-phase complex signal.