A carrier restoration apparatus for acquiring a frequency offset and tracking
a
phase jitter from a pass-band digital signal having the frequency offset and the
phase jitter is disclosed. In the apparatus, a frequency acquisition PLL section
for acquiring the frequency offset and a phase tracking PLL section for tracking
the residual phase jitter are separately constructed, and the apparatus operates
in two modes for first acquiring the frequency offset and then tracking the residual
phase jitter. Thus, a rapid acquisition/tracking is performed so as to minimize
the frequency offset and phase jitter of several hundred KHz produced from a tuner
or an RF oscillator, and a high-reliability acquisition/tracking can be performed
even under the low SNR and serious channel ISI (i.e., ghost).