Improved carrier recovery and symbol timing systems and methods suitable
for use in connection with a dual-mode QAM/VSB receiver system is disclosed. Carrier
and symbol timing acquisition and tracking loops are phase/frequency locked to
an inserted pilot signal provided in an input VSB spectrum at a given frequency.
An input spectrum is centered about baseband and the pilot is extracted by an equivalent
filter which functions as a bandpass filter having pass bands centered about the
pilot frequency. Since the pilot signal's frequency is given, its position in the
frequency domain for any sampling frequency, is deterministic. The receiver's sampling
frequency is provided such that the relationship is expressed as fc=fS/4.
When tracked by a phase-lock loop, the pilot signal will appear at the correct
location in the spectrum if the sampling frequency fS is correct, and
will be shifted in one direction or the other if the sampling frequency fS
is too high or too low.