I. Panayiotopoulos et al., Anti-hangup binary quantized DPLL technique for timing recovery in QAM symbol-rate sampled receivers, IEEE COMMUN, 49(2), 2001, pp. 360-374
This paper presents the statistical performance analysis of a decision dire
cted timing recovery scheme based on a digital phase-locked loop (DPLL) tha
t uses binary quantization and employs an adaptive sequential loop filter (
LF) devised in order to prevent the adversary hang-up phenomenon. The propo
sed loop is analyzed by exercising Markovian analytical techniques on a sim
plified two-dimensional Markov chain approximation. Both the tracking and a
cquisition performances are examined in cases of M-ary quadrature amplitude
modulation input signals. Numerical results, validated further by computer
simulations, in essence show that the employed anti-hangup sequential LF s
peeds up the acquisition process by preventing the synchronizer from excess
ively long hang-ups. Compared to the classical nonadaptive binary quantized
DPLL synchronizer, the loop dth the proposed adaptation mechanism gains up
to an order of magnitude in response time over the hang-up effect, at a mi
nor cost in its steady-state tracking performance.