  Continuum reverberation mapping with high-cadence, long-term UV/optical
monitoring of Active Galactic Nuclei (AGNs) enables us to resolve the AGN
central engine sizes on different timescales. The frequency-resolved time lags
of NGC 5548 (the target for the AGN STORM I campaign) are inconsistent with the
X-ray reprocessing of the classical Shakura $\&$ Sunyaev disk model. Here we
show that the frequency-resolved time lags in NGC 5548 can be well produced by
the Corona-Heated Accretion-disk Reprocessing (CHAR) model. Moreover, we make
the CHAR model predictions of the frequency-resolved time lags for Mrk 817, the
source of the AGN STORM II campaign. We also obtain the frequency-resolved time
lags as a function of the black-hole mass and Eddington ratio, which is valid
for black-hole masses from $10^{6.5}$ to $10^9\ M_{\odot}$, and Eddington
ratios from 0.01 to 1. Moreover, we demonstrate that, with the time spans of
current continuum reverberation-mapping campaigns, the lag-luminosity relation
of the CHAR model can be $\tau_{\mathrm{gz}}\propto
L_{\mathrm{5100}}^{0.55\pm0.04}$, which is consistent with observations. Future
observations can test our results and shed new light on resolving the AGN
central engine.
