  TV Col is a long-period eclipsing intermediate polar (IPs) prototype star for
the negative superhump (NSH) system. We investigate the eclipse minima, eclipse
depth, and NSH amplitude based on TESS photometry. Using the same analytical
method as SDSS J081256.85+191157.8, we find periodic variations of the O-C for
eclipse minima and NSH amplitudes with periods of 3.939(25) d and 3.907(30) d,
respectively. The periodic variation of the NSH amplitude of TV Col confirms
that periodic NSH amplitude changes in response to the tilted disk precession
may be universal, which is another evidence that the origin of the NSHs is
related to the tilted disk precession. We suggest that the NSH amplitude
variation may be similar to the superorbital signal, coming from the periodic
change in visual brightness of the energy released by streams touching the
tilted disk with tilted disk precession. Finally, we find for the first time
that the eclipse depth exhibits bi-periodic variations with periods of P1 =
3.905(11) d and P2 = 1.953(4) d, respectively. P2 is about half of P1 and the
disk precession period (P1~ Pprec ~ 2 * P2). We suggest that P1 may come from
the periodic change in the brightness of the eclipse center due to tilted disk
precession, while P2 may come from two accretion curtains precessing together
with the tilted disk, but more verification and discussion are necessary. The
discovery of bi-periodic variations in eclipse depth provides a new window for
studying IPs and tilted disk precession.
