- SS-HQ1 Application Notes -
Ver.1.0.0 January 7, 2005
217
12.2.10. VBS Lock Mode (VBSLHP)
VBS Lock (VBSLHP) synchronizes the camera vertical, horizontal, and subcarrier phases to the external video
signal.
A reset operation is performed in the vertical direction, and a PLL operation is performed in the horizontal
direction and on the subcarrier.
The SGMODE setting is 3[h]. (See
Only a limited number of operation modes can be used with VBSLHP. For details, see appendix 13.1 (“External
Synchronization Evaluation Results”).
System Configuration
The master signal is an external video signal (EXT-VIDEO). A 1Vpp video signal (analog) is input to
EXVIDEOY (pin 57) and EXVIDEO (pin 58). The external video luminance signal (EXT-VIDEO-Y) input to
EXVIDEOY (pin 57) is divided inside the CXD3172AR between a vertical direction signal (EXT-VD) and
horizontal direction signal (EXT-HD). EXT-VD resets the CXD3172AR’s internal vertical direction counter. The
EXT-HD signal and MCK-frequency-divided HD (MCK-HD) signal are phase-compared inside the CXD3172AR.
The burst component extracted inside the CXD3172AR from EXT-VIDEO (input to EXVIDEO (pin 58)) is
amplified and digitized, and the resulting signal is phase-compared against the FSC signal.
X’tal oscillation is used for the VCXO on the ECK side. We recommend using X’tal oscillation for the VCXO on
the MCK side.
A system block diagram is shown in
. The external input signal is presented in
Fig 12.2-32 VBS Lock (VBSLHP) mode
CXD3172AR
42
43
88
87
86
46
47
48
44
49
57
58
ESC
I
ESC
O
EC
K
PC
O
M
P
EXVID
E
O
Y
EXVID
E
O
S0
S1
S4
S3
S2
MCK
3.3V
LPF
(H-PLL)
VCXO
VCXO
LPF
(SC)
LPF
EXT-VIDEO
ANALOG
SHIFTER