- SS-HQ1 Application Notes -
Ver.1.0.0 January 7, 2005
221
Table 12.2-28 External Input Signal (VBS Lock (VBSLHR) Mode)
Pin Name(Pin No)
I/O signals
S0(44pin)
Connected (3.3V) power supply
S3(48pin) FSC
signal
EXVIDEOY(57pin) EXT-VIDEO-Y(1Vpp:
Analog
signal)
EXVIDEO(58pin) EXT-VIDEO(1Vpp:
Analog
signal)
The external video signal input to EXVIDEOY should be passed through the LPF. This serves to remove the
subcarrier component, and is a countermeasure against noise in cases where no external video signal is input.
The phase of the FSC signal output from S4 (pin 49) must be adjusted and the signal must be re-input to S3
(pin 48).
Internal phase comparison
•
FSC phase comparison
The burst component of EXT-VIDEO, which is input to EXTVIDEO (pin 58) from SYNCSEP inside the
CXD3172AR, is amplified and digitized, and the resulting signal is phase-compared against the FSC signal. The
result of this phase comparison is output through S2 (pin 47) as the FSC comparison output. The FSC
comparison output should be applied to an LPF (SC) and fed back to the VCXO on the 8FSC side to form the
subcarrier PLL.