- SS-HQ1 Application Notes -
Ver.1.0.0 January 7, 2005
219
Fig 12.2-34 PCOMP output waveform (unlocked)
•
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.
PCOMP
output
Ch1
Ch2
[TRIGGER]
PCOMP Waveforms
Instability
20.0us / DIV
EXT-VIDEO
EXVIDEOY
input
Ch1:500mV / DIV
Ch2:1.00V / DIV