Sony UP-21MD Service Manual page 60

(2) Sync generator biock
A sync signal for the monitor output must be generated by this unit when a memory image is selected
for the monitor output or when no input signal exists. This circuit is peripheral circuit IC406._
1C406 is a sync signal generator compatible with NTSC and PAL systems. IC406 generates video
pulses (CSYNC, ODD/EVEN, HD, VD, and SC signals) by inputting a clock. These video pulses are
sent to IC407 and a frame memory block.
NTSC and PAL are switched by Q408. For NTSC, the X401 block is turned on, and a clock of
14.31818 MHz is sent. For PAL, the X402 and X403 blocks are turned on, and clocks of 14.1875
MHz and 17.734475 MHz are sent, respectively. For PAL, a subcarrier (SC signal) is synchronized
with a horizontal sync signal by VCXO (peripheral circuits Q407 and Q409).
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Fig. 1-9 Syne Generator Block