Chapter 6
Sync, Deflection & High Voltage
The Overall Sync, Deflection and Hign Voltage cir- cuitry in the V23 is shown in the Block Diagram at the top of the page. The V23 can display either of two scanning formats, 480p or 1080i. The horizon- tal scanning frequency for 480p is 31.5 kHz, and 1080i is 33.75 kHz.
Conventional 480i TV signals have a scanning rate of 15.75 kHz. For these signals, line doubling cir- cuitry changes the signal format from 480i to 480p.
In NTSC and Component format signals, horizontal and vertical sync must be extracted from the Y sig- nal by the NTSC Decoder. For the DTV Input, the signal can be either Y,Pr,Pb or RGB/HV, sometimes referred to as
Sync Select circuitry selects the Main picture sync source. The selected output is used to synchronize the Horizontal and Vertical Deflection Generators. If the source signal is 480i, horizontal sync is doubled, before synchronizing the Horizontal Drive Generator.
Horizontal deflection drive is amplified by the Hori- zontal Output circuitry and directed to the horizon- tal windings in the Deflection Yokes. The signal from the Horizontal Output is also directed to HV Drive circuitry. HV Drive is amplified at directed to the Flyback transformer.
Vertical sync synchronizes the Vertical Deflection Generator. Output from the Vertical Generator is amplified in the Vertical Output circuitry and directed to the vertical windings in the Deflection Yokes.