Mitsubishi Electric HITACHI VS-50111 Troubleshooting Manual page 39

The above Block Diagram shows the Overall Deflec-
tion and HV circuitry in the V20. The V20 can display
either of two scanning formats, 480p or 1080i. The
horizontal scanning frequency for 480p is 31.5 kHz, and
for 1080i is 33.75 kHz.
Conventional TV signals are 480i and have a scanning
rate of 15.75 kHz. 480i signal scanning rates are
doubled, changing the signal format from 480i to 480p.
In NTSC and Component format signals, horizontal and
vertical sync must be extracted from the Y signal. If the
1080i signal from a Set Top Box is RGB, sync is either
on the G signal or separate horizontal and vertical sync
are output from the box.
Chapter 6
Deflection & HV Circuitry
V20 Chassis Technical Training
Sync Select circuitry selects Main picture sync source.
The selected output is used to synchronize the Hori-
zontal and Vertical Deflection Generators. If the source
signal is 480i, horizontal sync is doubled, before syn-
chronizing the Horizontal Drive Generator.
Horizontal deflection drive is amplified by theHorizontal
Output circuitry and directed to the horizontal 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 Gen-
erator. Output from the Vertical Generator is amplified
in the Vertical Output circuitry and directed to the ver-
tical windings in the Deflection Yokes.
6-1
and Troubleshooting Guide