Sub Contrast (Cutoff) Control; Brightness And Contract Control - Sony CPD-420GS Training Manual

Sub Contrast (Cutoff) control

The Sub Contrast levels can only be set by the DAS/CATS software for
White Balance adjustment. When Sub Contrast is adjusted, the Micro
IC1001 (N Board) via the I 2 C bus instructs IC001 to vary the DC level of
pin 3 (R BKG), pin 4 (G BKG) and pin 5 (B BKG). The DC levels are then
input to CUTOFF AMP IC004 pin 1 (B.IN), pin 3 (G.IN) and pin 4 (R.IN).
The output of IC004 pin 7 (R.OUT), pin 10 (G.OUT) and pin 13 (B.OUT)
are used to set the DC level of the R G B cathodes respectively. The
+180V DC with pull-up resistors R109, R209 and R309 and D106, D206
and D306 form the voltage divider network for the R G B cutoffs respec-
tively.
45

Brightness and Contract control

The Brightness and Contrast levels can be controlled either by the user or
via DAS/CATS software. When Brightness is adjusted, the Micro IC1001
(N Board) via the I 2 C bus instructs IC001 to vary the DC pedestal level of
the RGB outputs. When Contrast is adjusted, IC001 varies the P-P am-
plitude of the RGB outputs. IC001 outputs the RGB signal at pin 20 (R
OUT), pin 24 (G OUT) and pin 27 (B OUT).
IC001/20 R OUT