NEC MultiSync FP1370 Service Manual page 135

IMAGE
②Phase distortion correction circuit
This model has 4 phase distortion correction items. (SIDE PIN BALANCE, TILT, CORNER TOP
BALANCE, CORNER BOTTOM BALANCE). The distortion correction signal is output from 1bit D/A
converter at pin 57, and is integrated by integration circuit which is composed of R525 and C519. This
integrated signal is added to filter terminal at pin 20 (PLL2 filter circuit) via C508 and R505.
The figure 2.8. shows the screen image and voltage waveform at C519, when the phase distortion
correction are operated by OSM.
1bit DAC
57
Integration Circuit
C524 WAVE
IN/OUT
ALIGN
CORNER
CORNER
BOTTOM
S-WAVE
SIDE WING
MIN. OSM MENU
(Fig. 2.6) Voltage at C524 and screen image
Approx.1Vdc
C508
R506
R526
C519
(Fig. 2.7) phase distortion correction circuit
C524 WAVE IMAGE
TOP
MAX.
20
R509
C510
8-10
Q504
R510
C511