
VCT 38xxA
ADVANCE INFORMATION
46
Micronas
2.15.1.2. Calculation of Vertical and East-West
Deflection Coefficients
In Table 2–8 the formula for the calculation of the
deflection initialization parameters from the polynomi-
nal coefficients a,b,c,d,e is given for the vertical and
East-West deflection. Let the polynomial be:
The initialization values for the accumulators a0..a3 for
vertical deflection and a0..a4 for East-West deflection
are 12-bit values. The coefficients that should be used
to calculate the initialization values for different field
frequencies are given below, the values must be
scaled by 128, i.e. the value for a0 of the 50 Hz vertical
deflection is:
FP Display Control Register, Vertical Sawtooth
h’110
DC offset of SAWTOOTH output
This offset is independent of EHT compensation.
0
OFS
h’11b
accu0 init value
1365
A0
h’11c
accu1 init value
900
A1
h’11d
accu2 init value
0
A2
h’11e
accu3 init value
0
A3
FP Display Control Register, East-West Parabola
h’12b
accu0 init value
1121
A0
h’12c
accu1 init value
219
A1
h’12d
accu2 init value
479
A2
h’12e
accu3 init value
1416
A3
h’12f
accu4 init value
1052
A4
Table 2–8:
Calculation of Initialization values for
Vertical Sawtooth and East-West Parabola
Vertical Deflection 50 Hz
a
b
c
d
a0
128
–1365.3
+682.7
–682.7
a1
899.6
–904.3
+1363.4
a2
296.4
–898.4
a3
585.9
P = a + b(x – 0.5) + c(x – 0.5)
2
+ d(x – 0.5)
3
+ e(x – 0.5)
4
a0 = (a · 128 – b · 1365.3 + c · 682.7 – d · 682.7) / 128
Vertical Deflection 60 Hz
a
b
c
d
a0
128
–1365.3
+682.7
–682.7
a1
1083.5
–1090.2
+1645.5
a2
429.9
–1305.8
a3
1023.5
East-West Deflection 50 Hz
a
b
c
d
e
a0
128
–341.3
1365.3
–85.3
341.3
a1
111.9
–899.6
84.8
–454.5
a2
586.8
–111.1
898.3
a3
72.1
–1171.7
a4
756.5
East-West Deflection 60 Hz
a
b
c
d
e
a0
128
–341.3
1365.3
–85.3
341.3
a1
134.6
–1083.5
102.2
–548.4
a2
849.3
–161.2
1305.5
a3
125.6
–2046.6
a4
1584.8