VDP 31xxB
PRELIMINARY DATA SHEET
3.2.2. Calculation of Vertical and East-West
Deflection Coefficients
In Table 3–6 the formula for the calculation of the deflec-
tion initialization parameters from the polynomial coeffi-
cients a,b,c,d,e is given for the vertical and East-West
deflection. Let the polynomial be
P : a ) b(x * 0.5) ) c(x * 0.5)2 ) d(x * 0.5)3 ) e(x * 0.5)4
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 fre-
quencies are given below, the values must be scaled by
128, i.e. the value for a0 of the 50 Hz vertical deflection
is
a0 + (a * 128 * b * 1365.3 ) c * 682.7 * d * 682.7)ń128
Table 3–6: Tables for the Calculation of Initialization values for Vertical Sawtooth and East-West Parabola
Vertical Deflection 50 Hz
East-West Deflection 50 Hz
a
128
b
c
d
a
b
c
d
e
a0
a1
a2
a3
–1365.3
899.6
+682.7
–904.3
296.4
–682.7
+1363.4
898.4
585.9
a0
a1
a2
a3
a4
128
–341.3
111.9
1365.3
–899.6
586.8
–85.3
84.8
341.3
–454.5
898.3
–111.1
72.1 –1171.7
Vertical Deflection 60 Hz
756.5
a
128
b
c
d
East-West Deflection 60 Hz
a0
a1
a2
a3
–1365.3
1083.5
+682.7
–1090.2
429.9
–682.7
+1645.5
–1305.8
1023.5
a
b
c
d
e
a0
a1
a2
a3
a4
128
–341.3
1365.3
–85.3
102.2
–161.2
341.3
–548.4
1305.5
134.6 –1083.5
849.3
125.6 –2046.6
1584.8
46
Micronas
MICRONAS [ MICRONAS ]
