ADVANCE INFORMATION
VDP 313xY
2.14.2.2. Calculation of Vertical and East-West
Deflection Coefficients
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:
In Table 2–9 and Table 2–10 the formula for the calcu-
lation of the deflection initialization parameters from
the polynominal coefficients a,b,c,d,e is given for the
vertical and East-West deflection. Let the polynomial
be
a0 = (a · 128 – b · 1365.3 + c · 682.7 – d · 682.7) / 128
P : a + b(x – 0.5) + c(x – 0.5)2 + d(x – 0.5)3 + e(x – 0.5)4
Table 2–9: Calculation of Initialization values for
Table 2–10: Calculation of Initialization values for
Vertical Sawtooth
East-West Parabola
Vertical Deflection 50 Hz
East-West Deflection 50 Hz
a
b
c
d
a
b
c
d
e
a0 128
–1365.3
899.6
682.7
–904.3
296.4
–682.7
1363.4
–898.4
585.9
a0 128 –341.3 1365.3
–85.3
84.8
341.3
–454.5
898.3
–1171.7
756.5
a1
a2
a3
a1
a2
a3
a4
111.9
–899.6
586.8
–111.1
72.1
Vertical Deflection 60 Hz
a
b
c
d
East-West Deflection 60 Hz
a0 128
–1365.3
1083.5
682.7
–1090.2
429.9
–682.7
1645.5
–1305.8
1023.5
a
b
c
d
e
a1
a2
a3
a0 128 –341.3 1365.3
–85.3
341.3
a1
a2
a3
a4
134.6
–1083.5 102.2
–548.4
1305.5
–2046.6
1584.8
849.3
–161.2
125.6
Micronas
51
MICRONAS [ MICRONAS ]
