ADVANCE INFORMATION
VPC 323xD, VPC 324xD
3.2.1. Calculation of Vertical and East-West
Deflection Coefficients
3.2.2. Scaler Adjustment
In case of linear scaling, most of the scaler registers
need not be set. Only the scaler mode, active video
length, and the fixed scaler increments (scinc1/scinc2)
must be written.
In Table 3–4 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 adjustment of the scaler for nonlinear scaling
modes should use the parameters given in table 3–5.
An example for ‘panorama vision’ mode with 13.5 MHz
line-locked clock is depicted in Fig. 3–2. The figure
shows the scaling of the input signal and the variation
of the scaling factor during the active video line. The
scaling factor starts below 1, i.e. for the borders the
video data is expanded by scaler 2. The scaling factor
becomes one and compression scaling is done by
scaler 1. When the picture center is reached, the scal-
ing factor is held constant. At the second border the
scaler increment is inverted and the scaling factor
changes back symmetrically. The picture indicates the
function of the scaler increments and the scaler win-
dow parameters. The correct adjustment requires that
pixel counts for the respective windows are always in
number of output samples of scaler 1 or 2.
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
frequencies 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) ÷ 128
Table 3–4: Tables for the Calculation of Initialization values for Vertical Sawtooth and East-West Parabola
Vertical Deflection 50 Hz East-West Deflection 50 Hz
a
b
c
d
e
a
b
c
d
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
–1171.7
756.5
a0
a1
a2
a3
128
–1365.3
899.6
+682.7
–904.3
296.4
–682.7
+1363.4
–898.4
585.9
–111.1
72.1
Vertical Deflection 60 Hz
East-West Deflection 60 Hz
a
b
c
d
a
b
c
d
e
a0
a1
a2
a3
128
–1365.3
1083.5
+682.7
–1090.2
429.9
–682.7
+1645.5
–1305.8
1023.5
a0
a1
a2
a3
a4
128
–341.3
134.6
1365.3
–1083.5
849.3
–85.3
102.2
–161.2
125.6
341.3
–548.4
1305.5
–2046.6
1584.8
Micronas
49
MICRONAS [ MICRONAS ]
