HMP8170 Datasheet, PDF (8/33 Pages) Intersil Corporation – NTSC/PAL Video Encoder

HMP8170, HMP8171, HMP8172, HMP8173
0
-10 ^{PAL SQUARE PIXEL}
CLK2 = 29.50MHz
-20
NTSC OR PAL
RECTANGULAR PIXEL
CLK2 = 27.00MHz
-30
NTSC SQUARE PIXEL
CLK2 = 24.54MHz
-40
-50
0
-0.5
PAL SQUARE PIXEL
CLK2 = 29.50MHz
-1.0
NTSC OR PAL
-1.5
RECTANGULAR PIXEL
CLK2 = 27.00MHz
-2.0
NTSC SQUARE PIXEL
CLK2 = 24.54MHz
-2.5
-60
0
.
0
-10
-20
-30
-40
-50
-60
0
2
4
6
8
10
12
14
FREQUENCY (MHz)
-3.0
0
1
2
3
4
5
6
7
FREQUENCY (MHz)
FIGURE 7A. FULL SPECTRUM
FIGURE 7B. PASS BAND
FIGURE 7. Y LOWPASS FILTER RESPONSE
PAL SQUARE PIXEL
CLK2 = 29.50MHz
NTSC OR PAL
RECTANGULAR PIXEL
CLK2 = 27.00MHz
NTSC SQUARE PIXEL
CLK2 = 24.54MHz
0
-0.5
-1.0
PAL SQUARE PIXEL
CLK2 = 29.50MHz
-1.5
-2.0
NTSC OR PAL
RECTANGULAR PIXEL
-2.5
CLK2 = 27.00MHz
-3.0
NTSC SQUARE PIXEL
CLK2 = 24.54MHz
-3.5
2
4
6
8
10
12
FREQUENCY (MHz)
-4.0
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
FREQUENCY (MHz)
FIGURE 8A. FULL SPECTRUM
FIGURE 8B. PASS BAND
FIGURE 8. Cb AND Cr LOWPASS FILTER RESPONSE
Color Subcarrier Generation
The HMP817x uses a numerically controlled oscillator
(NCO) clocked by CLK2 and a sine look up ROM to generate
the color subcarrier. As shown in Figure 9, the phase
increment value (PHINC) of the NCO may come from the
encoder’s internal look up table, BT.656 ancillary data, or a
control register. The PHINC source is selected in timing I/O
register 2.
.
INTERNAL
BT.656
I²C
+ ^PHINC
D
Q
PHINT
CLK2
PHINC
SELECT
NCO RESET
FIGURE 9. COLOR SUBCARRIER GENERATION NCO.
8