HMP8156 Intersil Corporation, HMP8156 Datasheet - Page 12

• Manufacturer Part Number: HMP8156
• Description: Ntsc/pal Encoder
• Manufacturer: Intersil Corporation

Video Processing
Upsampling
Video processing begins with the 4:4:4 sampled YCbCr data
from the input processor. After overlay mixing and optional
2X upscaling, the HMP8156 upsamples the 4:4:4 data to
generate 8:8:8 data. The encoder uses linear interpolation
for the upsampling.
Filtering
If enabled, the HMP8156 lowpass filters the Y data to
5.0MHz. Lowpass filtering Y removes any aliasing artifacts
due to the upsampling process, and simplifies the analog
output filters. The Y 5.0MHz lowpass filter response is
shown in Figure 13. At this point, the HMP8156 also scales
the Y data to generate the proper output levels for the vari-
ous video standards
The HMP8156 lowpass filters the Cb and Cr data to 1.3MHz
prior to modulation. The lowpass filtering removes any alias-
ing artifacts due to the upsampling process (simplifying the
analog output filters) and also properly bandwidth-limits Cb
and Cr prior to modulation. The chrominance filtering is not
optional like luminance filtering. The Cb and Cr 1.3MHz low-
pass filter response is shown in Figure 14.
FULL INPUT RESOLUTION, RECTANGULAR PIXELS
FULL INPUT RESOLUTION, SQUARE PIXELS
SIF INPUT RESOLUTION, RECTANGULAR PIXELS
SIF INPUT RESOLUTION, SQUARE PIXELS
VIDEO STANDARD
(B, D, G, H, I) PAL
(B, D, G, H, I) PAL
(B, D, G, H, I) PAL
(B, D, G, H, I) PAL
(M, NSM) NTSC
(M, NSM) NTSC
(M, NSM) NTSC
(M, NSM) NTSC
(CN) PA
(CN) PAL
(CN) PAL
(CN) PAL
(M) PAL
(M) PAL
(M) PAL
(M) PAL
(N) PAL
(N) PAL
(N) PAL
(N) PAL
L
TOTAL
PIXELS PER LINE
858
864
858
864
864
780
944
780
944
944
429
432
429
432
432
390
472
390
472
472
ACTIVE
TABLE 7. TYPICAL VIDEO TIMING PARAMETERS
720
720
720
720
720
640
768
640
784
768
352
352
352
352
352
320
384
320
392
384
HBLANK REGISTER VALUES
842 (0x34a)
853 (0x355)
842 (0x34a)
853 (0x355)
853 (0x355)
923 (0x39b)
923 (0x39b)
923 (0x39b)
834 (0x342)
845 (0x34d)
842 (0x34a)
853 (0x355)
853 (0x355)
923 (0x39b)
923 (0x39b)
923 (0x39b)
758 (0x2f6)
758 (0x2f6)
758 (0x2f6)
758 (0x2f6)
START
HMP8156
12
.
122 (0x7a)
133 (0x85)
122 (0x7a)
133 (0x85)
133 (0x85)
118 (0x76)
155 (0x9b)
118 (0x76)
155 (0x9b)
155 (0x9b)
130 (0x82)
141 (0x8d)
122 (0x7a)
133 (0x85)
133 (0x85)
118 (0x76)
155 (0x9b)
118 (0x76)
155 (0x9b)
155 (0x9b)
-10
-20
-30
-40
-50
-60
END
0
0
FIGURE 13. Y LOWPASS FILTER RESPONSE
PAL SQUARE PIXEL
CLK2 = 29.50MHz
NTSC OR PAL
RECTANGULAR PIXEL
CLK2 = 27.00MHz
NTSC SQUARE PIXEL
CLK2 = 24.54MHz
2
FIGURE 13A. FULL SPECTRUM
VBLANK REGISTER VALUES
259 (0x103)
310 (0x136)
259 (0x103)
309 (0x135)
310 (0x136)
259 (0x103)
310 (0x136)
259 (0x103)
309 (0x135)
310 (0x136)
259 (0x103)
310 (0x136)
259 (0x103)
309 (0x135)
310 (0x136)
259 (0x103)
310 (0x136)
259 (0x103)
309 (0x135)
310 (0x136)
START
4
FREQUENCY (MHz)
6
8
19 (0x13)
22 (0x16)
19 (0x13)
21 (0x15)
22 (0x16)
19 (0x13)
22 (0x16)
19 (0x13)
21 (0x15)
22 (0x16)
19 (0x13)
22 (0x16)
19 (0x13)
21 (0x15)
22 (0x16)
19 (0x13)
22 (0x16)
19 (0x13)
21 (0x15)
22 (0x16)
END
10
12
(MHZ)
CLK2
24.54
24.54
24.54
24.54
27.0
27.0
27.0
27.0
27.0
29.5
29.5
29.5
27.0
27.0
27.0
27.0
27.0
29.5
29.5
29.5
14