ADV7185KST Analog Devices Inc, ADV7185KST Datasheet - Page 11

• Manufacturer Part Number: ADV7185KST
• Description: IC VIDEO DECODER NTSC 80LQFP
• Manufacturer: Analog Devices Inc
• Type: Decoderr

Specifications of ADV7185KST

• Rohs Status: RoHS non-compliant
• Applications: DVD-RAM, Projectors, TV
• Mounting Type: Surface Mount
• Package / Case: 80-LQFP
• Adc/dac Resolution: 10b
• Screening Level: Commercial
• Package Type: LQFP
• Pin Count: 80
• Voltage - Supply, Analog: -
• Voltage - Supply, Digital: -
• Lead Free Status / RoHS Status: Not Compliant

LUMINANCE PROCESSING
Figure 7 shows the luminance data path. The 12-bit data from
the Y ADC is applied to an antialiasing low-pass filter that is
designed to band-limit the input video signal such that aliasing
does not occur. This filter dramatically reduces the design on an
external analog antialiasing filter; this filter need only remove
components in the input video signal above 22 MHz. The data
then passes through a shaping or notch filter.
When in CVBS mode, a notch filter must be used to remove the
unwanted chrominance data that lies around the subcarrier
frequency. A wide variety of programmable notch filters for
both PAL and NTSC are available. The YSFM[4:0] control the
selection of these filters; refer to Figures 8 and 9 for plots of
these filters. If S-video or component mode is selected a notch
filter is not required. The ADV7185 offers 18 possible shaping
filters (SVHS1-18) with a range of low-pass filter responses
from 0.5 MHz up to 5.75 MHz. The YSFM[4:0] control the
selection of these filters. Please refer to Figures 8 through 16 for
filter plots.
The next stage in the luminance processing path is a peaking
filter. This filter offers a sharpness function on the luminance
path. The degree of sharpness can be selected using YPM[2:0].
If no sharpness is required, this filter can be bypassed.
The luminance data is then passed through a resampler to correct
for line length variations in the input video. This resampler is
designed to always output 720 pixels per line for standard PAL or
NTSC. The resampler used on the ADV7185 is of very high quality
as it uses 128 phases to resample the video, giving 1/128 pixel
resolution. The resampler is controlled by a sync detection block
that calculates line length variations on the input video.
The final stage in the luminance path, before it is applied to an
output formatter block, is a 2-line delay store that is used to
compensate for delays in the chroma datapath when chroma
comb filter is selected.
REV. 0
ADC DATA
Figure 7. Luminance Processing Path
ALIASING
SHAPING
NOTCH
FILTER
ANTI-
AND
LPF
PEAKING
FILTER
DETECTION
RESAMPLE
STORES
DELAY
Y
SYNC
LINE
–11–
Figure 8. Luminance SVHS1–SVHS18 Shaping
Filter Responses
Figure 9. Luminance SVHS1–SVHS18 Shaping
Filter Responses (Close-Up)
Figure 10. Luminance NTSC Narrow/Wide Notch
Shaping Filter
–0.2
–0.4
–0.6
–0.8
–1.0
–10
–20
–30
–40
–50
–60
–10
–20
–30
–40
–50
–60
1.0
0.8
0.6
0.4
0.2
0
0
0
0
0
0
NTSC WN1
NTSC WN2
NTSC WN3
SVHS1
NTSC NN1
NTSC NN2
NTSC NN3
SVHS2
1
1
SVHS3
1
SVHS4
SVHS5
2
2
SVHS6
SVHS7
2
FREQUENCY – MHz
FREQUENCY – MHz
FREQUENCY – MHz
SVHS8
3
3
SVHS9
SVHS10
SVHS11
3
4
4
SVHS12
SVHS13
SVHS14
5
5
SVHS15
SVHS16
4
ADV7185
6
6
SVHS17
SVHS18
NTSC WN2
NTSC NN3
NTSC WN1
NTSC NN2
NTSC NN1
NTSC WN3
5
7
7
6
8
8