
ADV7189B
Rev. B | Page 29 of 104
0
–10
–20
–30
–40
–50
–60
–70
010
8
6
4
212
04983-0-012
FREQUENCY (MHz)
COMBINED Y ANTIALIAS, S-VHS LOW-PASS FILTERS,
Y RESAMPLE
AM
P
L
IT
UDE
(dB)
Figure 12. Y S-VHS Combined Responses
The filter plots in
178H
Figure 12 show the S-VHS 1 (narrowest) to
S-VHS 18 (widest) shaping filter settings.
179H
Figure 14 shows the
PAL notch filter responses. The NTSC-compatible notches are
shown in
180H
Figure 15.
0
–20
–40
–60
–80
–100
–120
010
8
6
4
212
04983-0-013
FREQUENCY (MHz)
AM
PLITUDE
(dB)
COMBINED Y ANTIALIAS, CCIR MODE SHAPING FILTER,
Y RESAMPLE
Figure 13. Y S-VHS 18 Extra Wideband Filter (CCIR 601 Compliant)
0
–10
–20
–30
–40
–50
–60
–70
010
8
6
4
212
04983-0-015
FREQUENCY (MHz)
COMBINED Y ANTIALIAS, NTSC NOTCH FILTERS,
Y RESAMPLE
AM
P
L
IT
UDE
(dB)
Figure 14. PAL Notch Filter Response
0
–10
–20
–30
–40
–50
–60
–70
010
8
6
4
212
04983-0-015
FREQUENCY (MHz)
COMBINED Y ANTIALIAS, NTSC NOTCH FILTERS,
Y RESAMPLE
AM
PLI
T
UDE
(dB)
Figure 15 . NTSC Notch Filter Response
CHROMA FILTER
Data from the digital fine clamp block is processed by three sets
of filters. Note: the data format at this point is CVBS for CVBS
inputs, or chroma only for Y/C or Cr/Cb interleaved for YCrCb
input formats.
Chroma Antialias Filter (CAA). The ADV7189B over-
samples the CVBS by a factor of 2 and the Chroma/UV
by a factor of 4. A decimating filter (CAA) is used to
preserve the active video band and to remove any out-of-
band components. The CAA filter has a fixed response.
Chroma Shaping Filters (CSH). The shaping filter block
can be programmed to perform a variety of low-pass
responses. It can be used to selectively reduce the band-
width of the chroma signal for scaling or compression.
Digital Resampling Filter. This block is used to allow
dynamic resampling of the video signal to alter parameters
such as the time base of a line of video. Fundamentally, the
resampler is a set of low-pass filters. The actual response is
chosen by the system without user intervention.
The plots in
181H
Figure 16 show the overall response of all filters
together.