ADV7304A Datasheet, PDF (46/68 Pages) Analog Devices – Multiformat SD, Progressive Scan/HDTV Video Encoder with Six NSV 14-Bit DACs

ADV7304A/ADV7305A
a
d
b
e
c
f
Figure 64. HD Sharpness Filter Control with Different Gain Settings for HD Sharpness Filter Gain Value
HD Sharpness Filter and Adaptive Filter Application Examples
HD Sharpness Filter Application
The HD sharpness filter can be used to enhance or attenuate
the Y video output signal.
The register settings in Tables XIX and XX are used to achieve
the results shown in Figure 64. Input data was generated by an
external signal source.
Table XIX. Sharpness Filter on Frequency Sweep
Address
Register Setting
Reference*
00h
FCh
01h
10h
02h
20h
10h
00h
11h
81h
20h
00h
a
20h
08h
b
20h
04h
c
20h
40h
d
20h
80h
e
20h
22h
f
*See Figure 64.
The effect of the sharpness filter can also be seen when using the
internally generated crosshatch pattern.
Table XX. Sharpness Filter on Internal Test Pattern
Address
00h
01h
02h
10h
11h
20h
Register Setting
FCh
10h
20h
00h
85h
99h
In toggling the Sharpness Filter Enable Bit [Address 11h,
Bit 8], it can be seen that the line contours of the crosshatch
pattern change their sharpness.
Adaptive Filter Control Application
Figure 65 shows a typical signal to be processed by the adaptive
filter control block.
⌬: 692mV
@: 446mV
⌬: 332ns
@: 12.8ms
Figure 65. Input Signal to Adaptive Filter Control
⌬: 690mV
@: 446mV
⌬: 332ns
@: 12.8ms
Figure 66. Output Signal after Adaptive Filter Control
The register settings in Table XXI are used to obtain the results
shown in Figure 66, i.e., to remove the ringing on the Y signal.
Input data was generated by an external signal source.
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REV. A