Datasheet

ADV7390/ADV7391/ADV7392/ADV7393 Data Sheet
Rev. J | Page 60 of 107
The gamma curves in Figure 71 and Figure 72 are examples
only; any user-defined curve in the range from 16 to 240 is
acceptable.
LOCATION
0
0
50
100
150
200
250
300
50 100 150 200 250
0.5
SIGNAL INPUT
GAMMA CORRECTED AMPLITUDE
SIGNAL OUTPUT
GAMMA CORRECTION BLOCK OUTPUT TO A RAMP INPUT
06234-072
Figure 71. Signal Input (Ramp) and Signal Output for Gamma 0.5
LOCATION
0
0
50
100
150
200
250
300
50 100 150 200 250
GAMMA CORRECTED AMPLITUDE
GAMMA CORRECTION BLOCK TO
A RAMP
INPUT FOR
VARIOUS GAMMA VALUES
0.3
0.5
1.5
1.8
SIGNAL INPUT
06234-073
Figure 72. Signal Input (Ramp) and Selectable Output Curves
ED/HD SHARPNESS FILTER AND ADAPTIVE FILTER
CONTROLS
Subaddress 0x40; Subaddress 0x58 to Subaddress 0x5D
There are three filter modes available on the ADV7390/ADV7391/
ADV7392/ADV7393: sharpness filter mode and two adaptive
filter modes.
ED/HD Sharpness Filter Mode
To enhance or attenuate the Y signal in the frequency ranges
shown in Figure 73, the ED/HD sharpness filter must be
enabled (Subaddress 0x31, Bit 7 = 1) and the ED/HD adaptive
filter must be disabled (Subaddress 0x35, Bit 7 = 0).
To select one of the 256 individual responses, the corresponding
gain values, ranging from −8 to +7 for each filter, must be
programmed into the ED/HD sharpness filter gain register at
Subaddress 0x40.
ED/HD Adaptive Filter Mode
In ED/HD adaptive filter mode, the following registers are used:
• ED/HD Adaptive Filter Threshold A
• ED/HD Adaptive Filter Threshold B
• ED/HD Adaptive Filter Threshold C
• ED/HD Adaptive Filter Gain 1
• ED/HD Adaptive Filter Gain 2
• ED/HD Adaptive Filter Gain 3
• ED/HD sharpness filter gain
To activate the adaptive filter control, the ED/HD sharpness
filter and the ED/HD adaptive filter must be enabled
(Subaddress 0x31, Bit 7 = 1, and Subaddress 0x35, Bit 7 = 1,
respectively).
The derivative of the incoming signal is compared to the three
programmable threshold values: ED/HD adaptive filter
(Threshold A, Threshold B, and Threshold C) registers
(Subaddress 0x5B, Subaddress 0x5C, and Subaddress 0x5D).
The recommended threshold range is 16 to 235, although any
value in the range of 0 to 255 can be used.
The edges can then be attenuated with the settings in the
ED/HD adaptive filter (Gain 1, Gain 2, and Gain 3) registers
(Subaddress 0x58, Subaddress 0x59 and Subaddress 0x5A), and
the ED/HD sharpness filter gain register (Subaddress 0x40).
There are two adaptive filter modes available. The mode is
selected using the ED/HD adaptive filter mode control
(Subaddress 0x35, Bit 6) as follows:
• Mode A is used when the ED/HD adaptive filter mode
control is set to 0. In this case, Filter B (LPF) is used in the
adaptive filter block. In addition, only the programmed
values for Gain B in the ED/HD sharpness filter gain
register and ED/HD adaptive filter (Gain 1, Gain 2, and
Gain 3) registers are applied when needed. The Gain A
values are fixed and cannot be changed.
• Mode B is used when ED/HD adaptive filter mode control is
set to 1. In this mode, a cascade of Filter A and Filter B is used.
Both settings for Gain A and Gain B in the ED/HD sharpness
filter gain register and ED/HD adaptive filter (Gain 1, Gain 2,
and Gain 3) registers become active when needed.
Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.