ADV7321 datasheet(55/88 Pages) AD

55 / 88 page

ADV7320/ADV7321

Rev. 0 | Page 55 of 88

HD SHARPNESS FILTER AND ADAPTIVE FILTER

CONTROLS

[Subaddresses 0x20, 0x38 to 0x3D]

There are three filter modes available on the ADV7320/

ADV7321: sharpness filter mode and two adaptive filter modes.

HD Sharpness Filter Mode

To enhance or attenuate the Y signal in the frequency ranges

shown in Figure 73, the HD sharpness filter must be enabled

and the HD adaptive filter enable must be disabled.

To select one of the 256 individual responses, the corresponding

gain values, which range from –8 to +7, for each filter must be

programmed into the HD sharpness filter gain register at

Address 0x20.

HD Adaptive Filter Mode

The HD adaptive filter threshold A, B, and C registers, the HD

adaptive filter gain 1, 2, and 3 registers, and the HD sharpness

gain register are used in adaptive filter mode. To activate the

adaptive filter control, the HD sharpness filter and the HD

adaptive filter must be enabled.

The derivative of the incoming signal is compared to the three

programmable threshold values: HD Adaptive Filter Threshold

A, B, and C. The recommended threshold range is from 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 HD

adaptive filter gain 1, 2, and 3 registers, and HD sharpness filter

gain register.

According to the settings of the HD adaptive filter mode

control, there are two adaptive filter modes available:

Mode A is used when adaptive filter mode is set to 0.

In this case, Filter B (LPF) will be used in the adaptive

filter block. Also, only the programmed values for

Gain B in the HD sharpness filter gain and HD

Adaptive Filter Gain 1, 2, and 3 are applied when

needed. The Gain A values are fixed and cannot be

changed.

Mode B is used when adaptive filter mode 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 HD

sharpness filter gain and HD Adaptive Filter Gain 1, 2,

and 3 become active when needed.

FREQUENCY (MHz)

FILTER A RESPONSE (Gain Ka)

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

FREQUENCY (MHz)

FILTER B RESPONSE (Gain Kb)

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

FREQUENCY (MHz)

1.0

1.1

1.2

1.3

1.4

1.5

1.6

INPUT

SIGNAL:

STEP

FREQUENCY RESPONSE IN SHARPNESS

FILTER MODE WITH Ka = 3 AND Kb = 7

SHARPNESS AND ADAPTIVE FILTER CONTROL BLOCK

Figure 73. Sharpness and Adaptive Filter Control Block

ADV7321 Datasheet(PDF) 55 Page - Analog Devices

ADV7321 Datasheet(HTML) 55 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88

Datasheet Download

Link URL