DDP3310B datasheet(8/60 Pages) MICRONAS

8 / 60 page

DDP 3310B

ADVANCE INFORMATION

Micronas

2.1.5. Soft Limiter

The dynamic range of the processed luma signal must

be limited to prevent the CRT from overload. An appro-

priate headroom for contrast, peaking, and brightness

can be adjusted by the TV manufacturer according to

the CRT characteristics. All signals above this limit will

be “soft”-clipped. A characteristic diagram of the soft

limiter is shown in Fig. 2–3. The total limiter consists of

three parts:

Part A includes adjustable tilt point and gain. The gain

before the tilt value is 1. Above the tilt value, a part

(0…15/16) of the input signal is subtracted from the

input signal itself. Therefore, the gain is adjustable

from 16/16 to 1/16, when the slope value varies from 0

to 15. The tilt value can be adjusted from 0 to 511.

Part B has the same characteristics as part A. The

subtracting part is also relative to the input signal, so

the total differential gain will become negative if the

sum of slope A and slope B is greater than 16 and the

input signal is above the both tilt values (see character-

istics).

Finally, the output signal of the soft limiter will be

clipped by a hard limiter adjustable from 256 to 511.

2.1.6. Chroma Input

The chroma input signal can either be YCrCb in 4:1:1

or in 4:2:2 format. For the digital signal processing, the

time-multiplexed chroma samples will be demulti-

plexed and synchronized with the signal at the HS pin.

The input formatter accepts either two’s complement

or binary offset code. Also, the delay can be adjusted

within a range of

±2 input clocks relative to the luma

signal; this doesn’t affect the chroma multiplex.

Fig. 2–3: Characteristics of soft limiter A and B and hard limiter

Table 2–2: 4:1:1 Chroma format

Pin Name

Pixel Number

Cb1

Cr1

Note: Cx

y; x = pixel number, y = bit number

Table 2–3: 4:2:2 Chroma format

Pin Name

Pixel Number

Cb1

Cr1

Cb3

Cr3

Cb1

Cr1

Cb3

Cr3

Cb1

Cr1

Cb3

Cr3

Cb1

Cr1

Cb3

Cr3

Cb1

Cr1

Cb3

Cr3

Cb1

Cr1

Cb3

Cr3

Cb1

Cr1

Cb3

Cr3

Cb1

Cr1

Cb3

Cr3

Note: Cx

y; x = pixel number, y = bit number

Output

Limiter Input

Slope A [0...15]

Slope B [0...15]

Part A

Part B

Hard limiter

Tilt A [ 0...511]

Tilt B [0...511]

Range= 256...511

511

1023

Calculation example for the soft-

limiter input amplitude.

Y Input

16...235 (ITU-R 601)

Contrast

Dig. Brightness 20

Peaking

off

Limiter input signal:

(Yin-black level)

×CTM/32‘+BRM

(235-16)

×63/32 + 20 = 451

Black Level

16 (constant)

100

200

300

400

500

600

700

800

900

100

200

300

400

DDP3310B Datasheet(PDF) 8 Page - Micronas

DDP3310B Datasheet(HTML) 8 Page - Micronas

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

Datasheet Download

Link URL