DDP3310B datasheet(9/60 Pages) MICRONAS

9 / 60 page

ADVANCE INFORMATION

DDP 3310B

Micronas

2.1.7. Chroma Interpolation

In case of YCrCb 4:1:1 input format, an interpolation fil-

ter is used which converts the digital input signal to

4:2:2 format. This filter runs with the incoming pixel

clock frequency.

The signal is passed to the scaler in YCrCb 4:2:2 for-

mat in order to convert the incoming pixel clock fre-

quency (27/32 MHz) to the internal frequency (40.5/

40 MHz). A linear phase interpolator is used to convert

the chroma sampling rate from 4:2:2 to 4:4:4.

The frequency response of the interpolator is shown in

Fig. 2–4. All further processing is carried out at the full

sampling rate.

2.1.8. Chroma Transient Improvement

The intention of this block is to enhance the chroma

resolution. A correction signal is calculated by differen-

tiation of the color difference signals. The differentia-

tion can be selected according to the signal bandwidth,

e.g. for PAL/NTSC/SECAM or digital component sig-

nals, respectively. The amplitude of the correction sig-

nal is adjustable. Small noise amplitudes in the correc-

tion signal are suppressed by an adjustable coring

circuit. To eliminate “wrong colors”, which are caused

by over and undershoots at the chroma transition, the

sharpened chroma signals are limited to a proper

value automatically.

2.1.9. Inverse Matrix and Digital RGB Processing

Six multipliers in parallel perform the matrix multiplica-

tion to transform the Cr and Cb signals to R−Y, B−Y,

and G

−Y. The initialization values for the matrix are

computed from the standard ITU-R (CCIR) matrix:

The multipliers are also used to adjust color saturation

and picture contrast. Since the multiplier allows

±4 as

the biggest coefficient, it is possible that the product of

CTM

×SATM×MxxM will be clipped, which causes

wrong colors. SATLIM limits the product of contrast

times saturation to allow a maximum oversaturation.

The matrix computes:

Fig. 2–4: Frequency response of the chroma 4:2:2 to

4:4:4 interpolation filter

Fig. 2–5: Digital color transient improvement

After adding the post-processed luma, the digital RGB

signals are limited to 10 bits. Three multipliers are

used to digitally adjust the white-drive and to imple-

ment an average beam current limiter. See also Sec-

tion 2.2.4. “CRT Measurement and Control”.

1,402

0,345

–

0,713

–

1 1,773

MHz

-10

-20

-30

-40

-50

Cr out

Cb out

Ampl.

CrCb

input

a) CrCb input of DTI

b) CrCb input + correction signal

c) sharpened and limited CrCb

MIN

CTM

-------------

SATM

----------------



 SATLIM

----------------------

------

MR1MMR2M

MG1MMG2M

MB1MMB2M

CTM

-------------





DDP3310B bảng dữ liệu(PDF) 9 Page - Micronas

DDP3310B bảng dữ liệu(HTML) 9 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

bảng dữ liệu tải về

Link URL