VPC3240D Просмотр технического описания (PDF) - Micronas

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VPC3240D

Comb Filter Video Processor

Micronas 

VPC 323xD, VPC 324xD

ADVANCE INFORMATION

Table 2–7: Output signals corresponding to the different formats

Format

16 bit

YCrCb422

8 bit

YCrCb422

ITU-R 656

dblclk

0

1

1

enable656 HSync

0

PAL/NTSC

0

PAL/NTSC

1

not used

VSync

PAL/NTSC

PAL/NTSC

not used

AVO

Y-Data

marks active 4:2:2

pixels

marks active 4:2:2

pixels

not used

ITU-R 656

C-Data

4:2:2

tristated

tristated

The multiplex of luminance and chrominance informa-

tion and the embedding of 656-headers can be

enabled independently. An overview of the resulting

output formats and the corresponding signals is given

in Table 2–7.

2.9.7. Output Code Levels

Output Code Levels correspond to ITU-R code levels:

Y = 16...240

Black Level = 16

CrCb = 128±112

An overview over the output code levels is given in

Table 2–8.

2.9.8. Output Ports

All data and sync pins operate at TTL compliant levels

and can be tristated via I2C registers.

Additionally, the data outputs can be tristated via the

YCOE output enable pin immediately. This function

allows the digital insertion of a 2nd digital video source

(e. g. MPEG aso.).

To minimize crosstalk data and clock pins automati-

cally adopt the output driver strength depending on

their specific external load (max. 50pF). Sync and Fifo

control pins have to be adjusted manually via an I2C

register.

2.9.9. Test Pattern Generator

The YCrCb outputs can be switched to a test mode

where YCrCb data are generated digitally in the

VPC32xx. Test patterns include luma/chroma ramps,

flat field and a pseudo color bar.

2.10. PAL+ Support

For PAL+, the VPC 323xD provides basic helper pre-

processing:

– A/D conversion (shared with the existing ADCs)

– mixing with subcarrier frequency

– lowpass filter 2.5 MHz

– gain control by chroma ACC

– delay compensation to composite video path

– output at the luma output port

Helper signals are processed like the main video luma

signals, i.e. they are subject to scaling, sample rate

conversion and orthogonalization if activated. The

adaptive comb filter processing is switched off for the

helper lines.

It is expected that further helper processing (e.g. non-

linear expansion, matched filter) is performed outside

the VPC.

2.10.1. Output Signals for PAL+/Color+ Support

For a PAL+/Color+ signal, the 625 line PAL image con-

tains a 16/9 core picture of 431 lines which is in stan-

dard PAL format. The upper and lower 72 lines contain

the PAL+ helper signal, and line 23 contains signalling

information for the PAL+ transmission.

For PAL+ mode, the Y signal of the core picture, which

is during lines 60–274 and 372–586, is replaced by the

orthogonal composite video input signal. In order to fit

the signal to the 8-bit port width, the ADC signal ampli-

tudes are used. During the helper window, which is in

lines 24–59, 275–310, 336–371, 587–622, the demodu-

lated helper is signal processed by the horizontal scaler

and the output circuitry. It is available at the luma output

port. The processing in the helper reference lines 23

and 623 is different for the wide screen signaling part

and the black reference and helper burst signals. The

code levels are given in detail in Table 2–8, the output

signal for the helper reference line is shown in Fig. 2–17.

20

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