ML6461 Datasheet, PDF (1/30 Pages) Micro Linear Corporation – CCIR656 NTSC Video Encoder

February 1999
PRELIMINARY
ML6461
CCIR656 NTSC Video Encoder
GENERAL DESCRIPTION
The ML6461 is a multi-standard CCIR656 (4:2:2) video
(input) composite and S-video (outputs) encoder for NTSC
systems. It is designed to provide a low cost, single-chip
output interface for a variety of video applications
including set-top decoders, DVD players, and other YCrCb
to Y/C equipment.
The ML6461 accepts 8-bit YCrCb video in either CCIR656
or Square Pixel format and generates analog Y, C and CV
waveforms complete with Closed Caption encoding.
The ML6461 includes output analog reconstruction filters,
phase equalizer, and 6dB (2X gain) drivers. Gain scaling,
sync, and Y+C mixing are performed at the output of the
relevant 10-bit DAC, eliminating the gain mapping stages
that require additional DAC bits. The result is Y SNR and
granularity remain precisely the same as the source.
The ML6461 supports both master and slave timing
operations. S-Video and multiple composite signals can be
driven simultaneously into 75Ω loads.
FEATURES
s Closed Caption VBI encoder for line 21 and 284
s Handles SAV/EAV codes for CCIR656 Video
s Single clock input: 27MHz CCIR656, 24.54MHz Sq. Pix.
s Color subcarrier correction for overlay applications
s Onboard analog 7th-order reconstruction filters and
6dB drivers with differential gain/phase of 0.5%/0.5º
s Y, C, CV outputs drive both AC or DC coupled loads
s Multiple 75Ω line drivers for two composite outputs,
channel modulator, and S-Video
s 2-wire serial control bus, or selectable presets for stand-
alone operation
s Handles Japanese NTSC signals
BLOCK DIAGRAM
YCRCB0
21
YCRCB1
20
YCRCB2
19
YCRCB3
18
YCRCB4
17
YCRCB5
13
YCRCB6
12
YCRCB7
11
7
DVCC1
8
DGNDI
LUMA
BLANKING
DELAY
COMPEN-
SATION
TIMING
GENERATOR
(SAV/EAV)
14
15
DVCC2
DGND2
UP
SAMPLER
LUMA
RECONSTRUCTION
FILTER
(FIR)
CLOSED
CAPTIONING
1
AVCC1
10 BIT
YDAC
NEGATIVE
SYNC DAC
POSITIVE
SYNC DAC
2
AGND1
7th ORDER
ANALOG
FILTER
WITH
GROUP DELAY
EQUALIZATION
25 24
AVCC2
AGND2
+_Σ
+
YOUT
6dB
27
CVOUT
6dB
26
COUT
6dB
28
REFERENCE
GENERATOR
7th ORDER
ANALOG
FILTER
WITH
GROUP DELAY
EQUALIZATION
CLK
16
VSYNC
9
HSYNC
10
FIELD
5
SCLK
22
SDATA
23
CHROMA
BLANKING
BURST
INSERTION
SERIAL
INTERFACE
OVERLAY
INTERFACE
COLOR
SPACE
CONVERTER
UP
SAMPLER
CHROMA
BANDLIMIT
FILTER
MULTIPLYING
ACCUMULATOR
PHASE
ACCUMULATOR
SUBCARRIER
GENERATION
Σ
CHROMA
RECONSTRUCTION
FILTER
(FIR)
CDAC
8
PRESET1 PRESET0
4
3
PHERR
6
1