AD722JR-16 Analog Devices, AD722JR-16 Datasheet

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AD722JR-16

Manufacturer Part Number
AD722JR-16
Description
RGB to NTSC/PAL Encoder
Manufacturer
Analog Devices
Datasheet

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a
PRODUCT DESCRIPTION
The AD722 is a low cost RGB to NTSC/PAL Encoder that
converts red, green and blue color component signals into their
corresponding luminance (baseband amplitude) and chromi-
nance (subcarrier amplitude and phase) signals in accordance
with either NTSC or PAL standards. These two outputs are
also combined to provide composite video output. All three out-
puts can simultaneously drive 75 , reverse-terminated cables.
All logical inputs are CMOS compatible. The chip operates
from a single +5 V supply. No external delay lines or filters are
required. The AD722 may be powered down when not in use.
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
NTSC/PAL
FEATURES
Low Cost, Integrated Solution
+5 V Operation
Accepts FSC Clock or Crystal, or 4FSC Clock
Composite Video and Separate Y/C (S-Video) Outputs
Minimal External Components:
Phase Lock to External Subcarrier
Drives 75
Logic Selectable NTSC or PAL Encoding Modes
Compact 16-Pin SOIC
APPLICATIONS
RGB to NTSC or PAL Encoding
CARRIER
HSYNC
VSYNC
No External Filters or Delay Lines Required
Onboard DC Restoration
Accepts Either HSYNC & VSYNC or CSYNC
SUB-
4FSC
FSC
GREEN
BLUE
RED
Reverse-Terminated Loads
4FSC
4FSC
XNOR
XNOR
CLAMP
CLAMP
CLAMP
DC
DC
DC
CSYNC
QUADRATURE
DECODER
SEPARATOR
+4
SYNC
XOSC
XOSC
RGB-TO-YUV
ENCODING
MATRIX
BURST
DETECTOR
PHASE
FSC
FSC 90
FSC 0
Y
U
V
BURST
CHARGE
CHARGE
LP PRE-
3-POLE
4-POLE
4-POLE
FILTER
PUMP
PUMP
LPF
LPF
FUNCTIONAL BLOCK DIAGRAM
(PAL ONLY)
NTSC/PAL
CLAMP
CLAMP
180
FILTER
FILTER
U
V
LOOP
LOOP
CSYNC
SC 90 /270
The AD722 accepts either FSC or 4FSC clock. When a clock is
not available, a low cost parallel-resonant crystal (3.58 MHz
(NTSC) or 4.43 MHz (PAL)) and the AD722’s on-chip oscilla-
tor generate the necessary subcarrier clock. The AD722 also ac-
cepts the subcarrier clock from an external video source.
The interface to VGA Controllers and MPEG Video Decoders
is simple: an on-chip logic “XNOR” accepts the available verti-
cal (VSYNC) and horizontal sync (HSYNC) signals and creates
the composite sync (CSYNC) signal on-chip. If available, the
AD722 will also accept a standard CSYNC signal by connecting
VSYNC to +5 V and applying CSYNC to HSYNC pin. The
AD722 contains decoding logic to identify valid HSYNC pulses
for correct burst insertion.
Delays in the U and V chroma filters are matched by an on-chip
sampled-data delay line in the Y signal path. To prevent
aliasing, a prefilter at 5 MHz is included ahead of the delay line
and a post-filter at 5 MHz is added after the delay line to sup-
press harmonics in the output. These low-pass filters are opti-
mized for minimum pulse overshoot. The overall luma delay,
relative to chroma, has been designed to be 170 ns, which
precompensates for delays in the filters used in the IF section of
a television receiver. This precompensation delay is already
present in TV broadcasts. The AD722 comes in a space-saving
SOIC and is specified for the 0 C to +70 C commercial tem-
perature range.
One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A.
Tel: 617/329-4700
4FSC
4FSC
VCO
VCO
MODULATORS
INSERTION
BALANCED
CSYNC
RGB to NTSC/PAL Encoder
NTSC/PAL
SAMPLED-
DELAY
DATA
LINE
AT 4FSC
CLOCK
3.6MHz (NTSC)
4.4MHz (PAL)
3-POLE LPF
NTSC/PAL
LP POST-
2-POLE
FILTER
© Analog Devices, Inc., 1995
X2
X2
X2
AD722
Fax: 617/326-8703
COMPOSITE
OUTPUT
LUMINANCE
OUTPUT
CHROMINANCE
OUTPUT

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AD722JR-16 Summary of contents

Page 1

... BLUE DC CLAMP REV. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. ...

Page 2

AD722–SPECIFICATIONS Parameter SIGNAL INPUTS (RDIN, GRIN, BLIN) Input Amplitude Black Level 1 Input Resistance Input Capacitance LOGIC INPUTS (SYNC, FSC, ENCD, NTSC) Logic LO Input Voltage Logic HI Input Voltage Logic LO Input Current (DC) Logic HI Input Current (DC) ...

Page 3

... C to +70 C 16-Pin SOIC R-16 AD722JR-16-Reel +70 C 16-Pin SOIC R-16 AD722JR-16-Reel7 +70 C 16-Pin SOIC R-16 CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD722 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges ...

Page 4

AD722 Pin Mnemonic 1 STND 2 AGND 3 FIN 4 APOS 5 ENCD 6 RIN 7 GIN 8 BIN 9 CRMA 10 COMP 11 LUMA 12 SELECT 13 DGND 14 DPOS 15 VSYNC 16 HSYNC *The Luminance, Chrominance, and Composite ...

Page 5

COMPOSITE SYNC TEKTRONIX AD722 TSG 300 COMPONENT RGB TO VIDEO NTSC/PAL 75 RGB WAVEFORM ENCODER GENERATOR 3 GENLOCK TEKTRONIX 1910 FSC COMPOSITE VIDEO WAVEFORM GENERATOR Figure 1. Evaluation Setup 0.10 APL = 49.5% 525 LINE NTSC NO FILTERING SLOW CLAMP ...

Page 6

AD722–Typical Characteristics Figure 7. 100% Color Bars on Vector Scope, PAL 0.10 APL = 11.6% 525 LINE NTSC NO FILTERING SLOW CLAMP TO 0.00V @ 6.63µs 0.5 0.0 PRECISION MODE OFF SYNCHRONOUS SYNC = SOURCE FRAMES SELECTED : 1 2 ...

Page 7

H TIMING MEASUREMENT RS–170A (NTSC) FIELD = 1 LINE = 22 9.72µs 9.0 CYCLES 5.49µs 4.59µs 100ns 39.7 IRE 124ns AVERAGE 256 256 Figure 12. Horizontal Timing, NTSC PHASE DETECTOR FSC SUB- XOSC XOSC CARRIER 4FSC 4FSC SYNC NTSC/PAL SEPARATOR ...

Page 8

AD722 The other analog path is the chrominance path which is where the U and V color difference signals are processed. The U and V signals first pass through 4-pole modified Bessel low-pass filters with –3 dB frequencies of 1.2 ...

Page 9

Basically these two standards use most of the features of the standard that their names imply, but use the subcarrier that is equal to or approximately equal to the frequency of the other standard. Because of the automatic programming of ...

Page 10

AD722 + 0.1µF AA COMP V 24 REF FS DATA IN ADJ ADV7120 + 10k SYNC IOR MPEG CLOCK IOG DECODER BLANK IOB GND HSYNC VSYNC * PARALLEL–RESONANT CRYSTAL; 3.579545MHz (NTSC) OR 4.433620MHz ...

Page 11

... In addition these chips rescale the output from the computer to fit correctly on the screen of a television. A list of known devices is available through Analog Devices’ Applications group, but the most complete and current information will be available from the manufacturers of graphics controller ICs. ...

Page 12

AD722 Synchronous vs. Asynchronous Operation The source of RGB video and synchronization used as an input to the AD722 in some systems is derived from the same clock signal as used for the AD722 subcarrier input (FIN). These systems are ...

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