The ADV7174/ADV7179 is an integrated digital video encoder
that converts digital CCIR-601 4:2:2 8-bit component video data
into a standard analog baseband television signal compatible
with worldwide standards.
The on-board SSAF (super sub-alias filter) with extended
luminance frequency response and sharp stop-band attenuation
enables studio quality video playback on modern TVs, giving
optimal horizontal line resolution.
An advanced power management circuit enables optimal con-
trol of power consumption in both normal operating modes
and in power-down or sleep modes.
The ADV7174/ADV7179 supports both PAL and NTSC square
pixel operation. The parts incorporate WSS and CGMS-A data
The output video frames are synchronized with the incoming
data timing reference codes. Optionally, the encoder accepts
(and can generate) HSYNC, VSYNC, and FIELD timing signals.
These timing signals can be adjusted to change pulse width and
position while the part is in the master mode. The encoder
requires a signal two times the pixel rate (27 MHz) clock for
standard operation. Alternatively, the encoder requires a
24.5454 MHz clock for NTSC or 29.5 MHz clock for PAL
square pixel mode operation. All internal timing is generated
A separate Teletext port enables the user to directly input
Teletext data during the vertical blanking interval.
The ADV7174/ADV7179 modes are set up over a 2-wire serial
bidirectional port (I2 C compatible) with two slave addresses.
The ADV7174/ADV7179 is packaged in a 40-lead 6 mm × 6 mm
DATA PATH DESCRIPTION
For PAL B/D/G/H/I/M/N and NTSC M and N modes, YCrCb
4:2:2 data is input via the CCIR-656 compatible pixel port at a
27 MHz data rate. The pixel data is demultiplexed to form three
data paths. Y typically has a range of 16 to 235, and Cr and Cb
typically have a range of 128 ± 112; however, it is possible to
input data from 1 to 254 on both Y, Cb, and Cr. The ADV7174/
ADV7179 supports PAL (B/D/G/H/I/M/N) and NTSC (with
and without pedestal) standards. The appropriate SYNC, BLANK,
and burst levels are added to the YCrCb data. Macrovision Anti-
taping (ADV7174 only), closed-captioning, and Teletext levels
are also added to Y and the resultant data is interpolated to a
rate of 27 MHz. The interpolated data is filtered and scaled by
three digital FIR filters.
The U and V signals are modulated by the appropriate subcarrier
sine/cosine phases and added together to make up the chromi-
nance signal. The luma (Y) signal can be delayed 1–3 luma
cycles (each cycle is 74 ns) with respect to the chroma signal.
The luma and chroma signals are then added together to make
up the composite video signal. All edges are slew rate limited.
The YCrCb data is also used to generate RGB data with
appropriate SYNC and BLANK levels. The RGB data is in
synchronization with the composite video output. Alternatively,
analog YPbPr data can be generated instead of RGB data.
The three l0-bit DACs can be used to output:
• Composite Video + Composite Video
• S-Video + Composite Video
• YPrPb Video
• SCART RGB Video
Alternatively, each DAC can be individually powered off if not
Video output levels are illustrated in Appendix 6.
INTERNAL FILTER RESPONSE
The Y filter supports several different frequency responses,
including two low-pass responses, two notch responses, an
extended (SSAF) response, a CIF response, and a QCIF
response. The UV filter supports several different frequency
responses, including four low-pass responses, a CIF response,
and a QCIF response. These can be seen in Table 7 and Table 8
and Figure 6 to Figure 18.
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