SAA7121H/V2,557 Trident Microsystems, Inc., SAA7121H/V2,557 Datasheet - Page 7

• Manufacturer Part Number: SAA7121H/V2,557
• Manufacturer: Trident Microsystems, Inc.

Specifications of SAA7121H/V2,557

• Lead Free Status / RoHS Status: Supplier Unconfirmed

Philips Semiconductors
7
The digital video encoder encodes digital luminance and
colour difference signals into analog CVBS and
simultaneously S-video signals. NTSC-M, PAL-B/G and
sub-standards are supported. Both interlaced and
non-interlaced operation is possible for all standards.
The basic encoder function consists of subcarrier
generation, colour modulation and insertion of
synchronization signals. Luminance and chrominance
signals are filtered in accordance with the standard
requirements of “RS-170-A” and “CCIR 624” .
For ease of analog post filtering the signals are twice
oversampled with respect to the pixel clock before
digital-to-analog conversion.
The total filter transfer characteristics are illustrated in
Figs 3 to 6. The DACs for Y, C and CVBS are realized with
full 10-bit resolution.
The 8-bit multiplexed C
(D1 format) compatible, but the SAV and EAV codes can
be decoded optionally, when the device is operated in
slave mode.
It is also possible to connect a Philips digital video decoder
(SAA7111 or SAA7151B) to this encoder. By connecting
pin RTCI to pin RTCO of a decoder, information about the
actual subcarrier, PAL-ID and (with SAA7111 and newer
types) definite subcarrier phase can be inserted.
The digital video encoder synthesizes all necessary
internal signals, colour subcarrier frequency and
synchronization signals from that clock.
Wide screen signalling data can be loaded via the I
and is inserted into line 23 for standards using 50 Hz field
rate.
The IC also contains closed caption and extended data
services encoding (line 21), and supports anti-taping
signal generation in accordance with Macrovision.
A number of possibilities are provided for setting different
video parameters, such as:
During reset (RESET = LOW) and after reset is released,
all digital I/O stages are set to input mode. A reset forces
the I
sets register 3A to 03H, register 61 to 06H, registers 6BH
and 6EH to 00H and bit TTX60 to 0. No other control
registers are influenced by a reset.
2002 Oct 11
Black and blanking level control
Colour subcarrier frequency
Variable burst amplitude, etc.
Digital video encoder
FUNCTIONAL DESCRIPTION
2
C-bus interface to abort any running bus transfer and
B
-Y-C
R
formats are “CCIR 656”
2
C-bus
7
7.1
Real-time arbitration on the data stream to be encoded is
performed in the data manager.
A pre-defined colour look-up table located in this block can
be read out in a pre-defined sequence (8 steps per active
video line), achieving a colour bar test pattern generator
without the need for an external data source. The colour
bar function is under software control only.
7.2
7.2.1
The encoder generates out of Y, U and V baseband
signals luminance and colour subcarrier output signals,
suitable for use as CVBS or separate Y and C signals.
Luminance is modified in gain and in offset (latter
programmable in a certain range to enable different black
level set-ups). A blanking level can be set after insertion of
a fixed synchronization pulse tip level in accordance with
standard composite synchronization schemes. Other
manipulations used for the Macrovision anti-taping
process such as additional insertion of AGC super-white
pulses (programmable in height) are supported by the
SAA7120H only.
In order to enable easy analog post filtering, luminance is
interpolated from a 13.5 MHz data rate to a 27 MHz data
rate, providing luminance in 10-bit resolution. This filter is
also used to define smoothed transients for
synchronization pulses and blanking period. The transfer
characteristics of the luminance interpolation filter are
illustrated in Figs 5 and 6.
Chrominance is modified in gain (programmable
separately for U and V), standard dependent burst is
inserted, before baseband colour signals are interpolated
from a 6.75 MHz data rate to a 27 MHz data rate. One of
the interpolation stages can be bypassed, thus providing a
higher colour bandwidth, which can be made use of for
Y and C output. The transfer characteristics of the
chrominance interpolation filter are illustrated in
Figs 3 and 4.
The amplitude, beginning and ending of the inserted burst,
is programmable in a certain range that is suitable for
standard signals and for special effects. Behind the
succeeding quadrature modulator, colour in a 10-bit
resolution is provided on the subcarrier.
The numeric ratio between Y and C outputs is in
accordance with the respective standards.
Data manager
Encoder
V
IDEO PATH
SAA7120H; SAA7121H
Product specification