SAA7151 Philips Semiconductors, SAA7151 Datasheet - Page 8

• Manufacturer Part Number: SAA7151
• Description: Digital multistandard colour decoder with SCART interface DMSD2-SCART
• Manufacturer: Philips Semiconductors

Philips Semiconductors
For matrixed RGB signals - the full screen SCART mode
and the fast insertion mode (blanking/switching) are
selectable. The chrominance stop filter is automatically
bypassed in full screen SCART mode.
Full screen RGB mode (SCART):
The CUV digital input signal (7-0) consists of
time-multiplexed samples for U and V. An offset correction
for both signals is applied to correct external clamping
Table 1 SCART interface control (Fig.3)
Fast insertion mode:
Fast insertion is applied by FSI pulse to ensure correct
timing. The RGB source signal is matrixed into UV and
inserted into the CVBS or Y/C source signal after two field
periods if FSI pulses are received. The output FSO is set
to HIGH during a determined insertion window (screen
plain minus 6 % of horizontal and vertical deflection).
Switch over depends on the phase of FSI in relation to the
valid pixel sequence depending on the phase-different
weighting factors. They are applied to the original and the
April 1993
RGB
only
Y/C or
CVBS
only
Fast
switch
RGB
only
Fast
switch
MODE
Digital multistandard colour decoder with
SCART interface (DMSD2-SCART)
FSO GPSW 2 GPSW 1 MUXC
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
CONNECTION
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
chroma
output of
TDA8446
to TDA8709A
high-Z
C
C
high-Z
C
8
errors. An internal timing correction compensates for slight
differences in timing during sampling. The U and V signals
are delay-compensated and fed to the output formatter.
The format 4:2:2 or 4:1:1 is generated by a switchable
filter.
The control signals for the front end (Figures 3 and 20)
MUXC, status bits FSST1, FSST0 (outputs GPSW2,
GPSW1) and FSO are generated by the SAA7151B.
inserted UV data (Figures 6 and 7)
The control signals for the front end (Table 1) MUXC, FSO,
status bits FSST1 and FSST0 (outputs GPSW2 and
GPSW1) are generated by the SAA7151B.
The amplitude of chrominance and colour-difference
signals are scaled down by factor 2 to avoid overloading of
the chrominance analog-to-digital converter. The
amplitudes are reduced in the TDA8446 by signals on lines
GPSW2 and GPSW1.
TDA8709A
selected
VIN2
VIN1
VIN2
VIN2
VIN2
input
CUV
(7-0)
U/V
C
0.5(C U)/
0.5(C V)
U/V
0.5(C U)/
0.5(C V)
luminance
fast switch
TDA8446
sync (RGB)
Y (Y/C) or CVBS
Y (Y/C) or CVBS
not used
Y (RGB)
not used
Y (RGB)
not used
Product specification
SAA7151B
input
selector (via
I
TDA8540
sync (RGB)
Y (Y/C) or
CVBS
Y (Y/C) or
CVBS
sync (RGB)
Y (Y/C) or
CVBS
2
C-bus)