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Circuit Descriptions, Abbreviation List, and IC Data Sheets
9.4
Front-End
This chassis uses different tuners depending on the region. An
overview of region-dependency can be found in table "Tuner
diversity".
Table 9-1 Tuner diversity
Region
Tuner
Europe
TD1316AF
UV1318S
AP
UV1316E
China
TEDE9
Latam
UV1338
The TD1316AF hybrid tuner used, is capable of receiving both
analogue and digital (DVB-T) signals. For the application in this
chassis see figure "Tuner IF diagram".
Tuner
Supply
Digital IF
+5V/+33V
36.16MHz
4MHz
IF AGC
Figure 9-4 Tuner IF diagram
While receiving analogue signals, the signal coming from the
tuner is fed to the IF demodulator (through the SAW filters) and
then passed to the Trident Video Processor.
While receiving digital signals, the signal coming from the tuner
is fed to the channel decoder, to the MPEG decoder and then
to the Trident Video Processor.
9.4.1
Video IF Amplifier
The IF-filter is integrated in a SAW (Surface Acoustic Wave)
filter. One for filtering IF-video (item 1102) and one for IF-audio
(item 1103). The type of these filters depends on the standard
to be received (region-dependency). Some filters can be
switched to another standard, what makes them suitable for
applications in multi-standard platforms. An overview of the
SAW filter diversity can be found in table "SAW filter diversity".
Table 9-2 SAW filter diversity
SAW filter
Switching Y/N
OFWK3953M
No
OFWK9656M
Yes
OFWK7265L
Yes
OFWK9361L
No
OFWK3956L
No
OFWK3955L
No
OFWK9352L
No
OFWM1967L
No
Switching is done by the microcontroller via SAW_SW. In table
"SAW filter switching" is explained how to address the different
system standards.
Table 9-3 SAW filter switching
Region
SAW_SW
Europe
1
0
Type
Hybrid
analogue
analogue
analogue
analogue
Video
CVBS
SAW filter
IF Demodulator
2
nd
SIF
Audio
SAW filter
RF AGC_analogue
RFAGC
RF AGC_digital
I 2 C_analogue
Switch IC
I 2 C
I 2 C_digital
G_16860_054.eps
Region
Video/Audio
Europe
Video
Europe
Audio
AP
Video
AP
Sound
China
Video
China
Video
China
Audio
LATAM
Video/Audio
System
L'
other systems
Region
AP
China
LATAM
The hybrid tuner TDA1316AF, used in Europe sets, needs to
be switched between digital and analogue mode. This is done
by the microcontroller via DVB_SW. Refer to table "Hybrid
tuner digital/analogue switching" for details.
Table 9-4 Hybrid tuner digital/analogue switching
Region
Europe
The pin assignment of all analogue tuners is equal and can be
found in table "Pin assignment analogue tuners".
Table 9-5 Pin assignment analogue tuners
Pin number Description
1
2
3
4
5
020207
6
7
8
9
10
11
The pin assignment of the hybrid tuner can be found in table
"Pin assignment hybrid tuner".
Table 9-6 Pin assignment hybrid tuner
Pin number Description
1
2
3
4
5
6
7
8
9
10
11
9.4.2
Automatic Gain Control
In the LC7.2x chassis (digital sets), the automatic gain control
depends on if the set is receiving a digital or an analogue
signal. During analogue reception, the hybrid tuner receives an
external AGC voltage, coming from the demodulator, to
perform automatic gain control. During digital reception, no
external AGC voltage is used but the tuners internal AGC loop
is used.
In the LC7.1x chassis (analogue sets), the tuner receives an
external AGC voltage, coming from the demodulator, to
perform automatic gain control.
LC7.1E LB
SAW_SW
System
1
B/G, D/K, I
0
M/N
1
B/G, D/K, I
0
M/N
n.a.
M/N
DVB_SW
Mode
1
analogue reception
0
Digital reception
DC voltage (V)
RF AGC voltage
3.3 - 4.5 (weak or no signal)
< 3.3 (strong signal)
n.c.
2
I
C-bus address select
0
SCL
0 to 3.3
SDA
0 to 3.3
n.c.
5 ±0.25
supply voltage
n.c.
tuning supply voltage
33
n.c.
TV IF output
DC voltage (V)
n.c.
RF AGC voltage
3.3 - 4.5 (weak or no signal)
< 3.3 (strong signal)
2
I
C-bus address select
0
SCL
0 to 3.3
SDA
0 to 3.3
4 MHz reference output
5 ±0.25
supply voltage
broadband IF output
IF AGC voltage
0 to 3
narrowband IF output
narrowband IF output
9.
EN 75
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