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8
4994BS–AUDR–05/08
ATR4262M1 [Preliminary]
9. IF Filter Stage Concept
There are several different IF filter concepts possible depending on the broadcast standard and
the targeted quality range of the tuner. For that purpose a programmable switch for the FM mixer
output as well as three programmable inputs for the IF amplifier is available.
Figure 9-1. Example of Simple IF Filter Stage Concept
Table 9-1. IF Filter Stage Configuration
Configuration FMOUT AMFMOUT
Number of Mixer
Output Tanks
Number of IF
Filters
AM low cost
Not used or connected to
AMFMOUT
Mixer tank
Ceramic filter (BW 180 kHz)
11
AM ceramic filter
(compatible to DRM)
Mixer tank
Ceramic filter (BW 180 kHz)
Mixer tank
Ceramic filter (20 kHz)
22
AM crystal filter
Not used or connected to
AMFMOUT
Mixer tank
Ceramic filter (BW 180 kHz)
Crystal filter (BW 7 kHz)
12
AM crystal filter, separate
tank
Mixer tank
Ceramic filter (BW 180 kHz)
Mixer tank
Crystal filter (BW 7 kHz)
22
HD Radio
Mixer tank
Ceramic filter (BW 400 kHz)
Mixer tank
Ceramic filter (BW 180 kHz)
22
HD Radio low cost
Not used or connected to
AMFMOUT
Mixer tank
Ceramic filter (BW 400 kHz)
11
HD Radio with AM filter
Mixer tank
Ceramic filter (BW 400 kHz)
Mixer tank
Ceramic filter (BW 180 kHz)
Ceramic filter (BW 30 kHz)
23
IFREF
IFINAM
IFINFM
MXFMOUT
KF1
KF2
F2
C
CF2in
CIF2in CIF1in
RKF1out
1k8
RKF2out
330
+VS
Rin(IF2) Rin(IF1)
RS2
180
RS1
1k8
RF12
x
RF1out y
x + y = 300
Ω