TDA7460N
Figure 2. Input stages
15K
CD
-
+
15K
CDGND
15K
PHONE
-
+
15K
PH_GND
CASSETTE
100K
15K
IN GAIN
15K
15K
15K
100K
AM
100K
STEREODECODER
100K
D97AU633A
MPX
Mixing Stage
This stage offers the possibility to mix the internal
beep or the phone signal to any other source.
Due to the fact that the mixing stage is also lo-
cated behind the In-Gain stage fine adjustments
of the main source level can be done in this way.
Loudness
There are four parameters programmable in the
loudness stage (see fig. 3, 4, 5):
-
-
-
-
Attenuation
Center Frequency
Loudness Q
Flat Mode: in this mode the loudness stage works
as a 0 - 15dB attenuator.
Figure 3. Loudness Attenuation @ fc = 400Hz
(second order)
0.0
-5.0
-10.0
-15.0
-20.0
10.0
100.0
1.0K
10.0K
Figure 4. Loudness Center frequency @ Attn.
= 15dB (second order)
0.0
Softmute
The digitally controlled softmute stage allows
muting/demuting the signal with a I
2
C bus pro-
grammable slope. The mute process can either
be activated by the softmute pin or by the I
2
C
bus. The slope is realized in a special S shaped
curve to mute slow in the critical regions (see fig-
ure 6).
For timing purposes the Bit 3 of the I
2
C bus out-
put register is set to 1 from the start of muting un-
til the end of demuting.
-5.0
-10.0
-15.0
-20.0
10.0
100.0
1.0K
10.0K
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