TDA7416 Datasheet, PDF (16/27 Pages) STMicroelectronics – CARRADIO SIGNAL PROCESSOR

TDA7416
1.9 AC-coupling
In some applications additional signal manipulations are desired. For this purpose an AC-coupling is
placed before the speaker(fader)-attenuators, which can be activated or internally shorted by I²C-Bus. In
short condition the input-signal of the speaker-attenuator is available at the AC-outputs. The input-imped-
ance of this AC-inputs is 50k . In addition there are Mix inputs available. With this inputs it is possible to
mix an external signal to every speaker with a mixing ratio of 50% (see figure 14).
The source of front and rear speaker can be set independently.
As source is choosable : - internal dc coupling (not recommended)
- external ac coupling using ACin pins
Figure 15. AC/DC-coupling
ACoutL SWout
SWin
ACinL
left channel
Highpass
fr
flat
Vref
Vref
Front Fader
Re a rFader
right channel
Rear selector
Lowpass
fr
flat
Subwoofer Fader
1.10 Front Speaker-Attenuator and Mixing
A Mixing-stage is placed after front speaker-attenuator and can be set independently to mixing-mode.
Having a full volume for the Mix-signal the stage offers a wide flexibility to adapt the mixing levels.
Figure 16. Output Selector
Front
Volume
+15/-79dB
1dB step
Highpass2
1
OutF
From M I Xin
Volume
+15/-79dB
1dB step
1.11 Audioprocessor Testing
During the Testmode, which can be activated by setting bit I₂ of the subaddress byte and D₀ of the audio-
processor testing byte, several internal signals are available at the Mix pin. During this mode the input
resistance of 100kOhm is disconnected from the pin. The internal signals available are shown in the Data-
byte specification.
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