TDA7406 Datasheet, PDF (25/64 Pages) STMicroelectronics – Car radio signal processor

TDA7406
Description of the audioprocessor part
Figure 15. Spectrum analyzer block diagram
Figure 16. Timing spectrum analyzer
4.9
AC-coupling
In some applications additional signal manipulations are desired. For this purpose an AC-
coupling is placed before the speaker-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-impedance of this AC-inputs is 50kΩ. In addition there are Mix_In
inputs available. With this inputs it is possible to mix an external signal to every speaker with
a mixing ratio of 50% (see Figure 17).
The source of front and rear speaker can be set independently. As source is possible to
choose:
– internal dc coupling (not recommended)
– external ac coupling using AC_In pins
– external ac coupling using Mix_In pins
– mixing of AC_In and Mix_In pins (mixing ratio: 50%)
If the Mix_In pins of the rear speaker are not used this inputs can be used as mixing inputs for
the internal subwoofer filter.
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