TDA7418 Datasheet, PDF (14/29 Pages) STMicroelectronics – 3 Band car audio procesor

Description of the audioprocessor
TDA7418
4.3.3
Low & High frequency boost
Figure 6 shows the different Loudness shapes in low & high frequency boost.
Figure 6. Loudness Attenuation, fc = 2.4kHz
4.3.4
4.4
Flat mode
In flat mode the loudness stage works as a 0dB to -15dB attenuator.
SoftMute
The digitally controlled SoftMute stage allows muting/demuting the signal with a I²C-bus
programmable slope. The mute process can either be activated by the SoftMute pin or by
the I²C-bus. This slope is realized in a special S-shaped curve to mute slow in the critical
regions (see Figure 7).
For timing purposes the Bit0 of the I²C-bus output register is set to 1 from the start of muting
until the end of demuting.
Figure 7. Softmute-Timing
1
EXT.
MUTE
+SIGNAL
REF
-SIGNAL
1
I²C BUS
OUT
D97AU634
Time
1. Please notice that a started Mute-action is always terminated and could not be interrupted by a change of
the mute-signal
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