TDA7405_04 Datasheet, PDF (13/57 Pages) STMicroelectronics – EQUALIZER CARRADIO SIGNAL PROCESSOR

5.4.3 Loudness Order
Different shapes of 1st and 2nd-Order Loudness
Figure 8. 1st and 2nd Order Loudness @ Attn. = 15dB, fP=400Hz
0.0
TDA7405
-5.0
dB
-10.0
-15.0
-20.0
10.0
100.0
Hz
1.0K
10.0K
5.4.4 Flat Mode
In flat mode the loudness stage works as a 0dB to -19dB attenuator.
5.5 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 spe-
cial S-shaped curve to mute slow in the critical regions (see Figure 9). For timing purposes the Bit of the I2C-
bus output register is set to 1 from the start of muting until the end of de-muting.
Figure 9. Softmute-Timing
Note: 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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