TDA7404D

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1.6 SoftStep-Volume

When the volume-level is changed audible clicks could appear at the output. The root cause of those clicks

could either be a DC-Offset before the volume-stage or the sudden change of the envelope of the audiosignal.

With the SoftStep-feature both kinds of clicks could be reduced to a minimum and are no more audible. Four

programmable soft step time from one step to the next, are user selectable.

Figure 7. SoftStep-Timing

Note: For steps more than 1dB the SoftStep mode should be deactivated because it could generate a 1dB error during the blend-time.

1.7 Bass

There are three parameters programmable in the bass stage:

1.7.1 Attenuation

Figure 8 shows the attenuation as a function of frequency at a center frequency of 80Hz.

Figure 8. Bass Control @ fC = 80Hz, Q = 1

Time

SS Time

-1dB

-2dB

Vout

2dB

1dB

-15.0

-10.0

-5.0

0.0

5.0

10.0

15.0

10.0

100.0

1.0K

10.0K

dB

Hz