TDA7407 Datasheet, PDF (13/30 Pages) STMicroelectronics – ADVANCED CAR SIGNAL PROCESSOR

TDA7407
Figure 5. Softmute Timing
1
EXT.
MUTE
+SIGNAL
REF
-SIGNAL
1
I²C BUS
OUT
D97AU634
Time
Note: Please notice that a started Mute action is always terminated
and could not be interrupted by a change of the mute signal.
ure 5).
For timing purposes the Bit 3 of the I²C bus out-
put register is set to 1 from the start of muting un-
til the end of demuting.
BASS
There are four parameters programmable in the
bass stage: (see figs 6, 7, 8, 9):
Attenuation
Figure 6 shows the attenuation as a function of
frequency at a center frequency at a center fre-
quency of 80Hz.
Center Frequency
Figure 7 shows the four possible center frequen-
cies 60,70,80 and 100Hz.
Quality Factors
Figure 8 shows the four possible quality factors 1,
1.25, 1.5 and 2.
DC Mode
In this mode the DC gain is increased by 5.1dB. In ad-
dition the programmed center frequency and quality
factor is decreased by 25% which can be used to
reach alternative center frequencies or quality factors.
MID
There are 3 parameters programmable in the mid
stage (see figs. 10, 11 & 12)
Attenuation
Figure 10 shows the attenuation as a function of
frequency at a center frequency of 1kHz.
Center Frequency
Figure 11 shows the four possible center frequen-
cies 500Hz, 1kHz, 1.5kHz and 2kHz.
Quality Factor
Figure 12 shows the two possible quality factors
1 and 2 at a center frequency of 1kHz.
TREBLE
There are two parameters programmable in the
treble stage (see figs 13, 14):
Attenuation
Figure 13 shows the attenuation as a function of
frequency at a center frequency of 17.5KHz.
Center Frequency
Figure 14 shows the four possible Center Fre-
quency (10, 12.5, 15 and 17.5kHz).
AC Coupling
In some applications additional signal manipula-
tions are desired, for example surround-sound or
more-band-equalizing.
For this purpose a AC-Coupling is placed before
the Speaker-attenuators, which can be activated
or internally shorted by Bit7 in the Bass/Treble-
Configuration byte. In short condition the input-
signal of the speaker-attenuator is available at
AC Outputs and the AC Input could be used as
additional stereo inputs. The input impedance of
the AC Inputs is always 50KΩ.
Speaker Attenuator
The speaker attenuators have exactely the same
Figure 6. Bass Control @ fc = 80Hz, Q = 1
15.0
10.0
5.0
0.0
-5.0
-10.0
-15.0
10.0
100.0
1.0K
10.0K
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