TDA7406 Datasheet, PDF (21/64 Pages) STMicroelectronics – Car radio signal processor

TDA7406
Figure 8. SoftStep-Timing for Volume
Description of the audioprocessor part
1dB
0.5dB
Note:
-0.5dB
SS Time
-1dB
For steps more than 0.5dB (Volume) or 1dB (Speaker) the SoftStep mode should be
deactivated because it could generate a hard 1dB step during blending.
4.6
4.6.1
The Seven Band Equalizer
Equalizer Filter
Each filter is realized as a switched capacitor with a 2nd order frequency response.
There are three parameters programmable in the equalizer filter:
● Attenuation: ±15dB in 1db step resolution (Figure 9 shows the boost and cut response
as a function of frequency at a center frequency of 1kHz.)
● Center Frequency: This parameter is programmable in the filter stages 1(62/100Hz),
6(4/6.34kHz) and 7(15/16kHz). The others bands are fixed at: 157, 396, 1K and 2.5K
Hertz (see Figure 10).
● Quality Factors: The four possible quality factors are 1, 1.4, 1.8 and 2.2 (see
Figure 11).
The center frequency, Q, DC-mode and boost/cut can be set fully independently for each
filter. Figure 12 shows the superposition of all equalizer filter curves for different quality
factors.
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