TDA7406 datasheet(21/64 Pages) STMICROELECTRONICS

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TDA7406

Description of the audioprocessor part

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Figure 8.

SoftStep-Timing for Volume

Note:

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

The Seven Band Equalizer

4.6.1

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.

1dB

0.5dB

-0.5dB

-1dB

SS Time

TDA7406 数据表(PDF) 21 Page - STMicroelectronics