STV8247 datasheet(37/156 Pages) STMICROELECTRONICS

37 / 156 page

37/156

STV82x7

Dedicated Digital Signal Processor (DSP)

The SVC is implemented on the loudspeakers path, headphone path or on both in parallel

(independent settings). Also, the SVC can be applied in six-channel mode (L, R, LS, RS, C and

SubW).

4.9

ST Dynamic Bass

STV82x7 offers dynamic bass boost processing on the Loudspeakers path:

ST Dynamic Bass is a bass boost process that can dramatically increase the bass content of any

program without any output level saturation.

3 cutoff frequencies (BASS_FREQ) can be chosen, 100 Hz, 150 Hz and 200 Hz to adapt the effect

to your loudspeakers. The amount of bass (BASS_LEVEL) can also be fine tuned in order to adapt

the effect loudness.

4.10

5-Band Audio Equalizer

The loudspeakers audio spectrum is split into 5 frequency bands and the gain of each of band can

be adjusted within a range from -12 dB to +12 dB in steps of 0.25 dB. The Audio Equalizer may be

used to pre-define frequency band enhancement features dedicated to various kinds of music or to

attenuate frequency resonances of loudspeakers or the listening environment. The Equalizer is

enabled by the LS_EQ_ON bit in the LS_EQ_BT_CTRL register. The gain value for Band X is

programmed in register EQ_BANDX_GAIN.

The 5-Band Audio Equalizer is exclusive with Bass-Treble control. Bit LS_EQ_BT_SW in register

LS_EQ_BT_CTRL is used to select either the 5-Band Audio Equalizer or the Bass-Treble control for

the Loudspeakers path.

Depending on the LS Equalizer or LS Bass-Treble value, the volume level can be clamped to the LS

output to prevent any possible signal clipping from occuring using the ANTICLIP_LS_VOL_CLAMP

bit in the VOLUME_MODES (D7h) register.

4.11

Bass/Treble Control

The gain of bass and treble frequency bands for Headphone can be also tuned within a range from

-12 dB to +12 dB in steps of 0.25 dB. It may be used to pre-define frequency band enhancement

features dedicated to various kinds of music. The Headphone Bass/Treble feature is enabled by

setting the HP_BT_ON bit in the HP_BT_CONTROL register. The Bass and Treble gain values are

adjusted in registers HP_BASS_GAIN and HP_TREBLE_GAIN, respectively.

Depending on the HP Bass-Treble value, the volume level can be clamped to the HP output to

prevent any possible signal clipping from occuring using the ANTICLIP_HP_VOL_CLAMP bit in the

VOLUME_MODES (D7h) register.

Figure 19: Equalizer

f1 = 100 Hz, f2 = 330 Hz, f3 = 1 kHz, f4 = 3.3 kHz and f5 = 10 kHz

STV8247 bảng dữ liệu(PDF) 37 Page - STMicroelectronics