STV8206 Datasheet, PDF (20/97 Pages) STMicroelectronics – Multistandard TV Audio Processor and Digital Sound Demodulator

Audio Processor Block
STV82x6
features dedicated to various kinds of music, to implement programmable Loudness or Super-bass
functions. The Headphone Bass/Treble feature is enabled by setting the BT_ON bit in the
HP_BT_CTRL register. The Bass and Treble gain values are adjusted in registers HP_BASS_GAIN
and HP_TREBLE_GAIN, respectively.
3.6 Volume/Balance Control
The STV82x6 provides a Volume/Balance Control for each of the Loudspeaker, Subwoofer and
Headphone audio outputs. Its wide range (from 0 to -96 dB in a linear scale) largely covers typical
home applications (approx. 60 dB) while maintaining a good S/N ratio. Its fine resolution (0.375 dB)
provides simple volume programming and a relative OSD scale representation. The Loudspeaker,
Subwoofer and Headphone volume values should be programmed progressively in steps of less
than 1 dB in order to prevent audible envelope variations and a minimum duration of 16 ms is
required between two successive programming commands to guarantee that there are no audible
plops during volume changes. In this case, a full 8-bit volume scan with minimum steps of 0.375 dB
will last approximately 4 s (minimum).
Figure 11: Volume Control
0 dB
-96 dB
Mute
00h
I²C Control
FFh
The Volume/Balance Control can operate in one of two different modes:
● In Differential mode (default value), the volume control is a common volume value for both the
Left and Right Loudspeaker and Headphone channels.
● In Independent mode, the volume for the Left and Right channels for Loudspeakers or
Headphone is controlled independently.
As the Loudspeaker bass frequencies are output by the Subwoofer, its reference volume is
controlled by default with the value of the LS_CVOL common volume register. The SW_GAIN
register value is used to adjust the level of the Subwoofer output in regards to this reference. In
Independent mode, the SW_GAIN register is used as a separated volume control and does not take
into account the Loudspeaker audio level.
3.6.1
Differential Mode
The common value for the Right/Left volume controls for the Loudspeaker, Subwoofer and
Headphone outputs are programmed in registers LS_CVOL, SW_GAIN and HP_CVOL,
respectively. A differential balance can be applied using registers LS_BAL and HP_BAL to adjust
the Left/Right level ratio as shown in Figure 12.
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