MSP3415G ETC, MSP3415G Datasheet - Page 12

• Manufacturer Part Number: MSP3415G
• Description: MSP 34x5G Multistandard Sound Processor Family
• Manufacturer: ETC

MSP 34x5G
2.3. Preprocessing for SCART and
The SCART and I
level by means of the SCART and I
ters.
2.4. Source Selection and Output Channel Matrix
The Source Selector makes it possible to distribute all
source signals (one of the demodulator source chan-
nels or SCART) to the desired output channels (loud-
speaker, etc.). All input and output signals can be pro-
cessed simultaneously. Each source channel is
identified by a unique source address.
For each output channel, the sound mode can be set
to sound A, sound B, stereo, or mono by means of the
output channel matrix.
If Automatic Sound Select is on, the output channel
matrix can stay fixed to stereo (transparent) for demod-
ulated signals.
12
I
2
S Input Signals
2
S inputs need only be adjusted in
2
S prescale regis-
2.5. Audio Baseband Processing
2.5.1. Automatic Volume Correction (AVC)
Different sound sources (e.g. terrestrial channels, SAT
channels, or SCART) fairly often do not have the same
volume level. Advertisements during movies usually
have a higher volume level than the movie itself. This
results in annoying volume changes. The AVC solves
this problem by equalizing the volume level.
To prevent clipping, the AVC’s gain decreases quickly
in dynamic boost conditions. To suppress oscillation
effects, the gain increases rather slowly for low level
inputs. The decay time is programmable by means of
the AVC register (see page 30).
For input signals ranging from 24 dBr to 0 dBr, the
AVC maintains a fixed output level of 18 dBr. Fig. 2–4
shows the AVC output level versus its input level. For
prescale and volume registers set to 0 dB, a level of
0 dBr corresponds to full scale input/output. This is
– SCART input/output 0 dBr = 2.0 V
– Loudspeaker output 0 dBr = 1.4 V
Fig. 2–4: Simplified AVC characteristics
2.5.2. Loudspeaker Outputs
The following baseband features are implemented in
the loudspeaker output channels: bass/treble, loud-
ness, balance, and volume. A square wave beeper can
be added to the loudspeaker channel.
2.5.3. Quasi-Peak Detector
The quasi-peak readout register can be used to read
out the quasi-peak level of any input source. The fea-
ture is based on following filter time constants:
attack time: 1.3 ms
decay time: 37 ms
output level
[dBr]
18
24
30
24
18
12
PRELIMINARY DATA SHEET
6
0
rms
rms
input level
Micronas
[dBr]