Datasheet

TONE_ATTEN
Address: 0x7D
Type: RW
Software Reset: 0x00
Hardware Reset: 0x00
MSB LSB
b7 b6 b5 b4 b3 b2 b1 b0
TA7 TA6 TA5 TA4 TA3 TA2 TA1 TA0
In the digital output audio, the full signal is
achieved with 0 dB of attenuation. For this rea-
son, before applying Bass & Treble Control, the
user has to set the TONE_ATTEN register to the
maximum value of enhancement is going to per-
form.
For example, in case of a 0 dB signal (max. level)
only attenuation would be possible. If enhance-
ment is desired, the signal has to be attenuated
accordingly before in order to reserve a margin in dB.
An increment of a decimal unit corresponds to a Tone
Attenuation step of 1.5dB.
MSB LSB ATTENUATION
b7 b6 b5 b4 b3 b2 b1 b0 -1.5dB step
00000000 0dB
00000001 -1.5dB
00001010 -3dB
00000011 -4.5dB
.
.
.
00001010 -15dB
00001011 -16.5dB
00001100 -18dB
DEMULTIPLEXING
&
ERROR CHECK
HUFFMAN
DECODING
D98AU903
INVERSE
QUANTISATION
&
DESCALING
SIDE INFORMATION
DECODING
INVERSE
FILTERBANK
IMDCT
STEREOPHONIC AUDIO
SIGNAL (2*768Kbit/s)
ENCODED AUDIO
BITSTREAM (8Kbit/s ... 128Kbit/s)
ANCILLARY DATA
5.1. MPEG 2.5 Layer III Algorithm.
5.2 - MPEG Ancillary Data Description:
As specifyed in the ISO standard, the MPEG
Layer III frames have a variable bit lenght, and
are constant in time depending on the audio sam-
pling frequencies. The time duration of the Layer
III frames is shown in Tab 2.
5. GENERAL INFORMATION
Table2:
MPEG Layer III Frames Time Duration
Sampling Frequency (KHz) 48 44.1 32 24 22.5 16 12 11.025 8
MPEG Frame Lenght (ms) 24 29 36 24 29 36 48 48 72
STA013 - STA013B - STA013T
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