STA013 datasheet(27/38 Pages) STMICROELECTRONICS

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TONE_ATTEN

Address: 0x7D

Type: RW

Software Reset: 0x00

Hardware Reset: 0x00

MSB

LSB

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

-1.5dB step

000

0dB

000

-1.5dB

000

-3dB

000

-4.5dB

001010

-15dB

001011

-16.5dB

001100

-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)

44.1

22.5

11.025

MPEG Frame Lenght (ms)

STA013 - STA013B - STA013T

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