ACS422A68TAGZBX8 IDT, ACS422A68TAGZBX8 Datasheet - Page 26

• Manufacturer Part Number: ACS422A68TAGZBX8
• Description: Interface - CODECs
• Manufacturer: IDT

Specifications of ACS422A68TAGZBX8

• Rohs: yes
• Part # Aliases: IDTACS422A68TAGZBX8

ACS422x68
LOW-POWER, HIGH-FIDELITY, INTEGRATED CODEC
©2011 INTEGRATED DEVICE TECHNOLOGY, INC.
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General compressor/limiter/expander control
Compressor/Limiter/Expander make-up gain
R37 (25h)
CLECTL
R38 (26h)
MUGAIN
Register Address
Register Address
3.7.4.
3. Attack/Release filter: In order to prevent objectionable artifacts, the gain is smoothly ramped
This creates a exponential ramp from the current gain value to the new value.
Limiter/Compressor Registers
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from the current value to the new value calculated by the gain calculation block. In the PC-based
comp/limiter, this is achieved using a simple tracking lowpass filter to smooth out the abrupt tran-
sitions. The calculation (using the coefficient (coeff) selected by the gain block) is:
Filtered_gain = coeff*last_filtered_gain + (1.0 - coeff)*target_gain;
In the compression region:
In the linear region:
Bit
7:5
Bit
7:5
4:0
4
3
2
1
0
If the gain calculated is less than the last gain calculated (more compression is being
applied), then the filter coefficient is the compressor attack.
If the gain calculated is more than the last gain calculated (less compression), the filter coef-
ficient is the compressor release.
In the expansion region:
If the calculated gain is less than the last gain calculated (closing expander, the filter coeffi-
cient is the expander attack.
If the calculated gain is more than the last gain calculated, the filter coefficient is the
expander release.
Modify gain until a gain of 1.0 is obtained.
If the last non-linear state was compression, use the compressor release.
If the last non-linear state was expansion, use the expander attack.
CLEMUG[4:0]
WindowSel
Lvl_Mode
Comp_en
Limit_en
Exp_en
RSVD
RSVD
Label
Label
Table 15. CLECTL Register
Table 16. MUGAIN Register
Type
Type
RW
RW
RW
RW
RW
RW
R
R
Default
Default
26
0h
0h
0h
0
0
0
0
0
Reserved
CLE Level Detection Mode
0 = Average
1 = Peak
Window width selection for level detection:
0 = equivalent of 512 samples of selected Base Rate
(~10-16ms)
1 = equivalent of 64 samples of selected Base Rate
(~1.3-2ms)
1 = enable expander
1 = enable limiter
1 = enable compressor
Reserved
0dB..46.5dB in 1.5dB steps
Description
Description
ACS422X68
V1.6 01/13