wm9081 Wolfson Microelectronics plc, wm9081 Datasheet - Page 35

• Manufacturer Part Number: wm9081
• Description: Mono Dac With 2.6w Class Ab/d Speaker Driver, Dynamic Range Controller And Retune Mobile Parametric Equalizer
• Manufacturer: Wolfson Microelectronics plc

Pre-Production
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Table 12 DRC Compression Control
GAIN LIMITS
The minimum and maximum gain applied by the DRC is set by register fields DRC_MINGAIN and
DRC_MAXGAIN. These limits can be used to alter the DRC response from that illustrated in Table
13. If the range between maximum and minimum gain is reduced, then the extent of the dynamic
range control is reduced. The maximum gain prevents quiet signals (or silence) from being
excessively amplified.
Table 13 DRC Gain Limits
DYNAMIC CHARACTERISTICS
The dynamic behaviour determines how quickly the DRC responds to changing signal levels. Note
that the DRC responds to the average (RMS) signal amplitude over a period of time.
The DRC_ATK register determines how quickly the DRC gain decreases when the signal amplitude
is high. The DRC_DCY register determines how quickly the DRC gain increases when the signal
amplitude is low.
These register fields are described in Table 14. Note that the register defaults are suitable for general
purpose use.
R33 (21h)
DRC 2
REGISTER
ADDRESS
REGISTER
ADDRESS
BIT
3:2
1:0
BIT
4:0
DRC_MINGAIN[1:0]
DRC_MAXGAIN[1:0]
[4:0]
DRC_KNEE_OP
LABEL
LABEL
DEFAULT
0_0000
DEFAULT
00
00
111101 = Reserved
11111X = Reserved
Output signal at the Compressor
‘knee’.
00000 = 0dB
00001 = -0.75dB
00010 = -1.5dB
… (-0.75dB steps)
11110 = -22.5dB
11111 = Reserved
Minimum gain the DRC can use
to attenuate audio signals
00 = 0dB (default)
01 = -6dB
10 = -12dB
11 = -18dB
Maximum gain the DRC can use
to boost audio signals
00 = 12dB
01 = 18dB (default)
10 = 24dB
11 = 36dB
DESCRIPTION
DESCRIPTION
PP, Rev 3.0, April 2009
WM9081
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