wm9081 Wolfson Microelectronics plc, wm9081 Datasheet - Page 34

• 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

WM9081
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The slope of the DRC response is determined by register fields DRC_HI_COMP and
DRC_LO_COMP. A slope of 1 indicates constant gain in this region. A slope less than 1 represents
compression (i.e. a change in input amplitude produces only a smaller change in output amplitude).
A slope of 0 indicates that the target output amplitude is the same across a range of input
amplitudes; this is infinite compression.
The DRC Compression parameters are listed in Table 11.
Table 11 DRC Compression Parameters
The knee Figure 25 is defined by register fields DRC_KNEE_IP and DRC_KNEE_OP respectively.
Parameter Y0, the output level for a 0dB input, is not specified directly, but can be calculated from
the other parameters, using the equation:
The registers which control the DRC Compression parameters are shown in Table 12.
R34 (22h)
DRC 3
R35 (23h)
DRC 4
DRC_KNEE_IP
DRC_KNEE_OP
DRC_HI_COMP
DRC_LO_COMP
REGISTER
ADDRESS
PARAMETER
10:5
BIT
5:3
2:0
Input level at the knee (dB)
Output level at the knee (dB)
Compression ratio above knee
Compression ratio below knee
DRC_HI_COMP
[2:0]
DRC_LO_COMP
[2:0]
DRC_KNEE_IP
[5:0]
LABEL
DESCRIPTION
DEFAULT
00_0000
000
000
Compressor slope (upper region)
000 = 1 (no compression)
001 = 1/2
010 = 1/4
011 = 1/8
100 = 1/16
101 = 0
110 = Reserved
111 = Reserved
Compressor slope (lower region)
000 = 1 (no compression)
001 = 1/2
010 = 1/4
011 = 1/8
100 = 0
101 = Reserved
11X = Reserved
Input signal level at the Compressor
‘knee’.
000000 = 0dB
000001 = -0.75dB
000010 = -1.5dB
… (-0.75dB steps)
111100 = -45dB
DESCRIPTION
PP, Rev 3.0, April 2009
Pre-Production
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