WM8912
Production Data
RETUNETM MOBILE PARAMETRIC EQUALIZER (EQ)
The ReTuneTM Mobile Parametric Equaliser is a circuit that can be enabled in the DAC path. The
function of the EQ is to adjust the frequency characteristic of the output to compensate for unwanted
frequency characteristics in the loudspeaker (or other output transducer). It can also be used to tailor
the response according to user preferences, for example to accentuate or attenuate specific
frequency bands to emulate different sound profiles or environments such as concert hall, rock etc.
The EQ is enabled using the EQ_ENA bit as shown in Table 9.
REGISTER
ADDRESS
BIT
LABEL
EQ_ENA
DEFAULT
DESCRIPTION
R134 (86h)
EQ1
0
0
EQ enable
0 = EQ disabled
1 = EQ enabled
Table 9 ReTuneTM Mobile Parametric EQ Enable
The EQ can be configured to operate in two modes - “Default” mode or “ReTuneTM Mobile” mode.
DEFAULT MODE (5-BAND PARAMETRIC EQ)
In default mode, the cut-off / centre frequencies are fixed as per Table 10. The filter bandwidths are
also fixed in default mode. The gain of the individual bands (-12dB to +12dB) can be controlled as
described in Table 11.
Note that the cut-off / centre frequencies noted in Table 10 are applicable to a DAC Sample Rate of
48kHz. When using other sample rates, these frequencies will be scaled in proportion to the selected
sample rate.
EQ BAND
CUT-OFF/CENTRE
FREQUENCY
1
2
3
4
5
100 Hz
300 Hz
875 Hz
2400 Hz
6900 Hz
Table 10 EQ Band Cut-off / Centre Frequencies
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
EQ Band 1 Gain
R135 (87h)
EQ2
4:0
EQ_B1_GAIN [4:0]
01100b
(0dB)
(see Table 12 for gain range)
EQ Band 2 Gain
R136 (88h)
EQ3
4:0
4:0
4:0
4:0
EQ_B2_GAIN [4:0]
EQ_B3_GAIN [4:0]
EQ_B4_GAIN [4:0]
EQ_B5_GAIN [4:0]
01100b
(0dB)
(see Table 12 for gain range)
EQ Band 3 Gain
R137 (89h)
EQ4
01100b
(0dB)
(see Table 12 for gain range)
EQ Band 4 Gain
R138 (8Ah)
EQ5
01100b
(0dB)
(see Table 12 for gain range)
EQ Band 5 Gain
R139 (8Bh)
EQ6
01100b
(0dB)
(see Table 12 for gain range)
Table 11 EQ Band Gain Control
PD, Rev 4.0, September 2010
28
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
