WM8753 Wolfson Microelectronics plc, WM8753 Datasheet - Page 37

• Manufacturer Part Number: WM8753
• Description: HI FI AND TELEPHONY DUAL CODEC
• Manufacturer: Wolfson Microelectronics plc

WM8753L
w
Table 25 Digital Volume Control
Table 26 Bass Filter Cut-off Frequencies for Different Frequencies
GRAPHIC EQUALISER
The WM8753L has a digital graphic equaliser and adaptive bass boost function. This function
operates on digital audio data before it is passed to the audio DACs. Bass enhancement can take two
different forms:
Treble control applies a user programmable gain, without any adaptive boost function. Bass and
treble control are completely independent with separately programmable gains and filter
characteristics.
The selectable cut-offs scale with sample frequency to give the following cut-off frequencies at
different sample rates
R8 (08h)
Left
Digital Volume
R9 (09h)
Right Channel
Digital Volume
REGISTER
ADDRESS
Channel
BC[2:0]
Linear bass control: bass signals are amplified or attenuated by a user
programmable gain. This is independent of signal volume, and very high bass gains
on loud signals may lead to signal clipping.
Adaptive bass boost: The bass volume is amplified by a variable gain. When the
bass volume is low, it is boosted more than when the bass volume is high. This
method is recommended because it prevents clipping, and usually sounds more
pleasant to the human ear.
000
001
010
011
100
101
8
7:0
8
7:0
BIT
CUT-OFF AT FS=8KHZ
LDACVOL
LDVU
[7:0]
RDVU
RDACVOL
[7:0]
LABEL
33.3Hz
66.7Hz
100Hz
200Hz
22Hz
50Hz
0
11111111
( 0dB )
0
11111111
( 0dB )
DEFAULT
CUT-OFF AT
FS=16KHZ
133.3Hz
66.7Hz
100Hz
200Hz
400Hz
44Hz
0 = Store LDACVOL in intermediate
latch (no gain change)
1 = Update left and right channel
gains (left = LDACVOL, right =
intermediate latch)
Left DAC Digital Volume Control
0000 0000 = Digital Mute
0000 0001 = -127dB
0000 0010 = -126.5dB
... 0.5dB steps up to
1111 1111 = 0dB
Left DAC Volume Update
0 = Store RDACVOL in intermediate
latch (no gain change)
1 = Update left and right channel
gains (left = intermediate latch, right
= RDACVOL)
Right DAC Digital Volume Control
similar to LDACVOL
Left DAC Volume Update
DESCRIPTION
AI Rev 3.1 June 2004
Advanced Information
CUT-OFF AT
FS=48KHZ
1200Hz
130Hz
200Hz
300Hz
400Hz
600Hz
37