Audio CODECs VoIP Mono CODEC

WM8510GEDS/V

Manufacturer Part NumberWM8510GEDS/V
DescriptionAudio CODECs VoIP Mono CODEC
ManufacturerWolfson Microelectronics
WM8510GEDS/V datasheet
 


Specifications of WM8510GEDS/V

Operating Supply Voltage- 0.3 V to + 7 VMaximum Operating Temperature+ 85 C
Mounting StyleSMD/SMTPackage / CaseSSOP-28
Minimum Operating Temperature- 25 CLead Free Status / RoHS StatusLead free / RoHS Compliant
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Production Data
PROGRAMMABLE NOTCH FILTER
A programmable notch filter is provided. This filter has a variable centre frequency and bandwidth,
programmable via two coefficients, a0 and a1. These coefficients should be converted to 2’s
complement numbers to determine the register values. a0 and a1 are represented by the register bits
NFA0[13:0] and NFA1[13:0]. Because these coefficient values require four register writes to setup
there is an NFU (Notch Filter Update) flag which should be set only when all four registers are setup.
REGISTER
ADDRESS
R27
Notch Filter 1
R28
Notch Filter 2
R29
Notch Filter 3
R30
Notch Filter 4
Table 12 Notch Filter Function
The coefficients are calculated as follows:
Where:
The coefficients are calculated as follows:
NFA0 = -a0 x 2
NFA1 = -a1 x 2
These values are then converted to 2’s complement notation to determine the register values.
NOTCH FILTER WORKED EXAMPLE
The following example illustrates how to calculate the a0 and a1 coefficients for a desired centre
frequency and -3dB bandwidth.
fc = 1000 Hz
w
BIT
LABEL
DEFAULT
6:0
NFA0[13:7]
0
7
NFEN
0
8
NFU
0
6:0
NFA0[6:0]
0
8
NFU]
0
6:0
NFA1[13:7]
0
8
NFU
0
6:0
NFA1[6:0]
0
8
NFU
0
1
tan(
w
/
) 2
=
b
a
0
+
1
tan(
w
/
) 2
b
=
+
a
1 (
a
)
cos(
w
)
1
0
0
π
=
w
2
f
/
f
0
c
s
π
=
w
2
f
/
f
b
b
s
f
= centre frequency in Hz, f
= -3dB bandwidth in Hz, f
c
b
13
12
WM8510
DESCRIPTION
Notch Filter a0 coefficient, bits [13:7]
Notch filter enable:
0=Disabled
1=Enabled
Notch filter update. The notch filter
values used internally only update when
one of the NFU bits is set high.
Notch Filter a0 coefficient, bits [6:0]
Notch filter update. The notch filter
values used internally only update when
one of the NFU bits is set high.
Notch Filter a1 coefficient, bits [13:7]
Notch filter update. The notch filter
values used internally only update when
one of the NFU bits is set high.
Notch Filter a1 coefficient, bits [6:0]
Notch filter update. The notch filter
values used internally only update when
one of the NFU bits is set high.
= sample frequency in Hz
s
PD, Rev 4.5, September 2008
21