WM8983GEFL/RV Wolfson Microelectronics, WM8983GEFL/RV Datasheet - Page 41

• Manufacturer Part Number: WM8983GEFL/RV
• Description: Audio CODECs Mbl Multimedia CODEC w/ 1W Speaker Driver
• Manufacturer: Wolfson Microelectronics

Specifications of WM8983GEFL/RV

• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-32
• Minimum Operating Temperature: - 25 C

Production Data
w
PROGRAMMABLE IIR NOTCH FILTER
Table 17 Notch Filter Function
A programmable notch filter is provided. This filter has a variable centre frequency and bandwidth,
programmable via two coefficients, a0 and a1. 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.
Where:
f
The actual register values can be determined from the coefficients as follows:
The coefficients are calculated as follows:
a
w
w
c
R27
Notch Filter 1
R28
Notch Filter 2
R29
Notch Filter 3
R30
Notch Filter 4
1
= centre frequency in Hz, f
0
b
REGISTER
ADDRESS
=
=
=
−
2
2
π
π
1 (
NFA0 = -a0 x 2
NFA1 = -a1 x 2
a
f
f
c
0
b
+
/
/
=
a
f
f
s
0
1
1
s
)
−
+
cos(
6:0
7
8
6:0
8
6:0
8
0-6
8
tan(
tan(
BIT
13
12
w
w
w
0
b
b
b
)
= -3dB bandwidth in Hz, f
NFA0[13:7]
NFEN
NFU
NFA0[6:0]
NFU
NFA1[13:7]
NFU
NFA1[6:0]
NFU
/
/
) 2
) 2
LABEL
DEFAULT
0
0
0
0
0
0
0
0
0
s
= sample frequency in Hz
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.
DESCRIPTION
PD Rev 4.0 November 2006
WM8983
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