ak4373 ETC-unknow, ak4373 Datasheet - Page 47

• Manufacturer Part Number: ak4373
• Description: Low Power Stereo Dac With Hp/spk-amp
• Manufacturer: ETC-unknow

(4) EQ
Note 41. [Translation the filter coefficient calculated by the equations above from real number to binary code (2’s
MS0991-E-00
fs: Sampling frequency
fc
fc
f: Input signal frequency
K: Filter gain [dB] (Maximum +12dB)
Register setting
X = (Real number of filter coefficient calculated by the equations above) x 2
X should be rounded to integer, and then should be translated to binary code (2’s complement).
MSB of each filter coefficient setting register is sign bit.
H(z) =
1
2
Transfer function
: Pole frequency
: Zero-point frequency
EQA[15:0] bits =A, EQB[13:0] bits =B, EQC[15:0] bits =C
(MSB=EQA15, EQB13, EQC15; LSB=EQA0, EQB0, EQC0)
A = 10
complement)]
A + Cz
1 + Bz
K/20
x
(Note
−1
−1
1 + 1 / tan (πfc
1 + 1 / tan (πfc
41)
M(f) =
2
1
/fs)
/fs)
A
1 + B
2
Amplitude
,
+ C
2
2
B =
+ 2ACcos (2πf/fs)
+ 2Bcos (2πf/fs)
1 − 1 / tan (πfc
1 + 1 / tan (πfc
- 47 -
1
1
/fs)
/fs)
θ(f) = tan
,
C =10
13
−1
A + BC + (AB+C)cos (2πf/fs)
K/20
x
(AB−C)sin (2πf/fs)
Phase
1 − 1 / tan (πfc
1 + 1 / tan (πfc
2
1
/fs)
/fs)
[AK4373]
2008/09