AK4646EN AKM [Asahi Kasei Microsystems], AK4646EN Datasheet - Page 35

• Manufacturer Part Number: AK4646EN
• Description: Stereo CODEC with MIC/SPK-AMP
• Manufacturer: AKM [Asahi Kasei Microsystems]

(3) Stereo Separation Emphasis Filter (FIL3)
FIL3 is used to emphasize the stereo separation of stereo mic recording data or playback data. F3A13-0 and F3B13-0 bits
set the filter coefficient of FIL3. FIL3 becomes High Pass Filter (HPF) at F3AS bit = “0”, and Low Pass Filter (LPF) at
F3AS bit = “1”. FIL3 bit controls ON/OFF of FIL3. When Stereo Separation Emphasis Filter is OFF, the audio data
passes this block by 0dB gain. The coefficient should be set when FIL3 bit = “0” or PMADL = PMADR = PMDAC bits
= “0”.
1) When FIL3 is set to “HPF”
Register setting (Note 34)
2) When FIL3 is set to “LPF”
Register setting (Note 34)
MS0557-E-02
fs: Sampling frequency
fc: Cut-off frequency
K: Filter gain [dB] (0dB ≥ K ≥ − 10dB)
fs: Sampling frequency
fc: Cut-off frequency
K: Filter gain [dB] (0dB ≥ K ≥ − 10dB)
FIL3: F3AS bit = “0”, F3A[13:0] bits =A, F3B[13:0] bits =B
(MSB=F3A13, F3B13; LSB=F3A0, F3B0)
Transfer function
FIL3: F3AS bit = “1”, F3A [13:0] bits =A, F3B [13:0] bits =B
(MSB=F3A13, F3B13; LSB= F3A0, F3B0)
Transfer function
A = 10
H(z) = A
A = 10
H(z) = A
K/20
K/20
x
x
1 + Bz
1 + Bz
1 − z
1 + z
1 + 1 / tan (πfc/fs)
1 + 1 / tan (πfc/fs)
1 / tan (πfc/fs)
−1
−1
−1
−1
1
,
,
B =
B =
1 − 1 / tan (πfc/fs)
1 + 1 / tan (πfc/fs)
1 − 1 / tan (πfc/fs)
1 + 1 / tan (πfc/fs)
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[AK4646]
2007/05