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AK4141 Datasheet, PDF (23/96 Pages) Asahi Kasei Microsystems – NICAM/A2/EIA-J Digital Stereo Decoder | |||
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[AK4141]
â Digital Programmable Filter åè·¯
(1) ã¹ãã¬ãªæ強調ãã£ã«ã¿(FIL3)
åçãã¼ã¿ã 3D 強調ããããã®ãã£ã«ã¿ã§ããSDTO1/2ã®ãã£ã«ã¿ã®ä¿æ°ããããã F3A1[13-0],
F3A2[13-0], F3B1[13-0], F3B2[13-0] bits ã«ããè¨å®ãã¾ããã¾ããFIL3 ã¯F3AS 1/2 bit = â1â ã®ã¨ã High Pass
Filter (HPF)ãF3AS 1/2 bit = â0â ã®ã¨ã Low Pass Filter (LPF) ã¨ãªãã¾ããF3BP1/2 bit ã«ãã ON/OFF ãããã¨
ãå¯è½ã§ãã ã¹ãã¬ãªæ強調ãã£ã«ã¿ ãOFF ã®å ´åããªã¼ãã£ãªãã¼ã¿ã0dB ã§ã¹ã«ã¼ããã¾ãã ä¿æ°ã®
è¨å®ã¯ãF3BP1/2 bit = â1âã®ã¨ãè¡ã£ã¦ãã ããã
1) FIL3ãHPFã«è¨å®ããå ´å
fs: ãµã³ããªã³ã°å¨æ³¢æ°
fc: ã«ãããªãå¨æ³¢æ°
K: ã²ã¤ã³[dB] (0dB ï³ï Kï ï³ -10dB)
ã¬ã¸ã¹ã¿è¨å®(Figure 15)
FIL3: F3AS1, 2 bit = â1â, F3A1[13:0], F3A1[13:0] bits =A, F3B1[13:0], F3B2[13:0] bits =B
(MSB=F3A113(F3A213), F3B13(F3B213); LSB=F3A10(F3A20), F3B10(F3B20))
1 / tan (ï°fc/fs)
A = -10K/20x
,
1 + 1 / tan (ï°fc/fs)
1 ï 1 / tan (ï°fc/fs)
B=
1 + 1 / tan (ï°fc/fs)
ä¼éé¢æ°
1 ï z ï1
H(z) = A
1 + Bz ï1
2) FIL3ãLPFã«è¨å®ããå ´å
fs: ãµã³ããªã³ã°å¨æ³¢æ°
fc: ã«ãããªãå¨æ³¢æ°
K: ã²ã¤ã³[dB] (0dB ï³ï Kï ï³ -10dB)
ã¬ã¸ã¹ã¿è¨å®(Figure 15)
FIL3: F3AS1/2 bit = â0â, F3A1[13:0], F3A1[13:0] bits =A, F3B1[13:0], F3B2[13:0] bits =B
(MSB= F3A113(F3A213), F3B13(F3B213); LSB= F3A10(F3A20), F3B10(F3B20))
1
A = -10K/20x
,
1 + 1 / tan (ï°fc/fs)
1 ï 1 / tan (ï°fc/fs)
B=
1 + 1 / tan (ï°fc/fs)
ä¼éé¢æ°
1 + z ï1
H(z) = A
1 + Bz ï1
MS0952-J-03
- 23 -
2013/12
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