AK4647VQ Datasheet, PDF (34/72 Pages) Asahi Kasei Microsystems – Stereo CODEC with MIC/HP-AMP

ASAHI KASEI
[AK4647]
2. ALCϦΧόϦಈ࡞
ALCϦΧόϦಈ࡞͸ɺWTM1-0 bitsͰઃఆ͞Εͨ࣌ؒ(Table 26)଴ػΛߦ͍ɺ͜ͷؒɺग़ྗ৴߸͕ALCϦΧό
Ϧ଴ػΧ΢ϯλϦηοτϨϕϧ(Table 23)Λӽ͢͜ͱ͕ͳ͚Ε͹ALCϦΧόϦಈ࡞Λߦ͍·͢ɻ͜ͷALCϦΧ
όϦಈ࡞͸ઃఆ͞Εͨج४Ϩϕϧ(Table 28) ·ͰZTM1-0 bitsͰઃఆͨ࣌ؒ͠(Table 25)ͰθϩΫϩεݕग़ಈ࡞
Λߦ͍ͳ͕ΒɺRGAIN1-0 bitsͰઃఆͨ͠஋(Table 27)͚ͩIVL, IVR஋(L/Rڞ௨)Λࣗಈతʹ૿Ճͤ͞·͢ɻ͜
ͷALCϦΧόϦಈ࡞͸WTM1-0 bitsͰઃఆͨ͠पߦͰظΘΕ·͢ɻ
ྫ͑͹ɺࡏݱͷIVL, IVR஋͕30Hͷ৔߹ɺRGAIN1-0 bits = “01”(2 steps)ʹઃఆ͓ͯ͘͠ͱɺALCϦΧόϦಈ࡞
ʹΑͬͯIVL, IVR஋͸32Hʹมߋ͞Εɺ0.75dB(0.375dB x 2)૿Ճ͞Ε·͢ɻIVL, IVR஋͕ج४Ϩϕϧ (REF7-0
bits)ʹୡͨ͠৔߹ɺIVL, IVR஋ͷ૿Ճ͸ߦ͍·ͤΜɻ
·ͨɺALCϦΧόϦ଴ػதʹ
(ϦΧόϦ଴ػΧ΢ϯλϦηοτϨϕϧ) ≤ Output Signal < (Ϧϛολݕग़Ϩϕϧ)
ͱͳ͍ͬͯΔ৔߹ɺ଴ػλΠϚ͸Ϧηοτ͞Ε·͢ɻͦͷͨΊɺ
(ϦΧόϦ଴ػΧ΢ϯλϦηοτϨϕϧ) > Output Signal
ͱͳ͔ͬͨ࣌Βɺ଴ؒ࣌ػͷΧ΢ϯτ͕։࢝͞Ε·͢ɻ
·ͨɺALCಈ࡞͸ΠϯύϧεੑͷϊΠζʹ΋ରԠͨ͠ALCʹͳ͍ͬͯ·͢ɻΠϯύϧεੑͷϊΠζ͕ೖྗ͞
Εͨ৔߹ɺ௨ৗͷϦΧόϦಈ࡞ΑΓ΋ૣ͍αΠΫϧͰϦΧόϦಈ࡞Λߦ͍·͢ɻྫ͑͹ɺϚΠΫϩϑΥϯʹ
ॠؒతʹେ͖ͳԻ͕ೖྗ͞Εͨ৔߹ɺ͜ͷಈ࡞ʹΑΓେ͖ͳԻʹຒ΋Εͨখ৴߸Λվળ͢Δ͜ͱ͕Ͱ͖·
͢ɻ
WTM1
0
0
1
1
WTM0
0
1
0
1
ALCϦΧόϦपظ
8kHz
16kHz
44.1kHz
128/fs
16ms
8ms
2.9ms
256/fs
32ms
16ms
5.8ms
512/fs
64ms
32ms
11.6ms
1024/fs
128ms
64ms
23.2ms
Table 26. ALCϦΧόϦ଴ؒ࣌ػͷઃఆ
Default
RGAIN1 RGAIN0
GAIN STEP
0
0
1 step
0.375dB
0
1
2 step
0.750dB
1
0
3 step
1.125dB
1
1
4 step
1.500dB
Table 27. ALC ϦΧόϦήΠϯྔͷઃఆ
Default
REF7-0
GAIN(dB)
Step
F1H
+36.0
F0H
+35.625
EFH
+35.25
:
:
E2H
+30.375
E1H
+30.0
0.375dB Default
E0H
+29.625
:
:
03H
−53.25
02H
−53.625
01H
−54.0
00H
MUTE
Table 28. ALCϦΧόϦಈ࡞࣌ͷج४஋ઃఆ
MS0566-J-00
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2006/11