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AK4645AEZ Datasheet, PDF (37/85 Pages) Asahi Kasei Microsystems – Stereo CODEC with MIC/HP-AMP | |||
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[AK4645A]
2. ALCϦΧÏϦà²à¡
ALCϦΧÏϦà²à¡Í¸ÉºWTM2-0Í°àªà°ÍÎͨà£Ø(Table 24)଴ػÎߦÍɺÍÍ·Øɺà¥à¾à§´ß¸ÍALCϦΧÏϦ଴
ػΧ΢ϯλϦηοÏϨÏϧ(Table 21)Îӽ͢ÍͱÍͳÍÎ͹ALCϦΧÏϦà²à¡ÎߦÍÎ͢ɻÍÍ·ALCϦΧÏϦ
à²à¡Í¸àªà°ÍÎͨج४ϨÏϧ(Table 26) ÎÍ°ZTM1-0 bitsÍ°àªà°Í ͨà£Ø(Table 23)ͰθϩΫϩεÝà¥à²à¡Îߦ
ÍͳÍÎɺRGAIN1-0 bitsÍ°àªà°Í ͨà®(Table 25)Í©ÍIVL, IVRà®(L/RÚ௨)Îà£à²à°¤Í´à«¿ÕÍͤÎ͢ɻÍÍ·ALC
ϦΧÏϦà²à¡Í¸WTM2-0 bitsÍ°àªà°Í ͨपߦͰظÎÎÎÍ¢É»Í¨Í©Í ÉºWTM2-0 bitsÍ°Í·àªà°ÎÎZTM1-0 bits
Í°Í·àªà°Íà¯Íà§ß¹Í´ÍÍͯɺ৴߸ÍÎ¸Ï©Î«Ï©ÎµÍ Í³ÍͱÍʹ͸ɺZTM1-0 bitsÍ·àªà°Í°ALCϦΧÏϦà²à¡Í
ߦÎÎÎ͢ɻ
ྫÍ͹ɺà¡Ý±Í·IVL, IVRà®Í30HÍ·à§ß¹ÉºRGAIN1-0 bits = â01â(2 steps)Í´àªà°Í ͯÍÍͱɺALCϦΧÏϦà²à¡
Í´ÎͬͯIVL, IVRà®Í¸32HʹมßÍÎɺ0.75dB(0.375dB x 2)à«¿ÕÍÎÎ͢ɻIVL, IVRà®Íج४ϨÏϧ (REF7-0
bits)Í´à¡Í ͨà§ß¹ÉºIVL, IVRà®Í·à«¿Õ͸ߦÍÎͤÎÉ»
ÎͨɺALCϦΧÏϦ଴ػதʹ
(ϦΧÏϦ଴ػΧ΢ϯλϦηοÏϨÏϧ) ⤠Output Signal < (ϦÏολÝà¥Ï¨Ïϧ)
ͱͳͬͯÍÎà§ß¹Éºà¬´Ø»Î»Î Ï͸ϦηοÏÍÎÎ͢ɻͦͷͨÎɺ
(ϦΧÏϦ଴ػΧ΢ϯλϦηοÏϨÏϧ) > Output Signal
ͱͳͬͨà£ÍÎɺ଴Øà£Ø»Í·Î§Î¢Ï¯ÏÍÖà¢ÍÎÎ͢ɻ
ÎͨɺALCà²à¡Í¸Î ϯÏϧεà©Í·ÏΠζʹÎà¬°Ô Í Í¨ALCʹͳͬͯÍÎ͢ɻΠϯÏϧεà©Í·ÏΠζÍà³à¾Í
Îͨà§ß¹Éºà¯¨à§Í·Ï¦Î§ÏϦà²à¡ÎÎÎà«£ÍαΠΫϧͰϦΧÏϦà²à¡(ÏÎÊεÏϦΧÏϦà²à¡)ÎߦÍÎ͢ɻ
ྫÍ͹ɺÏΠΫϩÏΥϯʹॠØతʹàÍͳԻÍà³à¾ÍÎͨà§ß¹ÉºÍÍ·à²à¡Í´ÎÎàÍͳԻʹàºÎÎͨà¦à§´ß¸
Îվળ͢ÎÍͱÍÍ°ÍÎ͢ɻÏÎÊεÏϦΧÏϦà²à¡Í·à¬Í͸ɺRFST1-0 bits Í´ÎÎàªà°Í ÎÍ¢(Table 27)É»
WTM2
0
0
0
0
1
1
1
1
WTM1
0
0
1
1
0
0
1
1
WTM0
ALCϦΧÏϦपظ
8kHz
16kHz
44.1kHz
0
128/fs
16ms
8ms
2.9ms
1
256/fs
32ms
16ms
5.8ms
0
512/fs
64ms
32ms
11.6ms
1
1024/fs
128ms
64ms
23.2ms
0
2048/fs
256ms
128ms
46.4ms
1
4096/fs
512ms
256ms
92.9ms
0
8192/fs
1024ms
512ms
185.8ms
1
16384/fs
2048ms
1024ms
371.5ms
Table 24. ALCϦΧÏϦ଴Øà£Ø»Í·àªà°
(default)
RGAIN1 RGAIN0
GAIN STEP
0
0
1 step
0.375dB (default)
0
1
2 step
0.750dB
1
0
3 step
1.125dB
1
1
4 step
1.500dB
Table 25. ALC ϦΧÏϦήΠϯà¾Í·àªà°
MS0986-J-00
- 37 -
2008/07
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