User Manual

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MAX98089
Low-Power, Stereo Audio Codec
with FlexSound Technology
Table 6. Record Path Signal Processing Registers (continued)
REGISTER BIT NAME DESCRIPTION
0x3F
3
AGCATK
AGC Attack Time
Defined as the time required to reduce gain by 63% of the total gain reduction (one time
constant of the exponential response). Attack times are longer for low AGC threshold
levels. See Figure 12 for details.
00 = 2ms
01 = 7.2ms
10 = 31ms
11 = 123ms
2
1
AGCHLD
AGC Hold Time
The delay before the AGC release begins. The hold time counter starts whenever the sig-
nal drops below the AGC threshold and is reset by any signal that exceeds the threshold.
Set AGCHLD to enable the AGC circuit. See Figure 12 for details.
00 = AGC disabled
01 = 50ms
10 = 100ms
11 = 400ms
0
0x40
7
ANTH
Noise Gate Threshold
Gain is reduced for signals below the threshold to quiet noise. The thresholds are relative
to the ADC’s full-scale output voltage.
6
VALUE
THRESHOLD
(dBFS)
VALUE
THRESHOLD
(dBFS)
0x0 Noise gate disabled 0x8 -45
0x1 Reserved 0x9 -41
5
0x2 Reserved 0xA -38
0x3 -64 0xB -34
0x4 -62 0xC -30
4
0x5 -58 0xD -27
0x6 -53 0xE -22
0x7 -50 0xF -16
3
AGCTH
AGC Threshold
Gain is reduced when signals exceed the threshold to prevent clipping. The thresholds
are relative to the ADC’s full-scale voltage.
2
VALUE
THRESHOLD
(dBFS)
VALUE
THRESHOLD
(dBFS)
0x0 -3 0x8 -11
0x1 -4 0x9 -12
1
0x2 -5 0xA -13
0x3 -6 0xB -14
0x4 -7 0xC -15
0
0x5 -8 0xD -16
0x6 -9 0xE -17
0x7 -10 0xF -18