Texas Instruments Boomer LM49360, Руководство пользователя

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TABLE 70. ADC_ALC_1 (0x81h)
Bits Field Description
2:0 ADC_SAMPLE This programs the timers on the ALC with the closest sample rate of the ADC.
ADC_SAMPLE Expected ADC f
S
000 8kHz
001 12kHz
010 16kHz
011 24kHz
100 32kHz
101 48kHz
110 96kHz
111 192kHz
3 LIMITER If set, the circuit will never apply gain to the signal, no matter how small, but it will attenuate the
signal as soon as it reaches target and release it at the decay rate, once signal level reduces below
target. The I
2 C gain setting (at the time the LIMITER is enabled) is the maximum gain that the ALC
will apply. Care should be taken when choosing the optimum I 2 C gain setting whenever enabling
the Limiter.
4 STEREO LINK If set, the ALC circuit uses the stereo average of the input signals to control the gain of the stereo
output. This maintains stereo imaging. If this bit is cleared, then both channels operate as dual
mono.
5 SOURCE_RSEL If both SOURCE_OVR and this bit is set, the right ADC ALC channel will be active.
6 SOURCE_LSEL If both SOURCE_OVR and this bit is set, the left ADC ALC channel will be active.
7 SOURCE_OVR If set, the active channel of the ADC ALC is determined by SOURCE_RSEL and SOURCE_LSEL.
If cleared, the active channel of the ADC ALC is determined by the selected input to the ADC.
MONO enables left ALC, AUX enables right ALC, MIC enables left and / or right ALC depending
on which ADC channel MIC is selected to.
TABLE 71. ADC_ALC_2 (0x82h)
Bits Field Description
3:0 NOISE_FLOOR This sets the anticipated noise floor. Signals lower than the noise floor specified will be gated from
the ALC to avoid noise pumping.
NOISE_FLOOR Noise Floor (dB)
0000 –39
0001 –42
0010 –45
0011 –48
0100 –51
0101 –54
0110 –57
0111 –60
1000 –63
1001 –66
1010 –69
1011 –72
1100 –75
1101 –78
1110 –81
1111 –84
4 NG_ENB This enables the Noise Gate.
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LM49360