adav802 Analog Devices, Inc., adav802 Datasheet - Page 14

• Manufacturer Part Number: adav802
• Description: Audio Codec For Recordable Dvd
• Manufacturer: Analog Devices, Inc.

ADAV802
Recovery and Normal Recovery Modes. If the output level of
the ADC exceeds the Attack Threshold then Attack Mode is
initiated. When Attack Mode has reduced the PGA gain to
suitable levels the ALC will attempt to recovery the gain to its
original level. If the ADC output level exceeds the level set by
the Recovery Threshold bits a counter is incremented
(GAINCNTR). This counter is incremented, at intervals equal
NO
INCREASE GAIN BY 0.5dB
WAIT RECOVERY TIME
FULLY RESTORED?
HAS GAIN BEEN
YES
YES
LIMITED RECOVERY
BELOW RECOVERY
WAIT FOR SAMPLE
ABOVE ATTACK
THRESHOLD?
THRESHOLD?
IS SAMPLE
IS SAMPLE
NO
YES
IS A RECOVERY
MODE ENABLED?
AT MAXIMUM?
IS GAINCNTR
INCREMENT
NO
YES
RECOVERY
GAINCNTR
WAIT
TIME
NO
Figure 6. ALC Flow Diagram
NO
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ATTACK MODE
DECREASE GAIN BY 0.5dB
GREATER THAN ATTACK
AND WAIT ATTACK TIME
NO
WAIT FOR SAMPLE
THRESHOLD?
IS SAMPLE
NO
to the Recovery Time selection, if the ADC has any excursion
above the Recovery Threshold. If the counter reaches its
maximum value, determined by the GAINCNTR bits in ALC
Control Register 1, the PGA gain is deemed suitable and no
further gain recovery is attempted. If, at any time, the ADC
output level exceeds the Attack Threshold, Attack Mode is
reinitiated and the counter is reset
YES
INCREASE GAIN BY 0.5dB
WAIT RECOVERY TIME
FULLY RESTORED?
BELOW RECOVERY
WAIT FOR SAMPLE
ABOVE ATTACK
HAS GAIN BEEN
THRESHOLD?
THRESHOLD?
IS SAMPLE
NORMAL RECOVERY
IS SAMPLE
YES
NO
Preliminary Technical Data
RECOVERY
WAIT
TIME
NO
YES