WM9713L_06 WOLFSON [Wolfson Microelectronics plc], WM9713L_06 Datasheet - Page 30

• Manufacturer Part Number: WM9713L_06
• Description: AC 97 Audio + Touchpanel CODEC
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

WM9713L
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ATTACK (GAIN RAMP-DOWN) TIME
Attack time is the time that it takes for the PGA gain to ramp down across 90% of its range (e.g. from
27.75dB down to –15B gain). The time it takes for the recording level to return to its target value
therefore depends on both the attack time and on the gain adjustment required. If the gain
adjustment is small, it will be shorter than the attack time. The attack time can be programmed in
power-of-two (2
When operating in stereo, the peak detector takes the maximum of left and right channel peak
values, and any new gain setting is applied to both left and right PGAs, so that the stereo image is
preserved. However, the ALC function can also be enabled on one channel only. In this case, only
one PGA is controlled by the ALC mechanism, while the other channel runs independently with its
PGA gain set through the control register.
When one ADC channel is unused, the peak detector disregards that channel. The ALC function can
also operate when the two ADC outputs are mixed to mono in the digital domain, but not if they are
mixed to mono in the analogue domain, before entering the ADCs.
n
) steps, from 6ms, 12ms, 24ms, etc. to 6.14s.
PP Rev 3.0 June 2006
Pre-Production
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