W681307 Datasheet, PDF (101/160 Pages) Winbond – USB1.1 CODEC Microprocessor Control Unit with 32KB Mask ROM and 4KB RAM

W681307
13.4.6.4
Address
0x14EA
NS_Active_Power_LSB
Access Mode Value At Reset Nominal Value
R/W
0x00
0x40
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
NS_Active_Power_LSB
The most significant byte of noise threshold.
So "noise_threshold" = {NS_Active_Power_MSB,NS_Active_Power_LSB}
13.4.7
AEC Soft Clip
In order to reduce clipping distortion, a soft clipping function has been implemented in GTx1. A second gain (GTx1_SC) and an overload
： ^{threshold point (TH_SC) is programmable. Gain GTx1 is changed to GTx1_SC if the input signal level of the GTx1 gain state is greater}
than TH_SC. Note that the input signal power level is estimated in the GTx1 gain stage using the following arithmetic unit
( ) ^P_GTx1 ^{= P}_GTx1 ^{× 1 − 2 GTx1_TC−16 + A}_GTx1 ^{× 2GTx1_TC−16}
If
( P_GTx1 ≥ TH_SC)
GTx1_ Factor ⇐ GTx1_ SC
Else GTx1_ Factor ⇐ GTx1
GTx1_avg ⇐ (1 − 2 ^{(GT _TC−16)} ) × GTx1_avg + GTx1_ Factor × 2^{(GT _TC−16)}
A_rin ⇐ A_GTx1 × GTx1_avg
： P_GTx1 GTx1 input power with time constant GTx1_TC
： GTx1_avg GTx1 average gain with time constant GT_TC
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Publication Release Date: May, 2007
Revision 1.3