BU9414FV Datasheet, PDF (16/61 Pages) Rohm – 32bit Audio DSP

BU9414FV
Technical Note
4-4. P²Volume （Perfect Pure Volume）
There are some scenes in which sound suddenly becomes large like plosive sound in TV Commercial or Movie.
P²Volume function automatically controls the volume and adjusts the output level.
In addition, it also adjusts in such a way that a whispery sound can be heard easily.
P²Volume function operates in the fields of (1), (2) & (3) divided according to input level.
(1) at the time of V_Ｉinf(-∞)～V_Ｉmin
V_O
Noise is prevented from being lifted by P²Volume function.
(2) When input level is over V_Ｉmin and output is below V_Omax
V_O = V_I + α
α： Lifting the Whole output level by the offset value α
(3) When output level Ｖ_Ｏ exceeds V_Omax
V_Omax
P2V_MAX
V_O = K・V_I + α
(2)
K： Slope for suppressing of D range （P2V_K）
It is also possible to set an output level constant.
V_Omin
α
Selection of using the P²Volume function.
Default = 0
Select Address
&h33 [ 7 ]
Value
0
1
V_Oinf
V_Iinf
(1)
V_Imin
P2V_MIN
Operational explanation
Not using the P²Volume function
Using the P²Volume function
P2V off
K
(3)
0dB
V_I
Setting of V_Ｉmin
In order to cancel that noise etc. is lifted by P²Volume, the P2V_MIN sets the minimum level at which (to the minimum) the
P²Volume functions.
command
Default = 00h
Select Address
&h34 [ 4:0 ]
command
00
01
02
03
04
05
06
07
gain
-∞
-30dB
-32dB
-34dB
-36dB
-38dB
-40dB
-42dB
command
08
09
0A
0B
0C
0D
0E
0F
Operational explanation
gain
-44dB
-46dB
-48dB
-50dB
-52dB
-54dB
-56dB
-58dB
command
10
11
12
13
14
15
16
17
gain
-60dB
-62dB
-64dB
-66dB
-68dB
-70dB
-72dB
-74dB
コマンド値
18
19
1A
1B
1C
1D
1E
1F
ゲイン
-76dB
-78dB
-80dB
-82dB
-84dB
-86dB
-88dB
-90dB
Setting of V_Ｏmax
P2V_MAX sets the output suppression level. It represents the output level V_Ｏmax at the time of input level V_I = 0dB in the
case of setting of P2V_K = “0h”（slope is 0）.
Default = 00h
Select Address
&h35 [ 4:0 ]
command
00
01
02
03
04
05
06
07
gain
0dB
-1dB
-2dB
-3dB
-4dB
-5dB
-6dB
-7dB
Operational explanation
command
08
09
0A
0B
0C
0D
0E
0F
gain
-8dB
-9dB
-10dB
-11dB
-12dB
-13dB
-14dB
-15dB
command
10
11
12
13
14
15
16
17
gain
-16dB
-17dB
-18dB
-19dB
-20dB
-21dB
-22dB
-23dB
command
18
19
1A
1B
1C
1D
1E
1F
gain
-24dB
-25dB
-26dB
-27dB
-28dB
-29dB
-30dB
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2012.03 - Rev.A