BU9409FV_12 Datasheet, PDF (37/58 Pages) Rohm – 32bit Audio DSP

BU9409FV
Technical Note
4-22. Sub output 3 band Parametric Equalizer
The peaking filter or the low shelf filter or the high shelf filter can be used by the parametric equalizer of 3 bands. By the fact
that F, Q and Gain are selected, it converts the setting to the coefficient (b0, b1, b2, a1 and a2) of the digital filter inside IC,
and transfers it to the coefficient RAM. There is no smooth transition function.
Band1 Band2 Band3
Level
±18dB
f
(0.5dB step)
Selection of filter type
Default = 0
63
80
100
Select Address
bit[ 7:6 ]
It sets to all band
Value
0
1
2
Peaking filter
Low shelf filter
High shelf filter
(Hz)
Operating explanation
Transfer start setting to coefficient RAM.
It transfers directly to coefficient RAM.
Default = 0
Select Address
bit [ 0 ]
It sets to all band
Value
0
1
Operating explanation
Coefficient transmission stop
Coefficient transmission start
Selection of frequency (F₀)
Default = 0Eh
Select
Operating explanation
Address
bit [ 5:0 ]
It sets to all
band
Command Frequency Command Frequency Command Frequency Command Frequency Command Frequency Command Frequency Command Frequency Command Frequency
00
20Hz
08
50Hz
10 125Hz 18 315Hz 20 800Hz 28
2kHz
30
5kHz
38 12.5kHz
01
22Hz
09
56Hz
11 140Hz 19 350Hz 21 900Hz 29 2.2kHz 31 5.6kHz 39 14kHz
02
25Hz
0A
63Hz
12 160Hz 1A 400Hz 22
1kHz
2A 2.5kHz 32 6.3kHz 3A 16kHz
03
28Hz
0B
70Hz
13 180Hz 1B 450Hz 23 1.1kHz 2B 2.8kHz 33
7kHz
3B 18kHz
04
32Hz
0C
80Hz
14 200Hz 1C 500Hz 24 1.25kHz 2C 3.15kHz 34
8kHz
3C 20kHz
05
35Hz
0D
90Hz
15 220Hz 1D 560Hz 25 1.4kHz 2D 3.5kHz 35
9kHz
3D
-
06
40Hz
0E 100Hz 16 250Hz 1E 630Hz 26 1.6kHz 2E
4kHz
36 10kHz 3E
-
07
45Hz
0F 110Hz 17 280Hz 1F 700Hz 27 1.8kHz 2F 4.5kHz 37 11kHz 3F
-
Selection of quality factor (Q)
Default = 4h
Select Address
bit [ 3:0 ]
It sets to all band
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Operating explanation
Command
0
1
2
3
4
5
6
7
Quality factor
0.33
0.43
0.56
0.75
1.0
1.2
1.5
1.8
Command
8
9
A
B
C
D
E
F
Quality factor
2.2
2.7
3.3
3.9
4.7
5.6
6.8
8.2
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2012.03 - Rev.A