BD3870FS ROHM Co. Ltd., BD3870FS Datasheet - Page 11

• Manufacturer Part Number: BD3870FS
• Description: Audio Sound Processor For Home Audio
• Manufacturer: ROHM Co. Ltd.

2)
3)
Treble filter
Matrix surround
In-phase Gain: Gains obtained on OUT1 and OUT2 against IN1 when inputting a signal of the equivalent level and
Matrix surround is constructed as shown above. Gains are defined as follows:
in-phase (L=R) to IN1 and IN2.
Single-phase Gain: Gains obtained on OUT1 and OUT2 against IN1 when inputting a signal to IN1 and AC-grounding
IN2 (R=0).
Opposite-phase Gain: Gains obtained on OUT1 and OUT2 against IN1 when inputting signals of the equivalent level
and opposite-phase (L-R) to IN1 and IN2.
Standard values of R1, R2 (reference)
* The actual boost cut amount may deviate from the standard values in some degree.
Treble Boost Cut Amount
14dB (BD3872FS only)
OUT2
OUT1
OUT1
OUT1
IN1
IN1
IN1
IN1
IN
=
=
=
=
10dB
12dB
0dB
2dB
4dB
6dB
8dB
OUT2
OUT2
−
4.14
IN2
IN2
2
2.14
Fig.7
2
L
L
R
L
R2
=
=
C
L
IN1
IN2
+
-
⎛
⎜
⎝
⎛
⎜
⎝
L
=
R1
4.14
4.14
2
2
=
2,07
×1/2
×1/2
−
L
L
1.07
Resistance (kΩ) * Typ.
OUT
−
+
2.14
2.14
13.39
18.10
21.84
24.81
27.20
29.04
+
7.46
2
2
R1
+
-
0
L
L
⎞
⎟
⎠
⎞
⎟
⎠
×2.14
L
L
Fig.9
=
=
11/16
1
3.14
36.28
28.82
22.89
18.18
14.44
11.47
9.08
7.24
R2
+
+
+
+
-
+
(4.14R/2-2.14L/2)
(4.14L/2-2.14R/2)
20log1 =
20log
20log3.14 =
20log2.07 =
fc =
G (boost) = 20log
G (cut) = 20log
Zc =
OUT2
OUT1
−
2πR2C
1.07
jωc
0
1
1
G
10
6.3
=
(dB)
(Ω)
0.59
3dB
3dB
R1+R2+Zc
(Hz)
(dB)
(dB)
R2+Zc
R1+R2+Zc
R2+Zc
(dB)
Fig.8
ｆc
(dB)
(dB)
G
G
ｆ