MB86434 Datasheet, PDF (22/38 Pages) Fujitsu Component Limited. – 5V Single Power Supply Audio Interface Unit (AIU)

MB86434
4. Receiver Connections
It is possible to add tones and adjust sidetones by using amp 1,2 and 3 and the electronic volume control. When
using amp 3, however, it is necessary to include HPF to avoid interference from the speaker amp DC.
• Tone and Sidetone Addition by Inclusion of Secondary LPF and Primary HPF.
SGC
SGC
R1
R2
IM1
C1
C2 C3
PTBO
(receiving)
–
+
AMP1 OP1
OP1
R3
R4 R5
SGC
C3
IM2 R6
OP2
–
+
AMP2
R7 C4
TONEO (tone)
BBO (sidetone)
Secondary LPF
A = –R 2/R 3
ω/Q = 1/C 2* (1/R 1 +1/R 2 +1/R 3)
ω 2 = 1/ (R 1 R 3 C 1 C 2)
Signal addition
R 4 = R 5 = R 6 = R 7 = 100 kΩ
C 3 = C 4 = 0.1 µF
EV2
BTO
SGC
IM3
BBI
–
+
AMP3
(inside IC)
• Amp1, Amp2 not used
C5
R8
R9
C6
IMTON
Primary HPF
A = –R 9/R 8
f c = 1/(2πC 5 R 8)
C 6 = 0.1 µF
The following settings are
necessary to comply with CCITT
Recommendation
R 8 = R 9 = 100 kΩ
C 5 = 0.039 µF
IM1
SGC
+
AMP1
OP1
(inside IC)
IM2
SGC
+
AMP2
OP2
EV2
BTO
(inside IC)
open
Note: When amps are not used, the amp input and output should be shorted together.
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