M65845AFP Datasheet, PDF (7/15 Pages) Mitsubishi Electric Semiconductor – DIGITAL ECHO WITH MICROPHONE MIXING CIRCUIT

M65845AFP _{PRELIMINARY Nsootmicee}
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DIGITAL ECHO WITH
MITSUBISHI SOUND PROCESSOR
MICROPHONE MIXING CIRCUIT
ICs
FUNCTION DESCRIPTION
(1) Microphone amplifier
The gain(Gv) and low cut-off frequency(fcl) of microphone amplifier are expressed
as follows.
Gv=20log• ^R1+1.5K+334K
R1+1.5K
fcl=
1
2π•(R1+1.5K)•C1
MIC
Gv(max)=47dB,fcl=50Hz
R1=0Ω,C1=2.2µF
Assuming Gv=37dB, fcl=15Hz,for instance,
the constants take the following values.
R1=3.3KΩ,C1=2.2µF
1µF
2
5kΩ
REF
10kΩ(typ)
334kΩ
1.5kΩ
3
4
R1
C1
<< Attention point when M65845FP is replaced with M65845AFP >>
R3 and C4 are required for the
M65845FP, not for the M65845AFP.
MIC
As mentioned above, the gain of
microphone amplifier can set it up
with R1.
1µF
2
R2
REF
10kΩ(typ)
3
4
C4
R3 and C4 are not required for
the M65845AFP.
R1 for the gain of microphone
amplifier setting in use M65845AFP
R3
R1
C1
Recommended circuit In use M65845FP
MITSUBISHI
ELECTRIC
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