M65856SP Datasheet, PDF (13/17 Pages) Mitsubishi Electric Semiconductor – DIGITAL ECHO WITH MICROPHONE MIXING CIRCUIT

MITSUBISHI SOUND PROCESSOR ICs
M65856SP
DIGITAL ECHO WITH MICROPHONE MIXING CIRCUIT
(5)ALC level diagram
Vo(dBV)
10
+3
0
-10
-20
-30
ALC OPERATING VOLTAGE SETTING RANGE
MICROPHONE AMPLIFIER GAIN SETTIG=47dB
-70 -60 -50 -40 -30 -20 -10
Vi(dBV)
(6)ALC operating voltage setting
ALC operating voltage can be set at a desired value between -10dBV and +3dBV by varying
the DC voltage applied to pin 3 (ALC operating voltage setting terminal).
(Setting method)
1
2.5V( 2 Vcc)
INTERNAL DC BIAS
ONE SIDE
PEAK VOLTAGE,Vpo
VOLTAGE APPLIED TO 35 PIN,VALC
1
OV
VALC= ₂ Vcc-Vpo
To set ALC operating voltage at -5dB(Vcc=5V)
Vcc
-5dBV=0.56Vrms=1.59Vp-p=0.8Vp-o
VALC=2.5-0.8=1.7V
51k
3_•
R
Since the input impedance at pin 5 10 is high at 1MΩ or more,
it is possible to provide ALC operating voltage by dividing resistance.
0.01µ
When Vcc=5V
ALC operating
voltage (dBV)
+3
0
-2
-4
-6
-8
-10
Voltage applied to
pin 5 10 VALC(V)
0.50
1.09
1.38
1.61
1.79
1.94
2.05
Resistance R(Ω)
5.6k
15k
20k
24k
27k
33k
36k
MITSUBISHI
ELECTRIC