TEA7532 ST Microelectronics, Inc., TEA7532 Datasheet - Page 7

• Manufacturer Part Number: TEA7532
• Description: Monitor Amplifier With Anti-larsen Function And Adjustment (full Duplex)
• Manufacturer: ST Microelectronics, Inc.

Amplifier dc supply.
In transmission mode, the supply voltage is control-
led by the internal shunt DC regulator. For this rea-
son, the TEA7532 should be supplied from a current
source
Figure 13.
Circuit action.
When the supply voltage is insufficient, the voltage
at pin 1, falls below the reference voltage 1.1 V, re-
sulting in transistor (TR) being switched off, resulting
in zero current flow in resistor R. This state enables
the gain control system. Under these conditions, the
shunt DC supply will switch at a rate determined by
the time constant of the RC network on pin 3.
This switching action accomodates normal speech
Figure 14 .
(see : supply considerations).
An antidistortion system is embodied which pro-
vides AGC control to avoid loudspeaker distortion
under current-limited conditions.
characteristics under low supply conditions.
1.2. ANTIACOUSTIC FEED-BACK SYSTEM (AN-
TILARSEN SYSTEM)
The purpose of this system is to control AGC action
in order to avoid acoustic feed-back between the
loudspeaker and the microphone, when used in a
telephone set.
TEA7532
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