VOICE SWITCHED SPEAKER-PHONE CIRCUIT
The UTC MC34018 speaker-phone integrated circuit includes all
the active circuitry and control functions to implement a high quality
hands-free telephone system. The circuit includes a microphone
amplifier, a speaker amplifier, level detectors, a background sound
level monitoring system in both the transmit and receive channels
and an attenuation system which can control the transmit and
receive levels as well as the background level.
The applications include household and office speaker-phones,
intercom systems, hand free kit for mobile phones, and others.
* Chip Select pin for Power conservation (active/standby mode).
* Integrated all necessary active circuitry for a hand-free telephone into one single chip.
* Operating under wide dynamic range through signal compression technology.
* Build-In voltage regulators illuminate external regulators for lining operation.
* Monitoring system for background noise level.
* Background sound level compensation for transmit and receive levels as well as the background level.
* Power audio amplifier for typical 100mW output (into 25Ω) with peak limiting for speaker to minimize distortion.
* Volume control function for external volume control circuit.