CS6422

Telephony Network Echo Supression

Overview

Description

Most modern speakerphones use half-duplex operation, which alternates transmission between the far-end talker and the speakerphone user. This is done to ensure stability, because acoustic coupling between the speaker and microphone is much higher in speakerphones than in handsets, in which coupling is mechanically suppressed.

The CS6422 enables full-duplex conversation using echo cancellation and suppression in a single-chip solution. The CS6422 can easily replace existing half-duplex speakerphone ICs with a significant increase in conversation quality.

The CS6422 consists of telephone and audio interfaces, two CODECs and an echo-cancelling DSP.

Features

Telephony Network Echo Cancellation

• Network-only mode with acoustic echo-canceller disabled
• Configurable side-tone allows for predictable behavior even under time-variant echo
• Configurable for automatic engage/disable/re-engage of network echo-cancellation
• The cancellation and optional additional suppression of telephone network interface related echo may be achieved with the CS6422. The analog-in analog-out nature of the I/O for the CS6422 with its programmable analog gain stages and embedded, richly configurable echo-cancelling DSP with features especially tailored for the network interface and its varied echo scenarios makes it a compelling solution for applications where an acoustic echo is not present.

Full-Duplex Speakerphone

• Single-chip, full-duplex, hands-free operation
• Optional Tx noise guard
• Programmable attenuation during double-talk
• Optional 34 dB microphone pre-amplifier
• Acoustic-only mode with network echo-canceller disabled

Enhanced Echo-Canceller IC for Telephony Network Echo/Full-Duplex Speakerphone Applications

• Dual (speech-trained - telephony network and acoustic) echo cancellers
• 63.5 ms of net cancellation configurably apportionable to acoustic/network echo
• Dual optional supplementary echo suppression
• Dual volume controls with automatic gain control (AGC) and mute
• Dual integrated 80 dB IDR CODECs with programmable analog gain
• Configurable half-duplex training mode among other rich configuration options
• Power-down mode
• Microcontroller interface
• Package: 20-pin SOIC; lead-free assembly

Diagram