A G711/G722 Front End Circuit for High Quality Handsfree Telephony

This paper presents the architecture and implementation of an analog-to-digital front end circuit developed for an enhanced quality handsfree telephone terminal, including digital acoustic echo cancellation. This circuit has been implemented in a 1 ¿m analog CMOS process and the design has been optimized using efficient analog and digital silicon generators. As a result, the SNR of each chain is better than 87 dB and the circuit has a total power dissipation of less than 80 mW. Measured results are also presented.