Speech processor using controlled center clipping

USRE28919E · kind E · reissue

Assignee

• Bell Telephone Laboratories, Inc. · US

Inventors

• David Arthur Berkley · Summit, US
• Olga M. M. Mitchell · Summit, US
• John R. Pierce · Huntington Woods, US

Key dates

• Filing date: Oct 11, 1974
• Grant date: Jul 27, 1976
• Expiry date: Oct 11, 1994

Classification

• Technology area (CPC —): General

Abstract

An echo suppressor for full duplex telephone circuits consists of a filter bank of contiguous band filters in the transmission path, with each filter output feeding a separate center clipper. Each clipping level is controlled by echo signal amplitude as attenuated by the trans-hybrid loss that occurs in the corresponding subband. The scheme permits "double-talking" while suppressing the echo component.