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Method of Measuring and Compensating for Telephone Line Distortion

IP.com Disclosure Number: IPCOM000034468D
Original Publication Date: 1989-Feb-01
Included in the Prior Art Database: 2005-Jan-27

Publishing Venue

IBM

Related People

Authors:
Locke, ME [+details]

Abstract

As users of voice store and forward equipment require more flexible transmission of messages, it has become necessary to transmit messages between remote equipment. For example, a corporation may have large offices in New York and Los Angeles and desire transmission of voice messages between these two sites. The amount of amplitude distortion (non-flat frequency response) on such lines is variable. Substantial roll-off of the high frequencies (greater than 2 kHz) can cause a serious reduction in intelligibility (in normal 2 way telecommunications, users can interact to make such line acceptable). Substantial rolloff of the low frequencies (less than 1 kHz) can cause user perceived message quality to suffer. A frequency response equalizer (or just equalizer) is generally used to correct for amplitude distortion.