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METHOD OF DETERMINING ACOUSTICAL ISOLATION TO PREVENT ECHO IN A FULL DUPLEX ENVIRONMENT

IP.com Disclosure Number: IPCOM000008456D
Original Publication Date: 1997-Dec-01
Included in the Prior Art Database: 2002-Jun-17
Document File: 2 page(s) / 100K

Publishing Venue

Motorola

Related People

Steve Hall: AUTHOR [+3]

Abstract

One of the most impacting ways to improve both product quality and production volume is to replace subjective tests with automated counter- parts One such example is a manual test performed on a two-way radio that verities correct assembly of the radio's internal microphone. With a radio operating in a full-duplex environment, it is essen- tial to have the proper amount of isolation between the microphone and earpiece. Several defects such as the microphone boot not being assembled cor- rectly to the element cause microphone sensitivity and audio anomalies, These defects can be detected by a tester placing an interconnect (phone) call, speaking into the microphone, and listening in the radio's earpiece. An echo will be heard in the radio's internal earpiece speaker if the microphone or the microphone boot is not assembed correctly. The challenge is to create an automated "echo test" to eliminate the subjective manual testing that is currently being done. This need became more urgent not only because this was a subjective test; but also because this test, being manual and time consuming in nature, hindered the implementation of an automated phone call test station. Another need was to identify microphone failures earlier in the test process as the manual verification test occurs at the last test point in the factory before the product is packed in a shipping box.

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MOTOROLA Technical Developments

METHOD OF DETERMINING ACOUSTICAL ISOLATION TO PREVENT ECHO IN A FULL DUPLEX ENVIRONMENT

by Steve Hall, Mike Boyce and Pete Chrisler

PROBLEM SOLVED BY THE INVENTION

  One of the most impacting ways to improve both product quality and production volume is to replace subjective tests with automated counter- parts One such example is a manual test performed on a two-way radio that verities correct assembly of the radio's internal microphone. With a radio operating in a full-duplex environment, it is essen- tial to have the proper amount of isolation between the microphone and earpiece. Several defects such as the microphone boot not being assembled cor- rectly to the element cause microphone sensitivity and audio anomalies, These defects can be detected by a tester placing an interconnect (phone) call, speaking into the microphone, and listening in the radio's earpiece. An echo will be heard in the radio's internal earpiece speaker if the microphone or the microphone boot is not assembed correctly. The challenge is to create an automated "echo test" to eliminate the subjective manual testing that is currently being done. This need became more urgent not only because this was a subjective test; but also because this test, being manual and time consuming in nature, hindered the implementation of an automated phone call test station. Another

need was to identify microphone failures earlier in the test process as the manual verification test occurs at the last test point in the factory before the product is packed in a shipping box.

DESCRIPTION OF THE INVENTION

  Common defects relating to the microphone assembly result in either a "dead" microphone or an "echo" failure where proper isolation between the

earpiece and the microphone is impaired. These defects can be detected by allowing both the micro- phone and earpiece to be enabled such that feed- back results. Figure 1 depicts the coupling paths that allow the radio microp...