Browse Prior Art Database

AUTOMATED TECHNIQUE TO MEASURE AUDIO SYSTEM ACCESS TIMES

IP.com Disclosure Number: IPCOM000007363D
Original Publication Date: 1995-Mar-01
Included in the Prior Art Database: 2002-Mar-19
Document File: 1 page(s) / 74K

Publishing Venue

Motorola

Related People

David Hughes: AUTHOR [+2]

Abstract

Often it is necessary to measure the response of audio channels in a communication system. Response is usually measured by calculating how much audio truncation and audio buffering is being done by the communication equipment. Truncation is the amount of audio (usually given in l/1000 of a second incre- ment) lost in a given transmission. Buffering is the amount of audio stored and later forwarded through the channel. These measurements are not only use- ful in describing system performance, often they are required by customers and specified in contractual documents.

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MOTOROLA Technical Developments Volume 24 March 1995

AUTOMATED TECHNIQUE TO MEASURE AUDIO SYSTEM ACCESS TIMES

by David Hughes and Ken Koldan

INTRODUCTION:

PURPOSE:

  Often it is necessary to measure the response of audio channels in a communication system. Response is usually measured by calculating how much audio truncation and audio buffering is being done by the communication equipment. Truncation is the amount of audio (usually given in l/1000 of a second incre- ment) lost in a given transmission. Buffering is the amount of audio stored and later forwarded through the channel. These measurements are not only use- ful in describing system performance, often they are required by customers and specified in contractual documents.

  The method used to calculate these figures is straightforward. As an example, measurements were taken as shown in Figure 1. Time '0' is usually radio Push-To-Talk. A known amount of audio is sent (in this example 1 second of audio) through the chan- nel. The audio truncation amount is equal to the amount of audio sent minus the amount of audio received. The audio buffering amount is equal to the system throughput (time from Push-To-Talk to audio present on the channel output) minus the audio truncation amount. In our example,

audio truncation = 1000 ms - 750 ms

= 250 ms.

audio buffering = 400 ms - 250 ms

= 150 ms.

  Historically these types of measurements are made using two main pieces of test equipment: a digital storage oscilloscope and a burst oscillator. The channel would be activated, the audio burst would be generat...