Browse Prior Art Database

ASTRO AUDIO TONE GENERATION BY FIELD UNITS

IP.com Disclosure Number: IPCOM000008410D
Original Publication Date: 1997-Dec-01
Included in the Prior Art Database: 2002-Jun-12
Document File: 2 page(s) / 101K

Publishing Venue

Motorola

Related People

Bradley A. Johnson: AUTHOR

Abstract

Motorola's ASTRO technology has improved audio quality over a larger section of the coverage area than was achieved in the analog mode of oper- ation, In order to get this improvement in a digital transmission with the fewest number of bits, a vocoder has been used. The vocoders used today (both VSELP and IMBE) in ASTRO are designed for the smallest components of the human voice. As a result, audio that is not made up of the same com- ponents as the human voice, when vocoded, become distorted. Motorola customers use several audio tones as a method of communications over Radio Frequency channels. These same customers (and new ones) will want to and do use the same audio tones over ASTRO channels.

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m MOTOROLA Technical Developments

ASTRO AUDIO TONE GENERATION BY FIELD UNITS

by Bradley A. Johnson

BACKGROUND

  Motorola's ASTRO technology has improved audio quality over a larger section of the coverage area than was achieved in the analog mode of oper- ation, In order to get this improvement in a digital transmission with the fewest number of bits, a vocoder has been used. The vocoders used today (both VSELP and IMBE) in ASTRO are designed for the smallest components of the human voice. As a result, audio that is not made up of the same com- ponents as the human voice, when vocoded, become distorted. Motorola customers use several audio tones as a method of communications over Radio Frequency channels. These same customers (and new ones) will want to and do use the same audio tones over ASTRO channels.

THE PROBLEM

  Dispatch Consoles have several unique Audio Alert Tones. These tones are used to alert field units of the importance of the impending voice message and that their attention is required. These tones are distorted considerably due to the vocoding process. Other audio signals are used by the system to inform the radio user of conditions. For example, during a telephone interconnect call a radio user can be informed that the telephone line is available with

a "Dial Tone." The user can be informed of other conditions with "Busy Signal," "Ringing Tone," and other tones. All of these tones are sent as analog

tones through the ASTRO system and as a result of them not being voice components, are distorted by the vocoding process.

SOLUTION

  The ASTRO signal has available several digital words set aside for signaling. This invention will use some unused signaling words to inform the field unit of the alert tone or other signal. The field unit would then be able to generate its own tone for the appropriate non-voice signal(s). The ASTRO sys- tem would not try to vocode a tone but rather send an ASTRO signal word in the digital format. Other signal tones are generated by the field units already like "Out of Range, " "trunk busy" and "trunk talk permit."

DISPATCH CONSOLE

  In the case of the Dispatch Console, the Disp...