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SERVICE FOR A RADIO USER RECEIVING A SIGNAL TO CONTROL THE AUDIO PREFERENCE SETTINGS OF A TRANSMITrING RADIO

IP.com Disclosure Number: IPCOM000009671D
Original Publication Date: 2000-Jan-01
Included in the Prior Art Database: 2002-Sep-10
Document File: 3 page(s) / 139K

Publishing Venue

Motorola

Related People

Andrew Aftelak: AUTHOR [+2]

Abstract

A service is offered to a listener, using a receiv- ing two-way radio, that allows the listener to change the characteristics of the speech signal by control- ling the audio processing components in the trans- mitting radio.

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0 M MOTOROLA Technical Developments

SERVICE FOR A RADIO USER RECEIVING A SIGNAL TO CONTROL THE AUDIO PREFERENCE SETTINGS OF A TRANSMITrING RADIO

by Andrew Aftelak and David Pearce

ABSTRACT

  A service is offered to a listener, using a receiv- ing two-way radio, that allows the listener to change the characteristics of the speech signal by control- ling the audio processing components in the trans- mitting radio.

INTRODUCTION

  This paper describes improvements in the fields of two-way radio, cellular telephony and other audio based communication systems. In particular, this paper concerns perceived audio quality in comnumi- cation between two remotely located entities.

PROBLEMS TO BE SOLVED

  In traditional FM radios, and more so in radios using compressed digital speech, the design of a radio involves making choices about the set-up of the audio path.

  In addition to the adjustment of volume, the speech heard from a receiving radio can be affected by various processing stages in the audio path. These include setting of the spectral balance, inclu- sion of noise suppression techniques, and non-linear processing techniques to change the artifacts in syn- thesized speech. There is no optimum combination of these processing blocks in the audio path, because the situation in which the radio is used and the user's preferences are paramount.

  It would be possible to provide the radio user with controls on his/her radio to alter the way the speech sounds, e.g. a tone control. However, due to the inherent non-linearity of digital speech codecs and some digital processing algorithms, operations carried out at the transmitter cannot easily be

reversed (or "undone") by post-processing in the receiver.

  A new service is required which can provide the listener with further enhanced quality of received speech.

PROPOSED SOLUTION TO THE PROBLEMS

  The solution of the present proposal allows the listener of a two-way radio to set up the audio path as he/she prefers. The service offered to the listener allows the listener to change the characteristics of the speech signal by controlling the audio process- ing components in the transmitting radio.

  The radios may be operating in 'direct mode' or in a 'trunked' system. The listener may change the set-up of the transmitting radio in real time or near- real time. The listener may control one or many of the audio processing blocks in the transmitter. The most useful functions that may be controlled in the transmitting radio are those that are difficult to reverse or "undo" in the receiving radio.

Examples of these are:

  l spectral shaping (linear filtering) prior to a dig- ital codec in the transmitter

l any non-linear processing in the transmitter

  l audio (background) noise suppression in the transmitter

l the set up of the vocoder.

  Instigation of the service may be by exchange of signaling information, which may require authenti- cation of the receiving radio's privilege to access the

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