dvsi hx-sd™ selectable mode vocoder

The Speech Compression SpecialistsDIGITAL VOICE SYSTEMS, INC.

DVSI HX-SD™ Selectable Mode Vocoder

Digital Voice Systems, Inc.One Van de Graaff Drive

Burlington, MA 01803 USAPhone: (781) 270-1030

Fax: (781) 270-0166Web: www.dvsinc.com

The proposals in this submission have been formulated by Digital Voice Systems, Inc. (DVSI) to assist the 3GPP2 Standards Committtee. This document is offered to the committee as a basis for discussion and is not binding on DVSI. This submission is subject to change in form and in numerical values after further study, and DVSI specifically reserves the right to add to, or amend, the quantitative statements made herein. Nothing contained herein shall be construed as conferring by implication, estoppel, or otherwise any license or right under any patent, whether or not the use of information herein necessarily employs an invention of any existing or later issued patent.

© Copyright, Digital Voice Systems, Inc. 2000, All Rights Reserved. DVSI hereby gives permission for copying this submission for the legitimate purposes of the 3GPP2 Standards Committee, provided DVSI is credited on all copies. Distribution or reproduction of this document, by any means, electronic, mechanical, or otherwise, in its entirety or any portion thereof, for monetary gain or any non-3GPP2 purpose is expressly prohibited.

GRANT OF LICENSE: DVSI grants a free, irrevocable license to 3GGP2 and its Organizational Partners to incorporate text or other copyrightable material contained in the contribution and any modification thereof in the creation of 3GGP2 publications; to copyright and sell in Organizational Partner’s name any Organizational Partner’s standards publication even though it may include portions of the contribution; and at the Organizational Partner’s sole discretion to permit others to reproduce in whole or in part such contributions or the resulting Organizational Partner’s standards publications. The contributor must also be willing to grant licenses under such contributor copyrights to third parties on reasonable, non-discriminatory terms and conditions as appropriate.

Presented by:

John C. HardwickPresident


3GPP2-DVSI SMV Presentation

26 April 2000Seattle, WA



Presentation Overview

DVSI Introduction

Vocoder Overview

Vocoder Complexity

Vocoder Rate Statistics



DVSI Corporate Information

Specializing in Vocoder development and implementation since 1988

Experience Technical Staff from M.I.T. Chairman - Professor Jae S. Lim President - Dr. John C. Hardwick Director of R&D - Dr. Daniel Griffin

Developer of proprietary model-based (MBE) and hybrid (HX-SD) Vocoders

Focus on vocoder design for wireless applications Developer of the IMBE™ Vocoder which is part of the

ANSI/TIA digital mobile radio standard for APCO Project 25.



DVSI HX-SD™ Selectable Mode Vocoder

Hybrid Excitation - Spectral Decomposition (HX-SD™) Vocoder

Combined harmonic/waveform vocoder Model Parameters: pitch, gain, spectral envelope, and

mixing state for each 20 ms frame of speech Open Loop Analysis, Quantization and Synthesis Variable Frame Size (16, 40, 80 or 170 bits /frame) with

perceptual based rate determination Noise Suppression for improved background noise

performance. Moderate Complexity w/ 40 ms algorithmic delay



HX-SD™ SMV Block Diagram

InputSpeech

OutputSpeech

ParameterAnalysis

ParameterQuantization

WaveformCoding

HarmonicCoding

Bit Stream &Rate Decisions

ParameterDecoding

&Error

Mitigation

WaveformDecoding

HarmonicDecoding

&Synthesis

Encoder Decoder

+Mixingcontrol

Mixingcontrol



HX-SD™ SMV Bit Allocation

- bit allocation for each rate differs for frames which are entirely

waveform encoded from frames which are all or part harmonic

- remaining bits are allocated to waveform and harmonic coders

depending on mixing state

Full-Rate(9.6 kbps)

Half-Rate(4.8 kbps)

Quarter-Rate(2.4 kbps)

Eighth-Rate(1.2 kbps)

Waveform Harmonic Waveform Harmonic Waveform Harmonic Waveform Harmonic

Mixing State 1 4 1 4 1 1 0 xPitch 0 7 0 7 0 3 0 xGain 4 6 4 6 4 4 2 xSpectralMagnitudes

32 32 32 32 32 32 14 x

Remaining 133 121 43 31 3 0 0 x



HX-SD™ SMV Complexity

Rate AlgorithmType

Complexityestimate(MIPs)

Program +Data ROM(kbytes)

StaticRAM(kbytes)

Full-Rate (9.6 kbps) Hybrid 28.5 28 5.2Half-Rate (4.8 kbps) Hybrid 25.7 28 5.2Quarter-Rate (2.4 kbps) Hybrid 16.9 28 5.2Eighth-Rate (1.2 kbps) Hybrid 14.7 28 5.2Combined 28.5 28 5.2

- encoder estimated at 21.2 MIPs, decoder estimated at 7.3 MIPs

- Total ROM is approximately 16.5 kb Data ROM and 11.5 kb Program ROM

- further reductions in MIPS and memory are envisioned



HX-SD™ SMV Rate Statistics

Rate \ Mode Mode 0 Mode 1 Mode2Full-Rate (9.6 kbps) 68% 28% 6%Half-Rate (4.8 kbps) 10% 46% 62%Quarter-Rate (2.4 kbps) 0% (disabled) 4% 10%Eighth-Rate (1.2 kbps) 22% 22% 22%ADR 7.3 kbps 5.3 kbps 4.1 kbps

- Average Data Rate for test vector “vambm22.l22” vs 7.4 kbps for EVRC

- Open Loop Rate Determination based on mode, perceptual difficulty and

Voice Activity Detection (VAD)



Summary

DVSI is a leader in the field of low/medium bit rate vocoders for wireless communications

DVSI has developed a new hybrid vocoder which is being proposed to 3GPP2 for the Selectable Mode Vocoder

DVSI’s hybrid vocoder was designed for high quality speech at low data rates with moderate complexity

dvsi hx-sd™ selectable mode vocoder

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