SW300070-EVAL Datasheet SW300070-EVAL | P1-P2

dsPIC30F Speech Encoding/Decoding Library

Microchip Technology Incorporated

Summary

The dsPIC30F Speech Encoding/Decoding Library performs

toll-quality voice compression and voice decompression. The

library is based on a modified version of Speex source code

and features a 16:1 compression ratio. It samples speech

at 8 kHz and compresses it to a rate of 8 kbps. Storing

compressed speech for playback requires approximately

1 KByte of memory for each second of speech. The library is

especially suitable for the following voice-based applications:

• Answering machines

• Building and home safety systems

• Intercoms

• Smart appliances

• Voice recorders

• Walkie-talkies

• Any application using message playback

Description

The Speech Encoding/Decoding Library is a modified

version of the Speex speech coder made specifically for

the dsPIC30F family of Digital Signal Controllers (DSCs).

Encoding uses Code Excited Linear Prediction (CELP), which

is a popular coding technique. CELP provides a reasonable

trade-off between performance and computational complexity.

The library samples speech at 8 kHz and compresses it to

a rate of 8 kbps. The library is appropriate for half-duplex

systems, such as answering machines, intercoms and walkie-

talkies. With the decoder’s small footprint, the library is also

ideal for playback-only applications, such as building safety

systems and smart appliances.

Predominantly written in assembly language, the Speech

Encoding/Decoding Library optimizes computational

performance and minimizes RAM usage. A well-defined API

makes it easy to integrate with your application.

A flexible analog interface gives your design several

options to consider. The speech encoder samples speech

at 8 kHz using either an external codec or the on-chip

12-bit analog-to-digital converter. The speech decoder

plays decoded speech through an external codec or the

on-chip pulse-width-modulator (PWM).

A PC-based Speech Encoder Utility program (pictured above)

allows you to create your own encoded speech files for

playback. Encoded speech files are made from either a PC

microphone or existing WAV file. Once you create the encoded

speech files, they are added to your MPLAB® C30 project, just

like a regular source file, and built into your application.

The Speech Encoder Utility allows you to select four target

memory areas to store your speech file: program memory,

data EEPROM, RAM and external flash memory. External flash

memory allows you to store many minutes of speech

(1 minute of speech requires 60 KB) and it is supported

through a dsPIC30F general purpose I/O port.

Features

Key features of the Speech Encoding/Decoding Library include:

• Fixed 8 kHz sample rate

• Fixed 8 kbps output rate

• PESQ-based Mean Opinion Score: 3.7 – 4.2 (out of 5.0)

• Code Excited Linear Prediction (CELP)-based coding

• Two analog input interfaces – codec or on-chip 12-bit ADC

• Two analog output interfaces – codec or on-chip PWM

• Optional Voice Activity Detection

• Playback-only applications will benefit from the Speech

Encoder Utility. It allows you to make encoded speech

files from your desktop using a PC microphone or WAV file

• Storing compressed speech requires 1 KB of memory per

second of speech

• Off-chip support for playback of long speech samples

• Royalty free (only one-time license fee)

• Full compliance with Microchip MPLAB® C30 Language

Tools

• dsPIC30F Speech Encoding/Decoding Library User’s

Guide is provided to help the user understand and use

the library (DS70154)

• Designed to run on dsPICDEM™ 1.1 General Purpose

Development Board (DM300014)

Microchip Technology Inc. • 2355 W. Chandler Blvd. • Chandler, AZ 85224-6199 USA • (480) 792-7200 • FAX (480) 792-7277

The Microchip name and logo, the Microchip logo, Accuron, dsPIC, KEELOQ, microID, MPLAB, PIC, PICmicro, PICSTART, PRO MATE, PowerSmart, rfPIC and SmartShunt are registered trademarks of Microchip

Technology Incorporated in the U.S.A. and other countries. AmpLab, FilterLab, Migratable Memory, MXDEV, MXLAB, PICMASTER, SEEVAL, SmartSensor and The Embedded Control Solutions Company

are registered trademarks of Microchip Technology Incorporated in the U.S.A. Analog-for-the-Digital Age, Application Maestro, dsPICDEM, dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR, FanSense,

FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, MPASM, MPLIB, MPLINK, MPSIM, PICkit, PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal, PowerInfo, PowerMate, PowerTool, rfLAB, rfPICDEM,

Select Mode, Smart Serial, SmartTel Total Endurance and WiperLock are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology

DS70146A

*DS70146A*

Part Numbers and Ordering Information

Devices Supported

• dsPIC30F5011 • dsPIC30F6011 • dsPIC30F6013

• dsPIC30F5013 • dsPIC30F6012 • dsPIC30F6014

Resource Requirements

Decoder:

Playback Interface: Si-3000 Audio Codec or PWM

Computational Power: 3 MIPs

Program Flash Memory: 15 KB

RAM*: 3.2 KB

Encoder:

Sampling Interface: Si-3000 Audio Codec or 12-bit ADC

Computational Power: 19 MIPs (worst case)

Program Flash Memory: 33 KB

RAM*: 5.4 KB (1.2 KB is scratch)

Full-duplex support is presently not possible due to RAM requirements,

but support will be provided with future devices. Half-duplex support is

now possible and requires 6.8 KB of RAM.

Host Requirements

• PC-compatible system with an Intel Pentium® class or higher

processor or equivalent

• A minimum of 16 MB RAM

• A minimum of 40 MB available for hard drive space.

• CD-ROM drive

• Microsoft Windows® 98, Windows NT® 4.0 or Windows XP®

dsPIC30F Speech Encoding/Decoding Library

Part Number Description Availability

SW300070-EVAL dsPIC30F Speech Encoder/Decoder Library Software License (Evaluation Only) Q2/2005

SW300070-5K dsPIC30F Speech Encoder/Decoder Library Software License (Up to 5K Units) Q2/2005

SW300070-25K dsPIC30F Speech Encoder/Decoder Library Software License (Up to 25K Units) Q2/2005

SW300070-100K dsPIC30F Speech Encoder/Decoder Library Software License (Up to 100K Units) Q2/2005

Note: Quantities are per project, payable as a one-time license fee based on estimated lifetime volume for products resulting from the project.

Please consult the factory for quantities above 100K.

dsPIC®DSC Development Tools from Microchip

MPLAB

IDE Free

MPLAB

Visual Device Initializer (included in MPLAB

IDE)

MPLAB

C30 C Compiler SW006012

MPLAB

ICD 2 In-Circuit Debugger/Programmer DV164005, DV164007

MPLAB

ICE 4000 ICE4000

MPLAB

PM3 Universal Device Programmer DV007004

dsPIC30F Math Library (included in download of MPLAB

C30 C Compiler) Free

dsPIC30F DSP Library Free

dsPIC30F Peripheral Library Free

dsPICworks™ Data Analysis and DSP Software Free

dsPIC

DSC Digital Filter Design SW300001

dsPIC30F Soft-Modem Library SW300002/3/4/5

dsPIC

DSC Speech Recognition Library SW300010/11/12

dsPIC

DSC Symmetric Key Embedded Encryption Library SW300050

dsPIC

DSC Asymmetric Key Embedded Encryption Library SW300055

dsPIC30F Acoustic Echo Cancellation Library SW300060

dsPIC30F Noise Suppression Library SW300040

CMX-RTX™ for dsPIC30F SW300031

CMX-Tiny+™ for dsPIC30F SW300032

CMX-Scheduler™ for dsPIC

Devices Free at www.cmx.com

dsPICDEM™ Starter Demonstration Board DM300016

dsPICDEM™ 28-pin Starter Demonstration Board DM300017

dsPICDEM™ 1.1 General Purpose Development Board DM300014

dsPICDEM™ MC1 Motor Control Development System DM300020

dsPICDEM.net™ 1 Connectivity Development Boards DM300004-1

dsPICDEM.net™ 2 Connectivity Development Boards DM300004-2

Visit our web site at www.microchip.com for additional product information and your local sales office.

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SW300070-EVAL

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Description:

Development Software Speech Encoding/ Decoding Lib

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SW300070-EVAL