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, k ee l oq , 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, seeva l, 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, d spicdem, 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 incorporated in the u.s.a. all other trademarks mentioned herein are property of their respective companies. ? 2005, microchip technology incorporated, printed in the u.s.a., all rights reserved. 4/05 ds70 146a *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 t he 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 dv 164005, 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 s w300050 dspic ? dsc asymmetric key embedded encryption library s w300055 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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