Product category:
Embedded Software and Operating Systems
News Release from: Microchip Technology | Subject: DsPIC30F Speech Encoding/Decoding Library
Edited by the Electronicstalk Editorial
Team on 02 June 2005
Library turns digital signal controllers
to speech
Microchip Technology has released a speech encoding (compression) and decoding (decompression) library for its 16bit dsPIC digital signal controllers.
Microchip Technology has released a speech encoding (compression) and decoding (decompression) library for its 16bit dsPIC digital signal controllers (DSCs) The dsPIC30F Speech Encoding/Decoding Library is based on the Speex open source compression format, and achieves a 16:1 compression ratio and toll quality speech (PESQ 3.7-4.2)
This article was originally published on Electronicstalk on 10 Apr 2001 at 8.00am (UK)
Related stories
World's first serial EEPROM supporting ACR SIG
Microchip has announced the world's first serial EEPROM supporting the Advanced Communications Riser Special Interest Group (ACR SIG) specification.
Easy interfacing to faster microcontrollers
Microchip has added two new devices to its PIC16C92X family of 8bit one-time-programmable microcontrollers with integrated liquid-crystal display controller.
The dsPIC30F Speech Encoding/Decoding Library enables embedded designers to transmit more messages over a given bandwidth, or store longer amounts of speech in a given memory space, while maintaining excellent sound quality and intelligibility.
Many design engineers are seeking to add speech compression to their bandwidth- or memory-constrained applications, but have opted for lower compression methodologies to avoid a stiff per-unit royalty for the intellectual property.
The dsPIC30F Speech Encoding/Decoding Library offers a significant cost reduction over competitive options, and brings non-royalty-bearing 8Kbit/s encoding to the embedded world.
Further reading
BiCMOS op amps feature low offset voltage
Microchip has announced a new family of unity gain stable op amps with low offset voltage.
Flash microcontrollers run up to 10MIPS
Microchip's new PIC18F010 and PIC18F020 Flash microcontrollers offer an industry-leading performance of 10MIPS, 4Kbyte of program memory, 256byte of user RAM and 64byte of EEPROM.
Micropower op amp shrinks into SOT-23 package
Microchip's new 2.5 V micropower operational amplifier is available in a tiny SOT-23 package.
"By adapting the open-source Speex audio compression format, we are providing dsPIC DSC users with low-cost, high-quality compression capability from the open source free software community", said Sumit Mitra, Vice President of Microchip's Digital Signal Controller Division.
"Our customers are very cost conscious and will appreciate the ability to add or improve speech compression with a nonroyalty bearing pricing structure".
Any embedded application that transmits voice over limited bandwidth or has memory constrained playback can benefit from this speech compression/decompression library.
Specific example applications include: voice over IP, tapeless answering machines, voice announcement systems, medical equipment, appliances, building and home safety systems, intercoms, and proprietary communications equipment.
The library has a well-documented application programming interface (API) that makes it easy to incorporate speech compression and/or decompression into an application.
The library also supports optional voice activity detection.
The speech encoder samples data at 8kHz, using either the dsPIC DSC's on-chip 12bit analogue-to-digital convertor or a 16bit input obtained from an external codec, via the on-chip codec interface port.
The encoder achieves up to a 16:1 compression ratio and generates a fixed 8Kbit/s output rate.
Output of decoded speech can be accomplished using the dsPIC DSC's standard PWM or via the interface to an external codec.
The encoder requires 19MIPS (worst case), 33Kbyte of program memory and 6.2Kbyte of RAM.
The decoder requires 3MIPS, 15Kbyte of program memory, and 3.2Kbyte of RAM.
Storing speech requires 1Kbyte of memory for each second of speech.
The library permits the compressed speech data to be stored in on-chip memory (Flash, EEPROM or RAM) or to an external Flash memory.
Playback-only applications can benefit from a PC-based speech encoder utility that is included on the library CD.
This utility creates encoded speech files from a PC microphone or WAV files.
The dsPICDEM 1.1 general purpose development board (DM300014) can be used to evaluate this library.
The following dsPIC DSCs have the on-chip resources needed for this library: dsPIC30F5011, dsPIC30F5013, dsPIC30F6011, dsPIC30F6012, dsPIC30F6013 and dsPIC30F6014.
All licensing options for the dsPIC30F Speech Encoding/Decoding Library are immediately available.
Among these options is a one-year evaluation/development licence, which is unaltered from the library that is used for production and can be purchased from the Microchip website.
The evaluation/development version of the dsPIC30F Speech Encoding/Decoding Library (SW300070-EVAL) is US $5.
Industry-unique, one-time-fee licensing options are also available for production, which runs counter to the per-unit royalty business model that is common for this class of library.
Starting at US $2500 for 5000-unit production, the licence fee that Microchip charges is attractive to many customers is it is a fraction of the cost they would incur developing it themselves.
These one-time fees are based on the estimated lifetime volume of products derived from the product development effort that uses the library.
• Microchip Technology: contact details and other news
• Email this article to a colleague
• Register for the free Electronicstalk email newsletter
• Electronicstalk Home Page
Search the Pro-Talk network of sites
