OROS-CD16
Speech Coders/Decoders
by OROS

Software Overview

OROS is offering TMS320C2x digital signal processing software modules for real-time coding.
The following set of speech coders/decoders for various bit rates is available:
•	LPC 10 at 2,400 bps
•	LPC Multipulse at 4.8 kbps
•	LPC Multipulse at 8 kbps·
•	PC Multipulse at 9.6 kbps
•	LPC Multipulse at 16 kbps
•	MIC G.721 at 32 kbps
•	MIC G.722 at 64 kbps
These algorithms are meant to be used directly on the OROS-AU21 PC board, or to be implemented on 
specific hardware.
The source code of the algorithms can be supplied under license and ported onto other fixed-point 
DSPs (`C2x, `C5x).
OROS offers the relative technical support: training, customization, implementation.
The target applications for these software are:
•	Speech storage: Answering machines, store-and-forward servers, public address, vocal guide
•	Speech transmission on low-bit-rate channels
An evaluation package, OROS-CD16, is available to run these coders/decoders directly on a PC board.

Features and Benefits

All these algorithms were developed by OROS in assembly language, optimized for the TMS320C2x.
Analog environment: ΅ or A-law codec, or 16-bit linear converter. Half-duplex or full-duplex 
implementation.	
Available coders:
•	2.4 kbps  LPC10
•	4.8 kbps  MPLPC: LPC10, 222 pulses/sec
•	8 kbps    MPLPC: LPC12, LTPP, 677 pulses/sec
•	9.6 kbps  MPLPC: LPC14, LTPP, Huffman coding, 900 pulses/sec
•	16 kbps   MPLPC: LPC14, LTPP, 1,333 pulses/sec
•	32 kbps   MIC G.721
•	64 kbps   MIC G.722

Processor and System Requirements

•	All these algorithms run on the TMS320C25 and can be easily ported to the `C5x family. The 
requirements are different for each coder/decoder.
•	For instance: 8 kbps
Program memory: 4 kwords
RAM: 2 kwords external 80% of CPU capacity (`C25/40 MHz).

Algorithm Verification

•	These coders/decoders are primarily suited for non-normalized applications.
•	The performances are evalued in technical terms: quality speech, delay, memory and calculation 
capacity required, robustness.
•	The OROS-CD16 evaluation kit allows you to run all of them, evaluate, and compare coding quality 
and robustness.

Availability

•	Full source code license:
This option includes OROS-CD16 evaluation kit, source code of the selected coder/decoder, training, 
and technical support
•	Run-time license:
This option includes object code for a specified processor to be linked with the application, with 
royalties arrangement.
•	Evaluation kit (OROS-CD16):
This kit comprises a set of all these coders/decoders, an OROS-AU21 board (TMS320C25 and 16-bit 
analog interface), a microphone and loudspeaker, and applications software.
In addition, OROS can adapt these coding algorithms according to specific requirements.

Company Background and Contact Information

OROS has been a specialist in signal processing and speech processing since 1985.
We are active in the real-time signal processing in the audio band. Our main works are in speech 
compression and synthesis, telecom (DTMF, modem, tone detection), and metrology (acoustics, 
vibrations, seismics).
We propose:
•	Standard products: DSP boards (TMS320C25 and TMS320C31 PC boards) and software development tools 
(compilers, libraries of algorithms), customizable FFT analyzers for real-time industrial 
applications.
•	Dedicated products: Developed according to custom requirements: feasability, hardware and 
software design, manufacturing.
•	Research: Involvement in several European Esprit research projects, theoretical works, and 
real-time implementation of algorithms.

Contact:	Franηois Orange
		OROS
		13 chemin des Prιs
		Zirst 4403	
		38241 Meylan
		France
		+33.76.90.62.36.