DM300024 Microchip Technology, DM300024 Datasheet - Page 18

• Manufacturer Part Number: DM300024
• Description: KIT DEMO DSPICDEM 1.1
• Manufacturer: Microchip Technology
• Type: MCUr

Specifications of DM300024

• Contents: Board, Cable, CD, Power Supply
• Silicon Manufacturer: Microchip
• Core Architecture: DsPIC
• Core Sub-architecture: DsPIC30F
• Features: Serial Communication Channels Interface, General Purpose Prototyping Area
• Silicon Core Number: DsPIC30F, DsPIC33F
• Silicon Family Name: DsPIC30F6xxx, DsPIC33FJxxGPxxx
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: dsPIC30F/33F and PIC24H
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

Line Echo Cancellation Library
This library provides a function to cancel electrical line echoes
caused by 2- to 4-wire conversion hybrids in telephone lines.
The library can be used in long distance voice communication
applications, especially in links involving satellite networks and
intercontinental long haul networks, as well as digital networks,
such as Voice over IP (VoIP). This library is fully compliant with
the ITU-T G.168 recommendation. The library can be used for
full-duplex operation. It handles 0-4 kHz audio bandwidth (8 kHz
sampling of 16-bit speech data).
Libraries for Speech Applications
Speech Encoding/Decoding Libraries
Three options exist for a variety of speech compression/encoding and decompression/decoding applications:
■
■
Noise Suppression Library
This application library suppresses the
noise interference in a speech signal,
such as ambient noise picked up by
a microphone while capturing speech.
This algorithm is particularly useful for
systems such as hands-free phones,
speakerphones, intercoms and headsets
where an isolated noise reference is not
available. The algorithm handles 0-4 kHz
audio bandwidth and provides 10-20
dB of noise reduction. The library also
includes some sample rate conversion
functions to support input/output
sampling rates of 9.6 kHz, 11.025 kHz
and 12 kHz.
Acoustic Echo Cancellation Library
This library provides a function to eliminate the echo
generated in the acoustic path between a speaker and a
microphone, such as in a speakerphone or an intercom
system. This library is fully compliant with the G.167
standard and provides 16, 32 or 64 ms echo delays.
It handles 0-4 kHz audio bandwidth and provides echo
cancellation of 40-50 dB. It also includes some sample rate
conversion functions to support input/output sampling rates
of 9.6 kHz, 11.025 kHz and 12 kHz.
Speech Recognition
Automatic Speech Recognition (ASR) for the dsPIC DSCs supports
a variety of voice-activated applications like handset and home
appliance control. A Speech Word Library Builder and a Speech
Recognition Software Library make up the ASR software suite.
18
G.711
G.726A
Speex
Vocoder
G.726A is an implementation of the ITU-T G.726 Annex A standard which uses Adaptive Differential Pulse Code Modulation
(ADPCM) encoding algorithm. It can achieve up to an 8:1 compression ratio depending on output bit rate selected.
Speex is a popular standard in the LINUX workstation community which has been adapted for the dsPIC DSC. It uses Code
Excited Linear Prediction (CELP) encoding pioneered for cellular applications. It can achieve a 16:1 compression ratio.
■
G.711 is available for free. The library is an implementation of the ITU-T G.711 standard which uses A-law or μ-law
companding to achieve 2: 1 compression.
Data Rate (16-bit)
16-bit Embedded Control Solutions
Incoming
8/16 kHz
8 kHz
8 kHz
16 to 40 kbps
64 kbps
Output
8 kbps
Rate
Speech Quality
4.3-4.5
4.3-4.5
3.7-4.2
(MOS)
Near End
Speech
MIPS
Far End
Speech
15
19
1
FAR END
Speech Recognition Library Features:
• Speaker independent recognition
• PC-based word library builder
• Up to 100 word vocabulary (American English)
• Supports multiple noise profiles
• Suitable for many voice control applications
Flash
(KB)
33
3
6
Line Cancellation Library Features:
• 8 kHz sampling rate
• Full duplex
• Compliant with ITU-T G.168
• Royalty-free, one-time license
User Application
Acoustic Echo
Cancellation
recommendations
Receive Path
Send Path
Adaptive
Filter
RAM
(KB)
3.6
5.4
4
-
+
PIC24/dsPIC DSC
NEAR END
dsPIC DSC
dsPIC DSC
Near End
Speech
Target
Far End
Speech
ECHO