SW300040-EVAL Microchip Technology, SW300040-EVAL Datasheet

SW300040-EVAL

Manufacturer Part Number

SW300040-EVAL

Description

LIBRARY NOISE SUPPR-EVAL ONLY

Manufacturer

Microchip Technology

Type

Noise Suppression Libraryr

Datasheet

1.SW300040-EVAL.pdf (2 pages)

Specifications of SW300040-EVAL

Tool Function

Library

Tool Type

Library

Processor Series

dsPIC

Core Architecture

dsPIC

Lead Free Status / RoHS Status

Not applicable / Not applicable

For Use With/related Products

dsPIC30F

Lead Free Status / Rohs Status

Lead free / RoHS Compliant

Current page: 1 of 2
Download datasheet (57Kb)

dsPIC30F Noise Suppression Library

Summary

The dsPIC30F Noise Suppression (NS) Library provides a function to

suppress the effect of noise interfering with a speech signal. This

function is useful for microphone-based applications, which have a

potential for incoming speech getting corrupted by ambient noise

captured by the microphone. It is especially suitable for systems in

which an acoustically isolated noise reference is not available,

such as:

•

Description

The Noise Suppression Library is written entirely in assembly language

and is highly optimized to make extensive use of the dsPIC30F DSP

instruction set and advanced addressing modes. The algorithm avoids

data overflow. The Noise Suppression Library provides a

“NoiseSuppressionInit” function for initializing the various data

structures required by the algorithm and a “NoiseSuppression”

function to remove noise from a 10 ms block of sampled 16-bit

speech data. The user can easily call both functions through a

well-documented Application Programmer's Interface (API).

The “NoiseSuppression” function is primarily a Frequency Domain

algorithm. A Fast Fourier Transform (FFT) is performed on each 10 ms

block of data to analyze the frequency components of the signal.

Thereafter, a Voice Activity Detection (VAD) algorithm is used to

determine if the signal segment is speech or noise. The NS algorithm

maintains a profile of the noise and updates it every time a noise

segment is detected by the VAD. Every frequency band of the input

signal is then scaled according to the proportion of noise contained in

that frequency band, thereby causing a significant degree of noise

suppression in the resultant signal. The algorithm, thus, adapts to

changes in the nature and level of noise, and does not require a

separate noise reference input.

The dsPIC30F Noise Suppression Library uses an 8 kHz sampling

rate. However, the library includes a sample rate conversion

function that ensures interoperability with libraries designed for

higher sampling rates (9.6 kHz, 11.025 kHz or 12 kHz). The

conversion function allows incoming signals at higher sampling

rates to be converted to a representative 8 kHz sample. Similarly,

the conversion function allows the output signal to be converted

upward from 8 kHz to match the user application.

Hands-free Cell Phone Kits

Speakerphones

Intercoms

Teleconferencing Systems

Headsets

As a front-end to a Speech Recognition system

Any microphone-based application that needs to eliminate

undesired noise

and Speech

Noise

M i c r o c h i p T e c h n o l o g y I n c o r p o r a t e d

User Application

Suppression

Noise

Features

Key feature of the Noise Suppression Library include:

•

Resource Requirements

Noise Suppression

Computational Requirements: 3.3 MIPS

Program Flash Memory: 7 KB

RAM: 1 KB

Sample Rate Conversion

Computational Requirements: 1 MIPS

Program Flash Memory: 2.6 KB

RAM: 0.5 KB

Note: The user application might require an additional 1 KB-1.5 KB

Devices Supported

dsPIC30F6014

dsPIC30F6012

dsPIC30F5013

dsPIC30F5011

dsPIC30F4013

All functions can be called from either a C or assembly

application program

Five user functions:

–

Full compliance with the Microchip dsPIC30F C30 C Compiler,

Assembler and Linker

Simple user interface – just one library file and one header file

Highly optimized assembly code, utilizing DSP instructions and

advanced addressing modes

Audio Bandwidth: 0-4 kHz at 8 kHz sampling rate

10-20 dB noise reduction, depending on type of noise

–

“dsPIC30F Noise Suppression Library User's Guide” is provided

to help the user understand and use the library

Demo application source code is provided with the library

Accessory Kit available for purchase includes: an audio cable,

headset, oscillators, microphone, speaker, DB9 M/F RS-232

cable, DB9M-DB9M Null Modem Adapter and can be used for

library evaluation

NoiseSuppressionInit

NoiseSuppression

InitRateConverter

SRC_upConvert

SRC_downConvert

Several speech recordings corrupted by Babble, Car Cabin,

White and Narrowband Noise included for library evaluation

of RAM for data buffering (application-dependent).

Speech

Related parts for SW300040-EVAL

SW300040-EVAL Summary of contents

Page 1

Noise Suppression Library Summary The dsPIC30F Noise Suppression (NS) Library provides a function to suppress the effect of noise interfering with a speech signal. This function is useful for microphone-based applications, which have a potential for incoming speech getting ...

Page 2

... Windows ® 98, Windows 2000 or Windows XP Part Numbers and Ordering Information: Part Number SW300040-EVAL dsPIC30F Noise Suppression Library Software License (Evaluation Only) SW300040-5K dsPIC30F Noise Suppression Library Software License ( units) SW300040-25K dsPIC30F Noise Suppression Library Software License (5K+ to 25K units) SW300040-100K ...

Related keywords

sw3000
sw300
SW300040-EVAL datasheet
SW300040-EVAL data sheet
SW300040-EVAL pdf datasheet
SW300040-EVAL component
SW300040-EVAL part
SW300040-EVAL distributor
SW300040-EVAL RoHS
SW300040-EVAL datasheet download