Project Title
Echo
Cancellation Of an audio
Signal
FIR
Filter Design Using Windowing
Method
Submitted To
 Mr. S.M. Haider Ali Shuvo
 Lecturer UIU

Group 10
Group Members
Md . Abdul Ahad
021201107
Md Sohiduzzaman Rimon
021193010
TOPICS
• Introduction
• Types Of Echo
• Causes Of Echo
• The Process Of Echo Cancellation
• Matlab Code
•Matlab Wave
• Conclusion
Introduction

An echo is the reflection of sound that arrives at the
listener's ear after bouncing off a surface. It's created
when sound waves bounce off a solid object and return to
the listener, producing a repetition of the original sound,
usually with a delay. Echoes occur in environments with
hard surfaces that reflect sound, like mountains,
buildings, or large open spaces.
ECHO TYPES

There are a few types of echoes:
1. Acoustic Echo: This is the reflection of sound off hard
surfaces, like walls or mountains, creating a delayed repetition
of the original sound.
2. Line Echo: Commonly found in telecommunications, it's a
delayed repetition of a transmitted signal caused by signal
reflections or delays in the communication line.
3. Digital Echo: In audio technology, this is an effect applied
intentionally to create a repeated, fading echo, often used in
music or sound effects.
 Each type of echo arises from different sources and is
manipulated or utilized in various ways across technology,
communication, and sound manipulation.
Causes Of Echo
The primary causes include:

• Acoustic echo apart, background noise is generated
through the network when analog and digital are
operated in hand free mode .

• Digital Processing Delay and speech compression
techniques further contribute to echo generation and
degraded voice quality in wireless network. •

one-way Delay is Greater than 16ms
THE PROCESS OF ECHO
CANCELLATION

Echo cancellation is a method used to eliminate or
reduce unwanted echoes in communication systems.
Here's a simplified process:
Capture: The system first captures the incoming audio,
which includes both the original signal and the echo.
Analysis: It analyzes the incoming audio to identify the
components that constitute the echo.
Generation of Anti-echo Signal: Using adaptive
algorithms, the system generates a replica of the echo,
known as the anti-echo or cancellation signal.
Adaptation: The cancellation process is often adaptive,
continuously adjusting to changes in the echo characteristics
due to varying conditions like network delays or environmental
changes.
Output: The result is a processed audio output that ideally
contains minimal or no echo, improving the clarity of
communication.

This process happens rapidly and continuously during live
communication, facilitating clearer conversations without
distracting echoes
Matlab Code

clc

clear all

close all

%Reading the original audio signal

fs=44100;

original=audioread('Mi.mp3');

%Playing the original song

p=audioplayer(original,fs);

play(p)

figure

plot(original)

grid on

title('Original Signal','Fontsize',16)

Adding Echo

%Adding echo

zeros=[1,zeros(1,4800),0.8];

poles=[1];

echo_signal=filter(zeros,poles,original);

p=audioplayer(echo_signal,fs);

play(p);

figure

plot(echo_signal)

grid on

title('Echo Signal','Fontsize',16)
Removing Echo

%Removing echo

poles=[1,zeros(1,4800),0.8];

zeros=[1];

removing_audio=filter(zeros,poles,echo_signal);

p=audioplayer(removing_audio,fs);

play(p);

stop(p)

figure

plot(echo_signal)

grid on

title('After Remove Echo','Fontsize',16)
Matlab Wave
Matlab Wave
Matlab Wave
Conclusion

The echo cancellation project demonstrates remarkable
effectiveness in eliminating echoes, ensuring crystal-clear audio
quality while efficiently enhancing the overall communication
experience.

By successfully suppressing echoes, the project significantly
elevates user experience, fostering seamless and more natural
conversations across various platforms, ultimately leading to
greater satisfaction among users.
THANK YOU
for giving your time
for me