Interference Removal of Speech Signal

ABSTRACT

Unwanted frequency generates noise in environment. Noise is annoying. Louder the noise, greater the annoyance. The noise cancellation is severe problem in signals. It is estimated from the equation

x(n)=d(n)+v1(n)

A filter is a device when a signal is given; it changes to some desired form by changing its shape, amplitude, frequency or phase frequency. They are usually employed to remove the noise, extract information signals and separate two or more combined signals. There are two main classes of filter, analog and digital filter.

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Notch Filter 1:

Type of Notch filter: Chebyshev filter

Center frequency: 360 Hz

Bandwidth: 60 Hz.

Pass band ripple: 0.5 dB

Stop band attenuation: 5 dB at 355 Hz and 365 Hz respectively

Notch Filter 2:

Type of Notch filter: Chebyshev filter

Center frequency: 1080 Hz

Bandwidth: 60 Hz.

Pass band ripple: 0.5 dB

Stop band attenuation: 5 dB at 355 Hz and 365 Hz respectively

CHAPTER 1

INTRODUCTION

This project of signal processing is simulated using MATLAB software which basically helps in the exact mapping of the signal with the help of an figure window. MATLAB (matrix laboratory) is a multi-paradigm numerical computing environment and fourth-generation programming language. Developed by Math Works, MATLAB allows matrix manipulations, plotting of functions and data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other languages, including C, C++, Java, Fortran and Python.

Although MATLAB is intended primarily for numerical computing, an optional toolbox uses the MuPAD symbolic engine, allowing access to symbolic computing capabilities. An additional package, Simulink, adds graphical multi-domain simulation and Model-Based Design for dynamic and embedded systems.

MATLAB has structure data types. Since all variables in MATLAB are arrays, a more adequate name is "structure array", where each element of the array has the same field names. In addition, MATLAB supports dynamic field names (field look-ups by name, field manipulations, etc.). Unfortunately, MATLAB JIT does not support MATLAB structures; therefore just a simple bundling of various variables into a structure will come at a cost. In other words MATLAB is also called as graphic or graphical interface programming.

MATLAB supports developing applications with graphical user interface features. MATLAB includes GUI (GUI development environment) for graphically designing GUIs .It also has tightly integrated graph-plotting features. For example the function plot can be used to produce a graph from two vectors x and y. The code below produces the following figure of the sine function:

x = 0:pi/100:2*pi;

y = sin(x);

plot(x,y)