代写ECE 425/525、代做Digital Signal Processing、Matlab编程调试、Matlab代写

日期：2019-05-11 11:19

ECE 425/525 Digital Signal Processing

Spring 2019

Dept. of Electrical and Computer Engineering Miami University

1

Homework 11 Assignment

Weights: 60pts

Due Date: May 10, 2019.

Turn in Method: Turn in your report with your Matlab? program and other supporting materials

listed at the end of this handout via Canvas by the midnight of May 10, 2019.

Project Description:

In this project, you will use two bandstop IIR filters to filter out noise.

Conduct the following task.

1. Download the test wave file, ‘test3.wav’, from the Canvas.

2. Use Matlab audioread command (or other Matlab command) to find out the sampling

frequency of the wave file and save the voice to x[k].

3. Play x[k] with Matlab?.

4. Get the magnitude and phase spectra of x[k] with fft command and plot them. Since the

length of x[k] can be too long, you might want to specify the size of FFT output. Refer to

Matlab help menu on how to specify the length of FFT result. (Note: x-axis unit needs to

be Hz and y-axis unit needs to be dB (magnitude spectrum) or radian (phase spectrum))

a. Since fft(x) will generate a complex valued array, you need to use Matlab

commands ‘abs’ and ‘angle’ to get magnitude and phase spectrum of your

signal.

b. You only need to plot the first-half of you FFT result. Why?

5. The signal (x[k]) is corrupted by two narrowband interferences. Based on the magnitude

spectrum you obtain in step 4, design two bandstop digital IIR filters so you can use them

sequentially to remove these interferences.

6. Plot the frequency response spectra of the bandstop filters with freqz command (x-axis

unit: Hz)

7. Apply your two bandstop filters in sequence to filter the x[k] and save your result into y[k].

8. Play y[k].

9. Get the magnitude and phase spectra of y[k] with fft command and plot them. (Note: xaxis

unit needs to be Hz and y-axis unit needs to be dB (magnitude spectrum) or radian

(phase spectrum))

10. Save y[k] into a wav format file.

Submission Request

You need to turn in the followings:

(1) Matlab? codes

(2) The filtered voice in wav format

(3) The frequency response spectra of two bandstop filters

ECE 425/525 Digital Signal Processing

Spring 2019

Dept. of Electrical and Computer Engineering Miami University

2

(4) The magnitude and phase spectra of x[k] and y[k].

Matlab? Commands You Might Need

audioplayer, play, wavread, sound, xcorr, zeros, ones, fft, ifft, abs, angle, unwrap, real,

imag, freqz, freqzplot, filter, subplot, buttord, cheb1ord, cheb2ord, ellipord, butter, cheby1,

cheby2, ellip, lp2bp, bilinear.

Note: These commands are provided for you convenience, you should not assume that they are

the only commands you need for this assignment.

Example Matlab Program for filter design (Read Matlab help for ellipord and ellip)

Fs=8000;

Wp1=[300 3000];

Ws1=[500 2000];

[N, Wp] = ellipord(Wp1/(Fs/2), Ws1/(Fs/2), 0.5, 40)

[B1,A1] = ellip(N,0.5, 40,Wp,'stop');

freqz(B1,A1,1024,Fs);