plotting pre-emphasis

SAF
2019 12 25
2 个回答
更新时间：2019 12 25
5 次查看（30 天）

0 个投票

Hello,
I am trying to plot the signal before and after the pre emphasis filter but I'm getting error "Dot indexing is not supported for variables of this type."
Any suggestions?
The full code:
waveFile='whatFood.wav';
au=myAudioRead(waveFile); y=au.signal; fs=au.fs
a=0.95;
y2 = filter([1, -a], 1, y);
time=(1:length(y))/fs;
au2=au; au2.signal=y2;
myAudioWrite(au2, 'whatFood_preEmphasis.wav');
subplot(2,1,1);
plot(time, y);
title('Original wave: s(n)');
subplot(2,1,2);
plot(time, y2);
title(sprintf('After pre-emphasis: s_2(n)=s(n)-a*s(n-1), a=%f', a));
subplot(2,1,1);
set(gca, 'unit', 'pixel');
axisPos=get(gca, 'position');
uicontrol('string', 'Play', 'position', [axisPos(1:2), 60, 20], 'callback', 'sound(y, fs)');
subplot(2,1,2);
set(gca, 'unit', 'pixel');
axisPos=get(gca, 'position');
uicontrol('string', 'Play', 'position', [axisPos(1:2), 60, 20], 'callback', 'sound(y2, fs)');

请先登录，再回答此问题。

回答（2 个）

Image Analyst
Image Analyst 2019-12-25

0 个投票

Why are you using those functions instead of the built-in ones? The code below works using the built-in functions:
waveFile='guitartune.wav';
[y, fs] = audioread(waveFile);
% [y, fs] = myAudioRead(waveFile);
% y=au.signal;
% fs=au.fs
a=0.95;
y2 = filter([1, -a], 1, y);
time=(1:length(y))/fs;
% au2=au;
% au2.signal=y2;
% myAudioWrite(au2, 'whatFood_preEmphasis.wav');
audiowrite('whatFood_preEmphasis.wav', y2, fs);
soundsc(y, fs);
subplot(2,1,1);
plot(time, y);
grid on;
title('Original wave: s(n)');
subplot(2,1,2);
plot(time, y2);
title(sprintf('After pre-emphasis: s_2(n)=s(n)-a*s(n-1), a=%f', a));
subplot(2,1,1);
set(gca, 'unit', 'pixel');
axisPos=get(gca, 'position');
uicontrol('string', 'Play', 'position', [axisPos(1:2), 60, 20], 'callback', 'sound(y, fs)');
subplot(2,1,2);
set(gca, 'unit', 'pixel');
axisPos=get(gca, 'position');
uicontrol('string', 'Play', 'position', [axisPos(1:2), 60, 20], 'callback', 'sound(y2, fs)');
grid on;
0000 Screenshot.png

3 个评论
显示 1更早的评论 隐藏 1更早的评论

SAF
SAF 2019-12-25
Thnak you so much for you help, i could not find the code for the built in one. tbh im not sure how to find it. im also looking for a function to apply hamming window on wav file and plot the outout, any idea how?
Image Analyst
Image Analyst 2019-12-25
You could try to edit it
>> edit audioread.m
though I don't know why you need the source code for those built-in functions.
I'm not exactly sure if you want a sliding hamming window or one that covers the whole waveform. Please give the formula (so I don't have to look it up).
SAF
SAF 2019-12-25
im looking for the one that covers the whole waveform, sorry i cant find it because its my first time using matlab.
also the code above worked thank you. may i ask how do i find built in codes to use in the future?

请先登录，再进行评论。

Star Strider
Star Strider 2019-12-25

0 个投票

I looked at your filter, and note that it is not actually doing any filtering. The output is essentially the same as the input, although with a 0.4455 dB attenuation.
To design a FIR filter that automatically uses a Hamming wndow, use the fir1 function.
You can also use the designfilt function.

类别

在 帮助中心 和 File Exchange 中查找有关 Simulation, Tuning, and Visualization 的更多信息

标签

提问:

SAF
SAF
2019-12-25

回答：

Star Strider
Star Strider
2019-12-25

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by