Hi,
How do i find the start and the end of the envelope from an audio signal ?

 

if variable is like t for time

then type t(1) in command window

and maybe t(end)

might work

or t(length(t))

 

Is it going to work?
Cause basically i'm using hilbert transform to extract the envelope for the speech signal .

 

i don't know. never tried it. but t(1) is initial time
and t(length(t)) is final time

variable could be x or anything so i don't know without seeing the function.

i think its n(1)
n(end) or n(length(n))

just try it and see if it gives you anything.
this is just how many points are taken. but to compute the time i wouldn't know

just look at the side and it has has how long the arrays or vectors are
will say like 1 x 100 which means one row with 100 columns. so 100 elements

fh=[0:Lh-1]/Lh-0.5

therefore x axis is from 0 to length(Hh)-1

so type length(Hh)-1 and returns final value

i don't know

check this site out
https://ccrma.stanford.edu/~jos/sasp/Comparison_use_hilbert_function.html

 

if gives undefined variables..
Do you want me to post up my m-file for you to read up ?

 

yes please. hurry. i'm tired

 

function [data,fs,smoothData] = Uload()

[filename, pathname] = uigetfile('*.wav','Select Data File');



if filename ~= 0

cd(pathname);

% Get data and sampling rate

[data,fs] = wavread([pathname filename]);

% length(data)
% fs
data = data/max(data));
hwin1 = subplot(221);
xlabel('Samples')
ylabel('Signal (Volts)')
ldata = length(data)
tdata = 1:ldata;
cdata = hilbert(data);
[b,a] = butter(5,20/(fs/2),'low');
smoothData = filtfilt(b,a,abs(hilbert(data)));
plot(tdata,2*smoothData,tdata,abs(cdata))
hwin2 = subplot(222);


% [b,a] = butter(5,20/(fs/2),'low');
% smoothData = filtfilt(b,a,abs(hilbert(data)));
% plot(smoothData)
p = fft(data);
ls = length(p);
x=abs(p((1:ceil(ls/2))));
plot(hwin2,x)


% if min(size(data))>1
% error('Can''t load stereo data')
% end

end

%is one of the function to call back for one of my uicontrol to load a wavfile and display the timewaveform (together with the envelope ) , frequency domain (spectrum) as well .

 

so output variables are these [data,fs,smoothData]

this is initial to final data points
tdata = 1:ldata;

so type ldata and will give you final pretty sure

can't even find fs=...... in that mess

 

yes , indeed ..=)

 

so you got it?

and its correct for sure?

cause it might be max(length(b)-1,length(a)-1)

check this out and look at NOTE PORTION IN RECTANGULAR BOX!!!!!!!!!!!!!!!!!!
http://www.mathworks.com/access/helpdesk/help/toolbox/signal/filtfilt.html

but in your program i think that is the max height for first graph

because you have plot(tdata,2*smoothData) so x is bottom and 2*smoothData is top
there fore x axis is 1:ldata and y axis is -2*(max(length(b)-1,length(a)-1)):2*(max(length(b)-1,length(a)-1))

 

http://cnx.org/content/m14198/latest/
Check this website.
This is what i want to achieve ..

 

It looks like 1data gives you the whole length of the data ...

 

read my previous post.

so want to achieve time?

 

http://cnx.org/content/m14198/latest/
Can you please check this website
This is what i want to achieve

 

i did. its same thing your doing except your version has n data points instead of time on bottoms. right?

well attach your wav file if can or upload it to a website and post link, pm, something, email cause i have no idea what your talking about without running the program. never done this before

 

Yeah it is i suppose (sorry i'm pretty bad at MAtlab ) =(

 

i only have like 3 months experience but have done lots of examples. read previous

 

Ok let me extract it and send it to you

 

Can you give me your email ?

 

you send it to me yet? i think i sent you my email like 3 times cause doesn't show up under my sent messages

when is this due. i'm tired. if can't figure it out in next ten minutes i'm probably going to bed.