Spectrogram example in Matlab

Question

Is there Matlab code that shows a series of numbers representing a waveform as a spectrogram?

The time interval each sample represents is the same, idearly this could also be given to use for the axis scale.

For example:

spec({1 2 3 2 1 2 3 2}, 0.1 seconds)

or

spec(my_data.txt, 10 Hz)

etc...

Yes, there's an example here: mathworks.co.uk/help/toolbox/signal/ref/spectrogram.html. — Oliver Charlesworth
– Oliver Charlesworth, Commented Mar 15, 2012 at 19:22

Oliver Charlesworth · Accepted Answer · 2012-03-15 20:52:58Z

4

If you have the Signal Processing Toolbox, then you can use the spectrogram() function. e.g.:

T = 0:0.001:2;
X = chirp(T,100,1,200,'q');
spectrogram(X,128,120,128,1E3);

(Example taken from that documentation page.)

The numeric params are window length, overlap length, FFT length and sampling frequency, respectively.

answered Mar 15, 2012 at 20:52

Oliver Charlesworth

274k34 gold badges590 silver badges687 bronze badges

Sign up to request clarification or add additional context in comments.

4 Comments

alan2here Over a year ago

And for external data it's X = cell2mat({1 2 3 etc...}) or paste into the Workspace window.

Oliver Charlesworth Over a year ago

@alan2here: What is "external data"? cell2mat seems excessive; just use square brackets if you want a normal array.

alan2here Over a year ago

External data, you know, data that comes from somewhere else. Like a list of numbers I've downloaded from the internet instead of generating in Matlab. Also cell2mat works, using square brackets instead generates "X must be a vector (either row or column)." because X ends up being the wrong type for spectrogram.

Oliver Charlesworth Over a year ago

@alan2here: X = [1 2 3 4 5 6]; spectrogram(X,...); should work fine. In general, you should cell arrays (i.e. arrays declared using {}) unless you really need them, because they screw up all sorts of things.

bandybabboon · Accepted Answer · 2015-07-13 04:29:56Z

0

if you look on tftb toolbox, the tfrspwv is a very complex and precise spectrogram code and there is an running script example in the tfrspwv.m code online for making a spectrogram in Matlab.

answered Jul 13, 2015 at 4:29

bandybabboon

2,3861 gold badge25 silver badges39 bronze badges

Collectives™ on Stack Overflow

Spectrogram example in Matlab

2 Answers 2

4 Comments

Comments

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

4 Comments

Comments

Related