how to plot 3d spectrogram from data in txt file

Hi guys ,

I have file which time domain of particular output.

clear all;
clc;

data = readmatrix('t.txt');
% Extract time into vector t, and the signal into vector y.
q = data(:, 1);
r = data(:, 2);

y=q.';
A=r.';


ts=(-y(1,2)+y(1,3))
fs=1/ts
t=fs/5


[sSTFT,f,time]=spectrogram(A,fs/5,0,fs/10,fs); 
assoluto=abs(sSTFT);
figure
spectrogram(s,fs/10,0,1e6,fs)

i am getting this error.

Error using welchparse>segment_info (line 253)

The length of the segments cannot be greater than the length of the input signal.

Error in welchparse (line 34)

[L,noverlap,win] = segment_info(M,win1,noverlap1);

Error in pspectrogram (line 34)

[x,nx,~,y,ny,win,~,~,noverlap,~,~,options] = welchparse(x,esttype,varargin{:});

Error in spectrogram (line 170)

[varargout{1:nargout}] = pspectrogram({x},'spect',varargin{:});

Could anyone pls help me out to resolve the issue?

[Walter Roberson]

What are the 'B' in the f.txt file after the positive values, such as

4.31557122927125e+001B

[Walter Roberson]

To deal with the 'B' suffix:

f = readmatrix('f.txt', 'Suffix', 'B');

[Venkatkumar M]

you can negelect 'B' it is unit decibel(dB)

Answer 1

[Mathieu NOE]

hi

using Walter's code above + the attachement , you have all the tools to do this spectrogram analysis

all the best