Hi Nirwana,
Based on my understanding, you want to combine the spectrogram results of multiple signal files into a single, continuous spectrogram plot by comprehensively looping through the spectrogram for individual files.
You can refer to the following steps along with the attached code snippets :
1. Initialize two empty arrays “combined_S” and “combined_T”, to store the concatenated spectrogram data and time indices from all files.
% Initialize empty arrays for concatenated results
combined_S = [];
combined_T = [];
2. Loop through the files and calculate the spectrogram of the current file. Then concatenate the power spectral density to “combined_S” and time indices to “combined_T”.
% Calculate the spectrogram
[Si, Fi, Ti, Pi] = spectrogram(y, wspec, Noverlap, Nspec, fs, 'xaxis');
% Concatenate the results
combined_S = [combined_S, Pi];
if isempty(combined_T)
combined_T = Ti;
else
combined_T = [combined_T, Ti + combined_T(end)];
end
3. Then plot the combined spectrogram using “imagesc” function and further update the plot in each iteration of the loop to visualise the spectrogram built up gradually.
% Update the plot
imagesc(combined_T / 60, Fi, 10 * log10(combined_S));
axis xy;
drawnow;
See the output below for better understanding :
For more details on the “spectrogram” and “imagesc” function, kindly refer to the following documentations:
- https://www.mathworks.com/help/signal/ref/spectrogram.html
- https://www.mathworks.com/help/matlab/ref/imagesc.html
Happy Coding!
