Generated script from Signal Analyser app - How to plot spectrogram?

Hi!

I managed to import signal and set settings in Signal Analyser app. I generated script and want to add it to the rest of the code.

Below is the generated script:

% Compute spectrogram

% Generated by MATLAB(R) 9.8 and Signal Processing Toolbox 8.4.
% Generated on: 21-Jan-2021 22:40:31

% Parameters
timeLimits = [0 1.470999]; % seconds
frequencyLimits = [0 120000]; % Hz
timeResolution = 1; % seconds
overlapPercent = 50;

%%
% Index into signal time region of interest
konst_svetlobni_tok_ROI = konst_svetlobni_tok(:);
sampleRate = 1000000; % Hz
startTime = 0; % seconds
timeValues = startTime + (0:length(konst_svetlobni_tok_ROI)-1).'/sampleRate;
minIdx = timeValues >= timeLimits(1);
maxIdx = timeValues <= timeLimits(2);
konst_svetlobni_tok_ROI = konst_svetlobni_tok_ROI(minIdx&maxIdx);
timeValues = timeValues(minIdx&maxIdx);

% Compute spectral estimate
% Run the function call below without output arguments to plot the results
[P,F,T] = pspectrum(konst_svetlobni_tok_ROI,timeValues, ...
    'spectrogram', ...
    'FrequencyLimits',frequencyLimits, ...
    'TimeResolution',timeResolution, ...
    'OverlapPercent',overlapPercent);

If I am right, this script does not include command to plot spectrogram.

How can I plot it? What do I have to add to script?

Best regards!

Answer 1

[Cris LaPierre]

Look at the comment just above the call to pspectrum. With output arguments assigned, it does not create a spectrogram. However, if you remove the output arguments, it will create the indicated plot (spectrogram here).

pspectrum(konst_svetlobni_tok_ROI,timeValues, ...
    'spectrogram', ...
    'FrequencyLimits',frequencyLimits, ...
    'TimeResolution',timeResolution, ...
    'OverlapPercent',overlapPercent);

[Matic Markovic]

Thank you!

I did not know what exactly was meant with "output arguments".

Is it possible to swap x-axis and y-axis?

[Cris LaPierre]

It is possible with the spectrogram function (specify 'yaxis' as the freqloc). I don't see a similar setting for pspectrum.

[Matic Markovic]

Thank you!