How can I plot time vs. frequency curve of time-series data?

I want to plot time vs. frequency curve of time-series data. Can anybody help me?

N.B. Please see the attachment

[Orion]

there is no attachment.

[Partha]

Sorry Orion, now see the attachment please.

[Partha]

Is there is any difference between the following codes?

NS = Noisy Signal; windowsize = 128; window = hanning(windowsize); nfft = windowsize; noverlap = windowsize-1; [S_NS F_NS T_NS P_NS] = spectrogram(NS,window,noverlap,nfft,Fs,'yaxis'); AMP_NS = 10*log10(abs(S_NS)); imagesc(T_NS*1e3,F_NS*1e-6,AMP_NS)

and

spectrogram(NS,window,noverlap,nfft,Fs,'yaxis');

Answer 1

[Orion]

Ok, I will not read this full paper.

But I guess you want to make figures like the number 5.

You need to use spectrogram

[Youssef Khmou]

spectrogram is the right function .

[Partha]

I use the following code

function FRQ_Plot(NS,DNS)

global Fs fn wname tt lcf hcf

% plotting of the spectrogram

window = 1024; %window = Hamming window of length nfft. noverlap = (3/4)*window; %noverlap = Number of samples that each segment overlaps. nfft = []; %nfft = FFT length and is the maximum of 256 or the next power of 2 greater than the length of each segment of x. F = [0 10e6 20e6 30e6]; %F = Vector of frequencies (Instead of nfft).

[S_NS F_NS T_NS P_NS] = spectrogram(NS,window,noverlap,nfft,Fs,'yaxis');AMP_NS = abs(S_NS); [S_DNS F_DNS T_DNS P_DNS] = spectrogram(DNS,window,noverlap,nfft,Fs,'yaxis');AMP_DNS = abs(S_DNS);

figure(fn) subplot(211),imagesc(T_NS*1e3,F_NS*1e-6,AMP_NS),colormap(gray);colormap(flipud(colormap)),colorbar('location','northoutside'),set(gca,'YDir','normal') subplot(212),imagesc(T_DNS*1e3,F_DNS*1e-6,AMP_DNS),colormap(gray);colormap(flipud(colormap)),colorbar('location','northoutside'),set(gca,'YDir','normal') fn = fn + 1;

figure(fn) subplot(211),spectrogram(NS,window,noverlap,nfft,Fs,'yaxis'),colormap(gray);colormap(flipud(colormap)),colorbar('location','northoutside') subplot(212),spectrogram(DNS,window,noverlap,nfft,Fs,'yaxis'),colormap(gray);colormap(flipud(colormap)),colorbar('location','northoutside') fn = fn + 1;

return

Please find the attachments for figures

Which one is correct?