How to inspect time-frequency results

If you are unsure of how to look at time-frequency results, this video has the 5-step plan that you need! It also discusses whether time-frequency features can be interpreted as "oscillations."

[zinwaroo]

I understand about the signal annotation by watching your lecture. Thank you so much. Now I am trying research for EEG signal feature annotation with machine learning approach.

[DL-vdmr]

Hi, me again...the one who asked about R. Then I go to matlab...to compare... I used cwt to transform a monthly precipitation data. I have 1320 month. So I set my fs as 1 (month) dt as 1, time start as 0 time end as 1320. Then I use [wt, f, coi] =cwt(precipitation, ‘amor’, fs). Then my y-axis is frequency. The unit shows mhz. I am confuse here...how the wavelet window’s frequency connects to the time of the time series? See vertically I see frequency range from 0 to 100+, so for example what does 10 represent? So can I say this signal occurs each 10 month when there is high magnitude around frequency 10? Hope I made myself clear.

[DL-vdmr]

For my monthly data, Is frequency 10 in Y axis mean 10 month? Can I explain it as every 10 month there is wavelength repeated it self if I see a high magnitude.

[franziskal]

Hi :) Thank you for that awesome video. I have some trouble to understand the values of the color bar. How do they reflect power? When you do the coding to create such a plot, you set a minimum and maximum value for this color bar. What changes when you change those range? If you set it for example to -0.5 to 0.5 and a value at a given frequency and time is 0.6, is that value not displayed anymore?

[sophies]

Hi Mike, thanks so much for this! When I’m looking at components, instead of channels, at how many components should I look like? I’m unsure between the difference of component and channel (channel is the number of electrode isn’t?)

[DL-vdmr]

Ha I found it I should use [wt, periods, coi] = cwt(data, ‘amor’, years(1/12))...then Y axis related to time too. Happy about it. Another question do you know how to get significant line. I saw some paper they made significant contours or curves for the magnitude. But don’t know how...

[khalfanalkharusi]

Thank you Mike. I would recommend to include the signal in time domain with time-frequency spectrum in order to have better understanding of the physical property of the system under study.

[onusbaum]

How about extracting meaningful Information from those nice color maps, using Principal Component Analysis (PCA) for instance ?

[haneensuradi]

Hi Mike,
Thank you for the very informative lectures. I have a very general question. After conducting an experiment under two conditions, collecting data and pre-preprocessing it (including ICA rejection). From where to start the analysis? ERP or TF analysis? Which electrodes and which frequency bands? I am not looking for a specific answer but more for a methodology. Sorry if my question is too basic.

[stefanyleonpalacios]

What program are you using? Can you do a tutorial ??

[rblack]

Hey Mike. I've commented on one of your other videos before. Learned a lot from them, thanks! It would be cool if you would check out my YouTube channel; I have some videos on additive synthesis and signal recognition. It would be cool if you could take a look! Also, what program do you use for screen capture?-Ryan

[jayagupta]

hii mike, your video is quite helpful. i wanted to send my query to you personally. can you please provide my your email id