Time-frequency methods provide more viable solutions than Fourier methods for signals that are shorter in time and not necessarily periodic. Methods such as Wavelet and Gabor transforms are considered to be T-F techniques.
Questions tagged [time-frequency]
87 questions
0
votes
0 answers
comparing two time series analysis
I currently have a dataset. I wanted to get your opinion on this. The data is as follows: there is a production line. A longitudinal plate as wide as the hand is produced. I am sending the photo. 10 cm wide. 5mm thick. Deformations are seen at some…
celikkanat
- 11
- 4
0
votes
0 answers
How can I get weekly data with this code?
Do you know with this code how can I get weekly datas ? because the output is only daily and I did not find the answer ...
start = datetime(2018,1,1)
end = datetime(2022,1,16)
stocks = ['DUK']
def ImportDataClose(name,start,end):
n =…
SC4RTOM
- 11
0
votes
1 answer
Does not the Bode Diagrama of the inputs of the system?
I am implementing a python code that performs with a Bode Diagram of a dynamic system. Nevertheless, according to a command available at the library of "Signal.Processing" of Scipy, the Bode diagram does not depends of the inputs of the dynamic…
Igor Gonzaga
- 31
- 1
0
votes
0 answers
why does Non negative matrix Factorization decompose a spectrogram into time and frequency component?
When i compute NMF over a spectrogram (mag of stft of a signal ) i obtain
W,H = NMF(MyStft,r) # where r=2 is the rank
W and H will respectively contain the spectrum and the temporal information.
My question is why? whats the logic behind…
Rebecca20
- 13
- 3
0
votes
0 answers
DateIF and countif? Excel formula
I have a list of IDs that have multiple dates and I am trying to count the months for each specific eeid to calculate a timeframe how long someone is on medication.
So far, I did a countif(A:A,A) showing how many times the eeid shows up but now I am…
Jmar
- 13
- 4
0
votes
1 answer
what is the ideal parameters for spectrogram of eeg signal?
I am trying to plot a spectrogram of an EEG signal whose sampling rate of 1000Hz and is filtered with a bandpass of 14 - 70 Hz, and the length of the signal is 440 ( and I cant increase the length of the signal). The signal(data link here) looks…
Alankrit
- 658
- 1
- 6
- 17
0
votes
0 answers
Chirp signal won't generate continuous frequency band
I am trying to apply an AC signal with a continuous "band" of frequencies, I generate the waveform in MATLAB and use the welch spectrum analysis to get a nice continuous band of frequencies from f1 to f2. When I actually generate the wave with a…
0
votes
1 answer
convert numpy array of float64 values to datetime64 with python and pandas
If I have a NumPy array of float64 values. I know these values represent dates in format of datetime64[ns]. I try to convert them with pandas. But I get an ValueError: Inferred frequency 86400N from passed values does not conform to passed frequency…
till Kadabra
- 478
- 9
- 21
0
votes
1 answer
Frequency count method
I'm a newbie in data structures, this question appeared in a model question paper.
Calculate the frequency count of the statement x = x+1; in the following code segment
for (i = 0; i< n; i++)
for (j = 0; j< n; j*=2)
x = x + 1;
My…
Agatha Wilson
- 1
- 1
0
votes
0 answers
Effect of Change of Audio Bitrate on Spectrograms
I was working on changing bitrates of some MP3 files from 160kbps to 80kbps just to see how it affects the audio quality and frequencies. So I plotted the spectrogram for both waves and it looks something like this (Upper one being 80Kbps…
Darshan Deshpande
- 81
- 2
- 6
0
votes
1 answer
How to denormalize values to do the Harmonic Product Spectrum
I'm trying to execute the HPS algorithm and the results are not right. (48000Hz, 16bits)
I've applied to a buffer with the recorded frequency several splits, then a Hanning window, and finally the FFT.
I've obtained a peak in each FFT, that…
Meliodas
- 1
- 2
0
votes
3 answers
What is the relationship between the number of time bins in stft and the actual time in the signal?
I have a 9 minutes files which the sampling rate of that is 16000. My signal has totally 9*60*16000= 8640000 samples. I am doing a stft in python (librosa package) and plotting spectrogram. I know the frequency resolution of spectrogram is equal to…
Zahra
- 43
- 8
0
votes
0 answers
How to plot multiple line graphs in one graph from a function that generates 3 graphs in a single command?
I am using frequencyConnectedness package in which one function plotOverall genrates 3 graphs one after another on pressing enter to continue. I need to plot all three graphs into one graph. How to do this ?
For sample data kindly use the dataset…
NSF
- 23
- 6
0
votes
0 answers
First day of the week problem while using xts's period.apply()
I am trying to convert my daily series to weekly frequency by using xts package. However, I couldn't figure out how to dictate the first week of my series is Sunday. Documentation on function doesn't refer any arguments which can be used for this…
omzeybek
- 305
- 2
- 14
0
votes
1 answer
How to obtain daily time series of categorical frequencies in R
I have a data frame as such:
data <- data.frame(daytime = c('2005-05-03 11:45:23', '2005-05-03 11:47:45',
'2005-05-03 12:00:32', '2005-05-03 12:25:01',
'2006-05-02 10:45:15', '2006-05-02…
user111417
- 143
- 1
- 9