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jon erickson

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14 Oct 2014 Screenshot continuous wavelet transform and inverse Continuous wavelet transform (CWT) and Inverse CWT for reconstructing original signal. Author: jon erickson cwt, inverse, time frequency, wavelets, wavelet, signal processing 113 19
  • 4.6
4.6 | 5 ratings
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03 Sep 2014 Gaussian smoothing filter Function to smooth a time series using a Gaussian filter. Author: James Conder

Works fine, but implementation is could be improved/sped up by using conv(...) instead of a for loop to compute filtered waveform

10 Jan 2014 PLOT_GAUSSIAN_ELLIPSOID Plots two- and three-dimensional Gaussian distributions Author: Gautam Vallabha

works great and excellent documentation. thanks!

19 May 2013 continuous wavelet transform and inverse Continuous wavelet transform (CWT) and Inverse CWT for reconstructing original signal. Author: jon erickson

Venkata:
If you want to isolate a single scale (frequency) in the reconstruction, then zero out all coefficients for all scales and all time, except the selected scale. Then reconstruct.

Trevor: Yes, you are correct. Filling in zeros for gaps ensures those terms (time points) ensure the sums remain unchanged.
Just add 'haar' in the list of available wave bases, as you suggest.

12 Oct 2011 continuous wavelet transform and inverse Continuous wavelet transform (CWT) and Inverse CWT for reconstructing original signal. Author: jon erickson

Alexandre: MATLAB did not used to have the inverse cwt function in their wavelet toolbox as of 2008. Hence, at that time, it was filling a gap--that matlab hadn't yet implemented. I have not used the newer version of matlab wavelet toolbox, but my guess is that it is the same concept, but less full-fledged.

Zahra: CWT does not share the same notion of details and approximations--that is DWT only.

02 Apr 2011 continuous wavelet transform and inverse Continuous wavelet transform (CWT) and Inverse CWT for reconstructing original signal. Author: jon erickson

If by "instantaneous frequency" you mean the "equivalent Fourier frequency" (i.e. sine wave in infinite time domain at oscillating at a single frequency), then here's the answer. The CWT "pseudofrequency" depends on the mother wavelet you use for the transform. Each mother wavelet has a corresponding "center frequency", and the relation is given as:

f = centerfrq(mother)/(a*delta).
a = scale
delta = sampling period.

I strongly encourage you to read up on wavelet theory, in order to become a competent user of this code.

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15 Oct 2014 continuous wavelet transform and inverse Continuous wavelet transform (CWT) and Inverse CWT for reconstructing original signal. Author: jon erickson Greg

Clean, concise, simple to use, excellent results. Thank you very much! If a few more wavelets could be added in the future, would be much appreciated.

19 May 2013 continuous wavelet transform and inverse Continuous wavelet transform (CWT) and Inverse CWT for reconstructing original signal. Author: jon erickson jon erickson

Venkata:
If you want to isolate a single scale (frequency) in the reconstruction, then zero out all coefficients for all scales and all time, except the selected scale. Then reconstruct.

Trevor: Yes, you are correct. Filling in zeros for gaps ensures those terms (time points) ensure the sums remain unchanged.
Just add 'haar' in the list of available wave bases, as you suggest.

24 Jan 2013 continuous wavelet transform and inverse Continuous wavelet transform (CWT) and Inverse CWT for reconstructing original signal. Author: jon erickson trevor

Hi Jon,

Thanks for this fantastic code!
A question regarding time series with gaps:
As I understand, the Haar wavelet will ignore gaps, as long as they are replaced by zeros and the time series is zero-meaned. If this is correct, could you include (either here or in the wave_bases.m file) code for the Haar wavelet?

Thanks again.

22 Nov 2012 continuous wavelet transform and inverse Continuous wavelet transform (CWT) and Inverse CWT for reconstructing original signal. Author: jon erickson Venkata

The example you have provided works fine. But, when I apply to my data, the reconstructed signal seems to be scaled down.

Secondly, could you plz tell me how to reconstruct only a particular periodic signal (frequency) from the wavelet coefficients..?

Thank you.

13 Nov 2011 continuous wavelet transform and inverse Continuous wavelet transform (CWT) and Inverse CWT for reconstructing original signal. Author: jon erickson ernesto

hey friends Im working with myoelectric signal and i need to use the wavelet transform for processing the signal and i need some like a tutorial for get some knowledge

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