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jon erickson

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25 Feb 2011 Screenshot continuous wavelet transform and inverse Continuous wavelet transform (CWT) and Inverse CWT for reconstructing original signal. Author: jon erickson time frequency, wavelets, cwt, wavelet, inverse, signal processing 57 18
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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.

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

Please note that the reconstructed signal is always centered. That is, the reconstruction process does not/cannot account for any 'dc offset' in the original signal.

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

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

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

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.

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