Hi grandong
I understand that you would like to reconstruct your signal from wavelet coefficients. You can use "wavedec" and "waverec" functions to decompose and reconstruct your signal instead of using "dyadup" and "dyaddown" functions.
Here is a sample code snippet to decompose a signal, calculate coefficients and reconstruct the signal:
% Original signal
x = [5 7 8 9]
% Wavelet decomposition using 'db2'
waveletName = 'db2';
level = 2;
% Decompose the signal
[c, l] = wavedec(x, level, waveletName);
% Extract coefficients
cA1 = appcoef(c, l, waveletName, level-1)
cD1 = detcoef(c, l, level-1)
% Reconstruct the signal
xReconstructed = waverec(c, l, waveletName)
You can refer to the following documentation links for more details on:
- wavedec: https://www.mathworks.com/help/wavelet/ref/wavedec.html
- wacerec: https://www.mathworks.com/help/wavelet/ref/waverec.html
- appcoef: https://www.mathworks.com/help/wavelet/ref/appcoef.html
- detcoef: https://www.mathworks.com/help/wavelet/ref/detcoef.html
I hope this answers your query.
