I need a matlab code for doing(1d) wavelet decomposition(DWT) in single observation with time

for example: if i done DWT with observation values with time what type results i can get..?? can any one guide me... please....

Answer 1

[Rodney Tan]

After 1D wavelet decomposition you will obtain a approximate low frequency and a detail high frequency components of your observation signal in time.

Example code from Matlab Help load noisdopp; [A,D] = dwt(noisdopp,'sym4');

A is your (Approximate) low frequency signal D is your (Detail) high frequency signal sym4 is the mother wavelet (namely symlet 4) used to decompose the signal. It determine how well it decompose the signal. So you need to know the observation signal and application well for you to choose the right mother wavelet. You will notice the resultant decompose time samples are half of the original time sample.

[J G RAO]

OK thank you for response sir. still, i have confusion with DWT method. can you solve the with my data (monthly rainfall data with 55 years time period) first time using this method in MATLAB software(actually i am civil engg student) i need to calculate: 1) what type of answers i got after calculation (if i solve) 2) plot for each level 1, level 2, level 3, and etc..... 3) plot explanation

please tell me sir thank you sir

i am waiting for your response.........

[afiq mohamad]

why the time sample become half ?

[J G RAO]

that is only example data sir..