S Transform

• Implement a new algorithm of S transform which involves lesser computational complexity.

• Estimate power quality indices and time-frequency analysis of power signals using that algorithm.

What I need to do

• Discovered in 1994 by Stockwell and his coworkers for geophysical data analysis as time frequency decomposition tool.

• Utilizes frequency dependent variable window so that window width should be adjusted according to frequency present in power signal.

• Thus gives frequency dependent resolution and hence better signal clarity in time-frequency domain

• Only few algorithm of S Transform have been given till now and even these needs improvement

Brief introduction to S transform

• Provides better, frequency dependent(STFT) resolution in time-frequency(DWT) domain with least noise(Wigner-Ville/DWT)

• Gives information about relative amplitude of various sinusoids present in signal at any time

• Information about absolute phase of sinusoids at any time

• Frequency marginal gives FT of signal and hence signal can be recovered easily by inverse FT

Why S transform

STFTC:\Users\shantanu\Documents\MATLAB\project\stft programs\

stft_varring_window.m

DWTC:\Users\shantanu\Documents\MATLAB\project\wavelet\most_significant_wavelet_untill_now1.m

WignerC:\Users\shantanu\Documents\MATLAB\shan\project\wigner ville

distribution function not transform\wigner distribution.m

StockwellC:\Users\shantanu\Documents\MATLAB\project\S transform\my_stran.m

Comparison with others in general terms (simulation)

• As it involves multiplication of three terms thus large no. of additions and multiplications have to be calculated.

Problems in S Transform

• Selective frequency scaling

• Window cropping

Idea To Resolve Computational Complexity

Simulation results

THANK YOU