geophysical data are always affected by different sources of anomaly. these sources are classified in to three groups: first group is relatively deep sources commonly called as regional effects, second group is near surface sources or local effects and third group is high frequency noises. the only common way to separate the anomaly is separation with respect to the signal frequency. there are ...

The Fast Fourier Transform (FFT) reduces the number of computations required for the straightforward calculation of the discrete Fourier transform. For a one-dimensional signal of length N , this provides a reduction in complexity from O(N) to O(N log2 N) operations. Recently, fast algorithms have been introduced for discrete Fourier transforms on nonequispaced data sets (NDFT). These algorithm...

The Fourier transform (FT) nicely represents a wiggling, sinelike data set with only a few peaks in the frequency domain. But while the FT is appropriate for simple stationary data like harmonic waves, complicated signals or images require more elaborate transforms. These transforms must catch fast local variations, detect blurred object contours, differentiate textures, and capture different s...

We propose an algorithm that uses the discrete wavelet transform (DWT) as a tool to compute the discrete Fourier transform (DFT). The Cooley-Tukey FFT is shown to be a special case of the proposed algorithm when the wavelets in use are trivial. If no intermediate coeecients are dropped and no approximations are made, the proposed algorithm computes the exact result, and its computational comple...

In this paper, we propose a fast multi-resolution transform using wavelet packet transform (WPT). This fast algorithm switches between a transform coder and a subband coder on user discretion. The proposed algorithm uses discrete approximate trigonometric expansions, which have previously been proposed for exploiting spatial and spectral correlation in multidimensional signals. Specifically, we...

We propose an algorithm that uses the discrete wavelet transform (DWT) as a tool to compute the discrete Fourier transform (DFT). The Cooley-Tukey FFT is shown to be a special case of the proposed algorithm when the wavelets in use are trivial. If no intermediate coe cients are dropped and no approximations are made, the proposed algorithm computes the exact result, and its computational comple...

Microring resonators (MRRs) can be used to generate optical millimetre-wave solitons with a broadband frequency of 40–60 GHz. Non-linear light behaviours within MRRs, such as chaotic signals, can be used to generate logic codes (digital codes). The soliton signals can be multiplexed and modulated with the logic codes using an orthogonal frequency division multiplexing (OFDM) technique to transm...