This component performs an on-line Discrete Wavelet Transform (DWT) on the input signal. The outputs A and D are the reconstruction wavelet coefficients:
A: The approximation output, which is the low frequency content of the input signal component.
D: The multidimensional output, which gives the details, or the high frequency components, of the input signal at various levels (up to level 6)
Before the actual DWT is performed, the input signal is sampled at a rate, which is a user-specified input parameter. An option is also provided to enable or disable the internal anti-aliasing filter, and the type of mother wavelet along with its order may be selected from a list. This component supports several most commonly used types of mother wavelets:
Harr
Daubechies (order 1, 2, 4, and 8)
Symlets (order 1, 2, 4, and 8)
Coeiflets (order 1 and 2)
The user can specify the level of detail computed. This selection will change the dimension of the output D to be equal to the number of levels selected. The output A will then correspond to the approximation at the selected level. For example, if the selected level is 1, the output signal A will be the approximation coefficient A1, and the output D is the detail coefficient D1. If level 2 is selected, the output A will give the approximation coefficient, A2, and the output D, which is now two dimensional, gives detail coefficients D1 and D2. Currently, this component allows calculation of details up to level-6, where higher levels represent the lower frequencies.
The amount of simulation time steps required to perform the wavelet transformation depends on the selected sampling frequency, mother wavelet type and the number of detail levels required. Therefore, output signals will exhibit a time delay with respect to the input signal; the amount of delay will depend on the selected parameters.
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