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Owning Palette: Discrete Wavelet VIs
Requires: Advanced Signal Processing Toolkit
Designs customized analysis filters and synthesis filters for discrete wavelet analysis and reconstruction, respectively.
|Dialog Box Options|
|Block Diagram Inputs|
|Block Diagram Outputs|
|Wavelet Type||Specifies the type of wavelet this Express VI uses to design a customized wavelet for discrete wavelet analysis and reconstruction. You can select the Orthogonal or Biorthogonal option.|
|Product of Lowpass (P0=G0*H0)||Specifies P0, which is the product of the lowpass analysis filter G0 and the lowpass synthesis filter H0. Contains the following options:|
|Factorization (Type of G0)||Contains the following options:|
|Zeros of G0 and H0||Shows the distribution of the zeros of P0(z), G0(z) and H0(z). This Express VI uses this distribution to factor the zeros of P0(z) into the zeros of G0(z) and H0(z). Because the filter coefficients of P0(z) are real, all the zeros of P0(z) are symmetrical with respect to the x-axis. Consequently, this Express VI displays only the upper half of the plane. The zeros on the x-axis represent real-valued roots. The zeros outside of the x-axis represent complex-valued roots.|
The blue crosses represent the zeros of G0(z), and the red circles represent the zeros of H0(z).
Click on the zero you want to select to switch the zero from that of G0(z) to that of H0(z) and vice versa. All the zeros belong to G0(z) or H0(z).
Selecting different values for Filter type puts different constraints on the selections of zeros. For example, if you select Linear Phase for Filter type and select a zero for one filter, the filter automatically contains the reciprocal of the zero.
|Wavelet and Filter Banks||Displays the following graphs:|
|Frequency response||Displays the magnitude of the frequency responses of the designed filters G0(z) and G1(z). G1(z) is the sign-alternated version of H0(z). In other words, G1(z) is a highpass filter if H0(z) is a lowpass filter. This VI shows the frequency response of G0(z) in blue and shows the frequency response of G1(z) in green. The units of the y-axis are in dB, and the units of the x-axis are in terms of the normalized frequency. The full scale ranges from 0.0 to 1.0 pi.|
|error in (no error)||Describes error conditions that occur before this node runs.|
|Analysis filters||Returns the coefficients of the analysis filters.|
|Analysis scaling||Returns the scaling function of the analysis filter bank.|
|Analysis wavelet||Returns the mother wavelet of the analysis filter bank.|
|error out||Contains error information. This output provides standard error out functionality.|
|Synthesis filters||Returns the coefficients of the synthesis filters.|
|Synthesis scaling||Returns the scaling function of the synthesis filter bank.|
|Synthesis wavelet||Returns the mother wavelet of the synthesis filter bank.|