Window functions

Block diagram

Program parameters

The table below shows a list of important parameters for the configuration of the magnitude spectrum function blocks.

Calculation/specification of the overlap

Version 1: Use of the function F_CM_CalculateRecommendedOverlap

By means of the named function the recommended overlap can be calculated at runtime. After download/login, the necessary values are called in the MAIN_CM in the first cycle.

    IF bCalculateOverlap THEN
    // recommended overlap for window 1
    nOverlap1 := F_CM_CalculateRecommendedOverlap(eWindowType := cWindowType1, aWindowParameters := cWindowParameters1, nWindowLength := cWindowLength);

    // recommended overlap for window  2
    nOverlap2 := F_CM_CalculateRecommendedOverlap(eWindowType := cWindowType2, aWindowParameters := cWindowParameters2, nWindowLength := cWindowLength);

    // recommended overlap for window  3
    nOverlap3 := F_CM_CalculateRecommendedOverlap(eWindowType := cWindowType3, aWindowParameters := cWindowParameters3, nWindowLength := cWindowLength);

    bCalculateOverlap := FALSE;
END_IF
  

The lengths obtained in this way can subsequently be entered in the configuration of the analysis chains (parameters cOverlap1, cOverlap2, cOverlap3 in the GVL_Constants.). The dependencies in the buffer length must be observed here! After downloading/logging in again, the application is configured with regard to the overlap.

Version 2: Reading the initial parameters in the Online view

If the value nOverlap := cCM_OverlapRecommended is used with the initialization structure for the overlap, then the optimum overlap is calculated in the initialization phase of the function block, depending on the window parameters. This value can be read in the Online View of the function block in the node stInitPars after the download and login. With this variant it is not necessary to start the application!

Online View for Spectrum 2 (Hann window)

Requirements