Poles/Zeros

>> Choose from file

This option (identical to Open File with GSE Calibration) allows you to load, display and further process calibration information ( poles, zeros, and scale factors  for seismometer systems) provided  in PAZ-GSE format. Here you will find 'calibration files' for particular problems from  'Of Poles and Zeros' (e. g. pr10_1.cal corresponds to Problem 10.1, etc.)  but also calibration files for standard instruments (e. g. woodande.cal corresponds to a Wood-Anderson seismometer). Depending on your mode of operation (WWW or CD), the files will either be loaded from the Web server or the CD. For a description of the GSE format see 'Of Poles and Zeros'.

Once a calibration file is loaded, the pole and zero positions  can be manually modified using  Modify and Enter or they can be displayed in map-view using the  Map option from the menu Poles/Zeros. It can further be used to display the corresponding frequency reponse function (see Show Response) or to filter another trace (see Filter with Response from Poles/Zeros in the Utilities menu).

>> Modify and Enter

A panel is displayed which prompts the user to enter complex positions (real and imaginary parts) for  poles and zeros as well as an amplitude scale factor (GSE format scale factor). Using the option Choose from file the corresponding values can also be read from file and subsequently be modified manually. To make the modified values valid for further processing press the Ok button or the Apply button (see General Hints for the difference between Ok and Apply). The Reset button removes all pole and zero positions and resets the scale factor to 1.

>> Map

Pole and zero positions (either entered manually or loaded from file using the Choose from file option) can be displayed in s-plane map view using this option.  Poles are shown as red crosses and zeros as blue circles. To modify poles or zeros move the mouse into a pole or zero and drag it to a new position. Conjugate complex pairs of poles and zeros are always handled together. To move poles or  zeros along circles in the s-plane press the SHIFT key before dragging  a pole or zero position using  the mouse.
 The make the modified values valid press the Ok button or Apply button.

>> Load Response for Fit

Problem 3.8 in 'Of Poles and Zeros' reqires to find poles and zeros of a seismometer system for which only the magnification curve has been given. In order to interactively compare this reference response with the one corresponding  to the user's  pole/zero distribution, the response  to be matched can be displayed as background plot in connection with the  Show Response menu options.

>> Delete Response for fit

Delete an existing reference response function and reset the background for the  Show Response menu to a clean window.