pez_edit
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Edit Poles and Zeros
graphics/pez_edbu.gif
By pressing the Edit By Co-Ord button from the main menu, the user may numerically edit any Pole or Zero in the complex Z-Plane. The following menu will appear for the user to make changes to the filter:

 

graphics/pez_edit.gif
 
 

The basic procedure for editing a pole/zero's co-ordinates is to

  1. Press the Select a Pole or Zero Button
  2. With the cross-haired cursor, select a pole/zero to edit. If a pole/zero was selected, values will appear in the real/imag/mag/angle edit boxes, and the Make Current Change button will appear. (Aligning the cross-hairs may not always be easy)
  3. Edit the Co-Ordinates numerically, pressing enter after each change. PeZ only reads an edit box when it receives an enter.
  4. Press the Make Current Change button to finalize the change.
Next to the Angle edit box is a selection list that allows the user to change between different angle units and normalizations. Selecting it will adjust the necessary co-ordinates.

When done, press the Done Editing button to return to the main menu.


 

Edit by Mouse Drag
graphics/pez_rt.gif

 PeZ allows users to move poles and zeros graphically with the mouse. Simply hold the left mouse button down while the mouse is above a pole or zero, and move it around the Z-Plane without letting go of the left mouse button. To make selection easier, the user may also click on a pole's or zero's multiplicity in the same manner and PeZ will understand that the particular pole/zero is to be moved.
 

Real-Time Mouse Drag

Clicking on the Real Time Drag Plots checkbox tells PeZ that the user wants to see how the plots looks as the user drags poles or zeros around in the Z-Plane. While a great deal of work has been done to optimize calculations for real-time plotting, some machines may not be able to keep up with the user's pole/zero dragging. Should the PeZ fail to keep up with the user, turn off the Real-Time Drag Plots option to move poles and zeros smoothly.

While a user is moving a pole/zero around with the rt-drag option turned on, the figure plots' axis are held constant to the scale of their starting values. This helps give users a better idea of how the positioning affects the plots, relative to a constant scaling. When a position is finalized by releasing the mouse button, PeZ rescales the axis to better show the new data points.

Implementation note: Due to inconsistencies in the Macintosh's version of Matlab, the real-time display will not be as smooth as on other computers. This appears to be a bug for Matlab v5.1, but in any case the real-time plotting should be acceptable.
 
 

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