Expansion windowing system for a measurement test instrument

摘要

A system for expanding a waveform in a measurement test instrument has a display area containing a waveform representative of data acquired by a measurement test instrument and an active movable cursor intersecting the waveform. The system has first and second viewports with the first viewport displaying the waveform in the display area and the second viewport displaying a portion of the waveform from the first view port in an expanded form when the second viewport is in the display area. The second viewport has a center point and dimensions defined in the first viewport with the center point being defined by the intersection of the active movable cursor with the waveform and the dimensions being defined with respect with the center point. The second viewport is movable within the first viewport as a function of movement of the cursor. Means are provided for varying the dimensions of the second viewport about the cursor/waveform intersection when the first viewport is in the display area and for further expanding the waveform in a continuous manner about the cursor/waveform intersection when the second viewport is in the display area. Means are provided for replacing the first viewport with the second viewport in the display area.