HP (Hewlett-Packard) 8591C User Manual

 X FINE TUNE DAC, 6-5, 

 

 Spc Clear, 

 ZERO MARKER, 

ZERO SPAN, 

 

ZONE CENTER,   155
ZONE PK LEFT, 
ZONE PK RIGHT,   156
ZONE SPAN,   156
ZOOM,   156

zooming a window,