Checks and Adjustments
5-20 1705A Spectrum Monitor
3. Adjust Geometry,Focus, and Astigmatism
Display the DAC test patternby completing parts a. through c.
a. Press both the 1705A SPAN/DIVbuttons simultaneously to display the
Main Menu.
b. Press eitherS PAN/DIVbutton to move the cursor to TEST, then press
the INPUT button to display the TEST menu.
c. Press eitherS PAN/DIVbutton to move the cursor to DAC, then press
the INPUT button to display the DAC test pattern.
d. Set the front-panelFOCUS control so that it is approximatelyat the
centerof its rotation.
e. ADJUST --R45 (GEOM) for 35V 1V at pin 1 of J3.
f. ADJUST -- R11(CTR FOCUS) and R49 (ASTIG) for the most
clearly-defined DAC test pattern. SeeFigure 5-8.
Tek
REF
--10
--20
--30
--40
--50
--60
--70
L
O
G
+f
Figure5 -8: DAC check waveforms used to check Focus, Astigmatism, Geometry,
andset ting of the TraceRot ation( DAC test pattern may vary in size from instru-
ment to instrument)
4. Adjust TraceRotation
a. ADJUST --the front-panel TRACE ROTATIONpotentiometer for a
level display,using a crt graticule line as a reference.