Tektronix 1705A - page 121

Checks and Adjustments
5-26 1705A Spectrum Monitor
e. Turnthe CENTER FREQUENCY control counterclockwise until the
frequencyreadout display is 1800 MHz.
f. ADJUST --R38 (Offset) to position the 1800 MHz markerdirectly
under the caret.
g. Set the signal generatorFrequency to 1000 MHz.
h. Turnthe CENTER F REQUENCY control to display1000 MHz.
i. ADJUST --R37 (Offset Gain) to position the 1000 MHz marker directly
under the caret.
j. Repeat this step until themarkers at 1800 and 1000 MHz are properly
positioned.
16. Adjust Intensified Zone Range
a. Set the SPAN/DIVto FULL.
b. Set the signal generatorFrequency to 1400 MHz, and Amplitude to --30
dBm.
c. Adjust the CENTER FREQUENCY control so the readout displays 1400
MHz.
d. ADJUST--R61 to center the intensified zone on the 1400 MHz marker.
e. Set the leveledsine wave generator Frequency to 1000 MHz.
f. Turnthe CENTER FREQUENCY control counterclockwise to 1000
MHz.
g. ADJUST--R36 to center the intensified zone on the 900 MHz marker.
h. Repeat this step until theintensified zone is centered on appropriate
markers.
17. Adjust Vertical Gain
a. Set the 1705A SWEEP SPEED fully counterclockwise.
b. Set the signal generatorFrequency to 1400 MHz, and Amplitude to
--30 dBm.
c. ADJUST-- R176 for a three-Divisionshift (±0.25 major Divisions)
when switching the input levelbetween --30 and --60dBm.
d. Set VERTICALP OSITION to placethe noise floor one major Division
up from the bottom graticule line.