Tektronix 1705A, Instruction Manual

Page: 119 / 223

Checks and Adjustments
5- 24
1705A Spectrum Monitor
g. Set the signal generator Frequency to 5.0 MHz, and the Amplitude to
+10 dBm.
h.
Position the first marker at the extreme left graticule.
i. ADJUST -- R49, R56, R48, then adjust R57 to position one marker per
major Division over the 10 major graticule Divisions,
±
1 minor
Division. (All these adjustments affect dc level of ramp start in 70 MHz
tuner.)
11. Adjust 10 kHz Filter
a. Remove the comb generator and reconnect the cable from the signal
generator to the 1705A 70 MHz INPUT.
b. Set the signal generator Frequency to 70 MHz, and the Amplitude to --25
dBm.
c. On the 1705A set SPAN/DIV to 100 kHz, adjust CENTER FREQUEN-
CY to position the marker onto the screen, and set RESOLUTION to 10
kHz.
d. ADJUST -- C52, C62, and C64 for a tall, symmetrical signal (
¶
6
Divisions).
e.
Set RESOLUTION to 300 kHz, and turn SWEEP SPEED fully
counterclockwise.
f. ADJUST -- R175 to match the signal amplitude of the highest point of
the 300 kHz filtered marker with the tip of the 10 kHz filtered marker
while switching between 10 kHz and 300 kHz RESOLUTION.
12. Adjust L--Band Linearity
a. Set INPUT to L--BAND and SPAN/DIV to 10 MHz. Adjust the
HORIZONTAL POSITION control to center the caret, and then set
SPAN/DIV to FULL.
b. Connect the signal generator output to the L--BAND INPUT.
c. Set the signal generator Frequency to 900 MHz, and Amplitude to --30
dBm.
d. ADJUST -- R35 to position the signal on the extreme left graticule.
e. Connect the signal generator output to the L--BAND INPUT through the
comb generator.
f. Set the signal generator Frequency to 100 MHz, and Amplitude to +10
dBm.