TB 9-6625-2134-24
b. Adjustments. No adjustments can be made.
11. IF Gain and Display Accuracy
a. Performance Check
(1) Connect signal generator RF OUTPUT to variable attenuator and connect
variable attenuator to TI RF INPUT.
(2) Adjust signal generator frequency for 100 MHz at -20 dBm and set variable
attenuator switches to 0 dB.
(3) Position controls as listed in (a) through (h) below:
(a) FREQUENCY SPAN/DIV control to 20 MHz.
(b) AUTO RESOLUTION pushbutton on.
(c) VERTICAL DISPLAY 10 dB/DIV pushbutton on.
(d) VIDEO FILTER WIDE pushbutton on.
(e) REFERENCE LEVEL control to -10 dBm.
(f) MIN RF ATTEN control to 0 dB.
(g) FREQUENCY RANGE to 0-1.8 GHz.
(h) FREQUENCY control to 100 MHz (front panel indication).
(4) Adjust FREQUENCY SPAN/DIV control to 10 kHz.
(5) Position RESOLUTION BANDWIDTH control to 10 kHz and readjust trace to
center of crt using FREQUENCY control.
(6) Press VERTICAL DISPLAY 2 dB/DIV pushbutton on and adjust signal
generator for a 6 division display on crt, with the top of signal positioned on 7th graticule
(reference) line.
(7) Press MIN NOISE pushbutton on and observe crt display for signal level shift.
Shift will not exceed 2 minor divisions.
(8) Adjust signal generator output to reposition signal level to graticule reference line.
(9) Increase REFERENCE LEVEL control by 1 dB and add 1 dB with variable
attenuator. Record difference from reference line.
(10) Repeat technique of (9) above until REFERENCE LEVEL is -20 dB. Total
cumulative error must not exceed 1.5 minor divisions. (Add additional .5 dB when stepping
from -19 to -20).
NOTE
Gain steps are monotonic (same direction) with the following
limits: Within 0.2 dB/dB to a maximum of 0.5 dB/9 dB except
at the decade transitions of -19 to -20 dBm, -29 to -30 dBm, -39
to -40 dBm, -49 to -50 dBm, -59 to -60 dBm, and -69 to -70 dBm,
where an additional 0.5 dB can occur for a total of 1.0 dB per
decade. Maximum deviation of the 90 dB range is within
2 dB.
